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How often should hydraulic tests of boilers be carried out? Frequency of hydraulic tests of boilers. Hydraulic testing and boiler insulation

After the end of all repair work(before applying protective coatings and insulation) steam boilers are subjected to a hydraulic test and a steam test in the presence of the Surveyor to the Register.
Hydraulic tests carried out under the condition that the boiler is completely filled with water and air is removed, in the presence of two sealed pressure gauges and at a temperature of water and ambient air not lower than + 5 C. At the same time, the temperature difference between water and ambient air should exclude the possibility of sweating.
During the test, the pressure should not increase rapidly, it is forbidden to perform work on the ship that causes noise or knocking.
The hydraulic test is carried out in the following order: raising the pressure to the working pressure, preliminary inspection at the working pressure, raising the pressure to the test pressure with a holding time (with the pump turned off) for 10 minutes, lowering the pressure to the working pressure and inspection.
If during the hydraulic test knocks are heard in the boiler or other abnormal phenomena are noticed, the tests are interrupted and after the release of water, the boiler is carefully inspected to determine the location and nature of the damage. After the defect is eliminated, the test is repeated.
The boiler is recognized as serviceable if during the inspection no leaks, residual deformations, ruptures of seams and other signs of violation of the integrity of any parts and connections are found.
The steam sample of the boiler is carried out in combination with fittings, equipment, service mechanisms and pipelines, at operating pressure. At the same time, it is necessary to make sure that the water-indicating devices (water-gauge glasses, test taps, remote water level indicators, etc.) are in good condition, as well as the upper and lower blowing of the boiler. They check the condition of the fittings, the operation of the drives, the absence of steam, water, fuel leaks in glands, flanges and other connections.
Safety valves are tested in operation for operation. They must be adjusted to the following opening pressures: P open. less than 1.05Рр (at Рр less than 1.0 MPa); R open more than 1.03Рр (when Рр is more than 1.0 MPa), where Рр is the working pressure.
Maximum allowable pressure valve opening should not exceed 1.1 Rr. The safety valves of superheaters must be adjusted to operate with some advance of the boiler valves.
Check in action manual drives rupture of safety valves. If the results are positive, they will be sealed by the Register inspector.
Checking the operation of systems automatic regulation Military-industrial complex: reliability and timeliness of the operation of signaling, protective and blocking devices (when the water level in the boiler drops below the permissible level, the air supply to the furnace is interrupted, the torch in the furnace is extinguished and in other cases provided for by the automation system).
Check the operation of the military-industrial complex during the transition from automatic to manual control and vice versa.
After the end of the steam test and the elimination of the identified defects, they begin to insulate the boiler. The surfaces of the boiler to be insulated, as well as the frame and casing, are cleaned and painted with red lead or AL 177 paint.
The insulating material is soaked in hot water and applied to the hot insulated surfaces with a layer of 10-30 mm. After the first layer has dried, a second layer is applied, and so on, until insulation is obtained. desired thickness. The thickness of the insulation depends on the temperature of the working medium (for boilers - 60-100 mm).
As an insulating material for ship boilers, asbestos fluff, asbestos cloth, asbestos cardboard, asbestos cord, diatomite (diatomaceous earth), asbozurite (a mixture of asbestos with diatomite), sovelit and newvel - a mixture of magnesia MgO and magnesium oxide hydrate Mg (OH) 2 with asbestos.
To save expensive insulating materials (soverite, newel), insulation is made up of different materials. For example, the first layer - 10 mm - is applied from fluff asbestos, the second - 40-50 mm thick - from sovelite or nuvel, the third - 10 mm thick - from asbozurite.
Insulating materials applied to the surfaces of the boilers hold together metal mesh and covered with galvanized iron roofing. Overlay steel bandages. The boilers are also insulated with mattresses made of asbestos fabric filled with sovelite or nuvel. The mattresses are sewn together with brass wire, laid on the insulated parts of the boiler, fitted with bandages and covered with a metal casing.
The walls of the combustion chamber and gas ducts of water-tube boilers are sheathed with removable shields made of thin steel sheets insulated with asbestos cardboard (or other insulating material) with a thickness of at least 10 mm. Asbestos is attached to the shields with bolts, and the shields are attached to the boiler frame on the battens. All joints of the boiler casing are made on asbestos gaskets, which ensures the gas-tightness of the casing.

To check the strength of the structure, the quality of its manufacture, all elements of the boiler, and then the boiler assembly, are subjected to hydraulic tests with test pressure. R etc. Hydraulic tests are carried out at the end of all welding work, when insulation and protective coatings are still missing. The strength and density of welded and rolling joints of elements is checked by test pressure R pr = 1.5 R r, but not less Rр + 0.1 MPa ( R p is the working pressure in the boiler).

Dimensions of elements tested by test pressure R p + 0.1 MPa, as well as elements tested with a test pressure higher than indicated above, must be subjected to a verification calculation for this pressure. In this case, the stresses should not exceed 0.9 of the yield strength of the material σ t s , MPa.

After final assembly and installation of fittings, the boiler is subjected to a final hydraulic pressure test R pr = 1.25 R r, but not less Rр + 0.1 MPa.

During hydraulic testing, the boiler is filled with water and the working water pressure is adjusted to the test pressure. R pr special pump. The test results are determined by visual inspection of the boiler. As well as the rate of pressure drop.

The boiler is recognized as having passed the test if the pressure in it does not drop and no leaks, local bulges, visible changes in shape and residual deformations are detected during inspection. Sweating and the appearance of small water droplets at the rolling joints are not considered leaks. However, the appearance of dew and tears at the welds is not allowed.

Steam boilers, after being installed on board, must be subjected to a steam test at operating pressure, which consists in the fact that the boiler is put into service and checked in operation at operating pressure.

Gas cavities of utilization boilers are tested with air at a pressure of 10 kPa. Gas ducts of auxiliary and combined PCs are not tested.

4. External inspection of steam boilers.

External inspection of boilers complete with apparatus, equipment, service mechanisms and heat exchangers, systems and pipelines is carried out under steam at operating pressure and, if possible, combined with a test of the ship's mechanisms in operation.

During the inspection, it is necessary to make sure that all water-indicating devices (water-gauge glasses, test taps, remote water level indicators, etc.) are in good condition, as well as that the upper and lower blowing of the boiler is working properly.

The condition of the equipment, the serviceability of the drives, the absence of steam, water and fuel leaks in glands, flanges and other connections should be checked.

Safety valves must be tested in operation for operation. The valves must be adjusted to the following pressures:

valve opening pressure

R open ≤ 1.05 R slave for R slave ≤ 10 kgf/cm 2 ;

R open ≤ 1.03 R slave for R slave > 10 kgf/cm 2 ;

Maximum allowable pressure with safety valve R max ≤ 1.1 R slave.

The safety valves of superheaters must be adjusted to operate with some advance of the boiler valves.

The operation of the manual actuation of the safety valves shall be checked.

With positive results of external examination and verification in operation, one of the boiler safety valves must be sealed by the inspector.

If it is not possible to check the safety valves on the recovery boilers in the parking lot due to the need long work of the main engine or the impossibility of supplying steam from an auxiliary fuel-fired boiler, then checking the adjustment and sealing of the safety valves can be carried out by the shipowner during the voyage with the execution of the relevant act.

During the survey, the operation of the automatic control systems of the boiler plant should be checked.

At the same time, you should make sure that the alarm, protection and blocking devices work flawlessly and are triggered in a timely manner, in particular when the water level in the boiler drops below the permissible level, when the air supply to the furnace is interrupted, when the flame in the furnace is extinguished and in other cases provided for by the automation system.

You should also check the operation of the boiler installation when changing from automatic to manual control and vice versa.

If during the external examination defects are found, the cause of which cannot be established by this examination, the inspector may require an internal examination or hydraulic test.

How often should hydraulic tests of boilers be carried out? Frequency of hydraulic tests of boilers

Hydraulic testing of boilers and pipelines

In accordance with the rules of the Gospromatomnadzor of the USSR, boilers, superheaters and water economizers operating under overpressure more than 0.07 MPa, as well as hot water boilers with a water heating temperature above 115 ° C, they are registered with the USSR Gospromatomnadzor and subjected to a technical examination.

Technical certification consists of internal inspection and hydraulic testing of units. Superheaters and economizers, constituting one unit with the boiler, will be examined simultaneously with it.

The boiler is inspected inside, checking for cracks, ruptures, metal corrosion, violations of rolling and welded joints, and other possible defects.

A hydraulic test is performed to check the strength of the pressurized elements of the boiler and the tightness of their connections. Hydraulic test is subjected to drums and chambers of steam boilers, screen and convective pipe systems, superheaters and water economizers. Hydraulic tests individual elements and blocks carried out on an enlarged installation site are not exempt from hydraulic testing of the installed equipment.

Before the start of the hydraulic test, all hatches and manholes of the boiler are closed, on which permanent gaskets are installed, shut-off valves that disconnect the boiler unit from other devices and pipelines, and plugs are installed between the boilers and safety valves. For testing, the boiler is filled with water at a temperature not higher than 60 and not lower than 5 °C at an ambient air temperature not lower than 5 °C. When filling the boiler with water, air is removed through a safety valve or a special air cock.

To fill the boiler with water and create a test pressure, which is increased gradually and smoothly, an electric pump or a manual hydraulic press is used. The test pressure is maintained for 5 minutes, after which it is gradually reduced to the working one. In the event of a pressure drop, find out the place where the water passes. With a slight decrease in pressure due to leaky fittings, the hydraulic test can be continued, while the test pressure is maintained by pumping water, but not more than 5 minutes. The water pressure in the boiler is measured by two tested pressure gauges, one of which must be a control one.

The boiler unit is inspected at operating pressure, tapping the welds with light blows of a hammer weighing no more than 1.5 kg. Special attention pay attention to the density of welds, rolling and flanged joints. If, when testing the boiler, shocks, noise, knocking are heard inside it, or a sharp drop in pressure occurs, the hydraulic test is stopped to detect damage.

The boiler is considered to have passed the hydraulic test if there are no breaks, leaks or deformations in it. If water droplets appear in the welds or pipe walls or they fog up, the boiler is considered to have failed the test. Boilers that have passed the hydraulic test can be bricked up and thermal insulation work can be performed on them.

Permission to operate the boiler, superheater and economizer is issued on the basis of the results of the technical examination.

The technical examination of pipelines consists in checking the installation documentation, external examination and hydraulic testing of the installed pipelines. The technical examination of the installed pipelines is carried out by the controller engineer of the USSR Gospromatomnadzor, pipelines that are not subject to registration with the USSR Gospromatomnadzor bodies - the installation site management with the participation of a representative of the customer's technical supervision.

External inspection and hydraulic testing of pipelines from seamless pipes is allowed if they are already insulated and welded joints and flange connections are available for inspection. Pipelines made of welded pipes are subjected to a hydraulic test before thermal and anticorrosive insulation is applied to them. Welded joints are subjected to heat treatment prior to hydraulic testing.

Hydraulic testing of installed pipelines is carried out to check the strength and tightness of their connection. Before testing large-diameter pipelines, it is checked whether the supports and suspensions can withstand the additional load from the weight of water, which will be significant for large pipe diameters. In addition, attention is paid to the protection against additional bending forces of fragile lens compensators and cast iron fittings.

For supply pipelines, the working pressure is taken as the pressure developed feed pumps with closed valves.

When preparing a pipeline for a hydraulic test, the following is checked: whether welding work and heat treatment of welded joints are completed; whether gaskets are supplied in flange connections and whether they are tightened. Then, a scheme of the tested pipeline is assembled and, after checking the serviceability of the hydraulic press, it is connected to a water supply source, and the pressure pipe is connected to the tested pipeline. There must be a drain valve at the lowest point of the test section to empty the pipeline after the test, and at top point- an air cock to remove air during filling with water. A serviceable sealed pressure gauge is installed on the discharge pipeline, the verification period of which has not expired. When testing pipelines and vessels, proven spring pressure gauges with an accuracy class of at least 1.5 and a case diameter of at least 150 mm are used.

The assembly of the circuit for testing consists in the fact that the pipeline under test is disconnected from the existing or unmounted pipelines and equipment and all shut-off devices in the test section are opened, except for the valves on the drainage and drain lines, which must be closed. If the pipeline has safety valves, plugs are installed between them and the pipeline.

For hydraulic testing of pipelines, hydraulic pumps with electric drive and manual hydraulic presses are used.

The pipeline is slowly filling up raw water at a temperature not lower than the ambient temperature, as this will prevent it from sweating. At the same time, the air vents open completely. After removing the air, the air vent is closed and the pressure is gradually increased to the test one, keeping it for 5 minutes, then the pressure is reduced to the working one. Further, at operating pressure, welded and flanged joints are examined. During inspection, the welded joints are tapped with a hammer and made sure that there are no leaks, cracks, fistulas and other defects. If defective places are found, they are marked with chalk so that after the pressure is removed, they can be easily detected. Defective places in the welds are removed and re-welded. It is not allowed to correct defects before the pressure is reduced to zero.

Flanged joints and gland seals in which a leak was detected are disassembled, the cause of the leak is identified and eliminated. After elimination of defects, the hydraulic test is repeated.

The results of the hydraulic test are considered satisfactory if no pressure drop has occurred (verified by the pressure gauge) and if no leaks or sweating are found in welds, pipes, fittings and fittings. A hydraulic test cannot be performed at a negative ambient temperature, as this may defrost and break fittings, especially cast iron, and small pipes. For the same reason, from pipelines to winter time in unheated premises at the end of the hydraulic test, immediately and carefully drain the water. Areas that do not have a free drain (coils, concave areas) are blown compressed air To drain water next to the cast-iron fittings, flange connections are dismantled. When the water is lowered, the air vents open.

The results of the inspection of pipelines and permission to put them into operation are recorded in the passport.

Installation of boilers - Hydraulic testing of boilers and pipelines

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3. Hydraulic testing of boilers.

To check the strength of the structure, the quality of its manufacture, all elements of the boiler, and then the boiler as an assembly, are subjected to hydraulic tests with test pressure ppr. Hydraulic tests are carried out at the end of all welding work, when insulation and protective coatings are still missing. The strength and density of welded and rolling joints of elements is checked by test pressure pp = 1.5pp, but not less than pp + 0.1 MPa (pp is the working pressure in the boiler).

The dimensions of elements tested with a test pressure of pp + 0.1 MPa, as well as elements tested with a test pressure higher than indicated above, must be subjected to a verification calculation for this pressure. In this case, the stresses should not exceed 0.9 of the yield strength of the material σts, MPa.

After the final assembly and installation of fittings, the boiler is subjected to a final hydraulic pressure test pp = 1.25pp, but not less than pp + 0.1 MPa.

During hydraulic tests, the boiler is filled with water and the working water pressure is brought to the test pressure ppr with a special pump. The test results are determined by visual inspection of the boiler. As well as the rate of pressure drop.

Steam boilers after being installed on the ship must be subjected to a steam test at operating pressure, which consists in the fact that the boiler is driven in operational condition and tested in operation at operating pressure.

Gas cavities of utilization boilers are tested with air at a pressure of 10 kPa. Gas ducts of auxiliary and combined PCs are not tested.

4. External inspection of steam boilers.

External inspection of the boilers complete with apparatus, equipment, service mechanisms and heat exchangers, systems and pipelines is carried out under steam at operating pressure and, if possible, combined with a test of the operation of the ship's mechanisms.

The condition of the equipment, the serviceability of the drives, the absence of steam, water and fuel leaks in glands, flanges and other connections should be checked.

Safety valves must be tested in operation for operation. The valves must be adjusted to the following pressures:

Rotkr ≤ 1.05 Pwork for Pwork ≤ 10 kgf/cm2;

Rotkr ≤ 1.03 Pwork for Pwork > 10 kgf/cm2;

The maximum allowable pressure during the action of the safety valve Pmax ≤ 1.1 Rrab.

The safety valves of superheaters must be adjusted to operate with some advance of the boiler valves.

The operation of the manual actuation of the safety valves shall be checked.

With positive results of external examination and verification in operation, one of the boiler safety valves must be sealed by the inspector.

If it is not possible to check the safety valves on the disposal boilers in the parking lot due to the need for long-term operation of the main engine or the impossibility of supplying steam from the auxiliary fuel-fired boiler, then the adjustment and sealing of the safety valves can be checked by the shipowner during the voyage with the issuance of the relevant act.

During the survey, the operation of the automatic control systems of the boiler plant should be checked.

You should also check the operation of the boiler installation when changing from automatic to manual control and vice versa.

If during the external examination defects are found, the cause of which cannot be established by this examination, the inspector may require an internal examination or hydraulic test.

studfiles.net

types, technical examination and diagnostics of equipment

For the normal functioning and efficient use of boilers and units that heat water, it is imperative to carry out operational and adjustment tests of hot water boilers. The essence of such tests is to choose the most optimal modes operation of equipment that is involved in the heating system. Content

Regime and adjustment tests of hot water boilers

Tests should be carried out after the installation of all equipment, completion of installation of commissioning mechanisms, as well as after appropriate training of workers in the correct and safe operation mechanisms and units of this system.

Regime and adjustment work should be carried out after installation or repair of the boiler. In exceptional cases, such work may also be carried out during the operation period.

Regime and adjustment tests of hot water boilers are carried out to select best modes works, to compile a regime map and to draw up recommendations for improving the efficiency of equipment.

In the process of setting up the units, fuel consumption, flow rate, pressure, fuel combustion temperature and some other parameters are checked. physical process fuel combustion.

Hot water boilers are installed for space heating. Their main advantage is that they can be installed wherever central heating is absent.

Read more about wood-fired boilers here.

After the necessary work calculations are carried out to determine the minimum and maximum performance efficiency of the boiler house.

The main objectives of such events are: familiarization with the data of the registration certificate and the operation of the unit, drawing up a test method, drawing up a consistent program, conducting trial and preparatory work, carrying out the main work, calculating the results and compiling a report and regime maps.

Regime and adjustment measures should be carried out: for boilers on liquid and solid fuels - 1 time in 5 years; for gas boilers - 1 time in 3 years.

Mode tests

Mode tests of water-heating units are carried out to install an energy-saving method that does not require large cash costs.

These activities are also called environmental and thermal engineering. During the adjustment, shortcomings in the operation of the entire water heating system are revealed.

After receiving all the necessary data, it is developed integrated system to improve the efficiency of the devices.

The need for routine adjustment of boilers:

detection and elimination of defects of all equipment;
minimizing the release of toxic gases into the atmosphere;
increase in the efficiency of the heating device;
increase the service life of the mechanisms and units of the system;
examination performance characteristics of the entire water heating installation, declared in the documentation of the manufacturer and the technical passport of the equipment.

Mode tests of solid fuel boilers are carried out 1 time in 5 years, and gas - 1 time in 3 years.

The advantages and benefits of a heating water boiler are beyond doubt, but like any technical means, boilers periodically need maintenance.

How to correctly calculate power gas boiler read here.

Technical certification of water heating devices

Technical examination (TO) of hot water boilers and hot water equipment is carried out in order to check the operability of all mechanisms and to avoid accidents due to technical reasons.

Maintenance can be carried out in two ways - visual and hydraulic. With visual - internal and external inspection is carried out. With hydraulic - the boiler must be under test pressure for several minutes.

A hydraulic test must be carried out only after the internal and external tests have been carried out.

Technical examinations are carried out: primary - the first time before the boiler is put into operation; periodic - once every eight years for control, and extraordinary - at the end of the service life, in case of accidents or explosions, after natural disasters. Such events are carried out only by an organization licensed by Gostekhnadzor, specialists and special equipment.

The purpose of testing hot water boilers is to determine the actual operational, thermal and environmental performance.

See the diagram of the hot water boiler here.

For a qualitative inspection of water heating installations, work should be carried out in the following sequence:

examination technical documentation and drawing up a maintenance action plan;
conducting an external examination and measuring all the necessary parameters;
grading technical condition all equipment.

The technical condition of the boiler is checked once every 5 years, and hydraulic tests and measurement of the geometric dimensions of the unit are carried out once every 10 years.

Technical diagnostics of hot water boilers

Technical diagnostics of water heating devices is carried out for the purpose of safe operation of mechanisms. In the event of a defect, accident or expiration of the service life - to determine the limit service life.

Such a procedure can be carried out only by those public and private organizations that have permission from Gostekhnadzor and with the availability of specialists and equipment for diagnosing.

Procedure for diagnosing heating devices:

breeding hot water device from work, cooling and disconnection from other units.
Cleaning of soot inside and outside those surfaces on which diagnostics should be carried out.
If necessary, the insulation and lining of the walls are removed and internal organization boiler to ensure technical diagnostics.

Hot water waste heat boilers are designed for cooking hot water industrial and household purposes with a maximum design temperature of up to 115°C.

Read more about electric hot water boilers here.

The diagnostic devices used must be equipped with non-destructive testing elements that can accurately determine the presence of a defect, its location and size.

To measure parameters such as pipe deflection, diameter, deflections and sags of drums, special tools must be used that determine all dimensions to the nearest mm. To measure the wall thickness, it is necessary to use linear instruments that have an error of no more than 0.1 mm.

Technical diagnostics of metal and welds should be carried out with tools that have passed state testing and meet accepted standards.

Diagnosis should be carried out 1 time in 4 years.

Technical examination, diagnostics and operational and adjustment tests of hot water boilers and hot water equipment - a guarantee of the safe operation of the units, extension of the service life, concern for human health and avoidance of pollution environment toxic gases and dust.

kotlotech.ru

Steam boiler testing. Hydraulic testing of a steam boiler after repair

Hydraulic tests of boilers are carried out after completion of all welding work and before installing insulation and applying protective coatings. When testing for strength and density, taps and valves (spring) are blocked or muffled. The boiler is filled with water at a temperature not lower than plus 70C. And not higher than 40-500 C. The temperature in the boiler room should not be lower than + 50C. Pressure builds up hand pump with check on the control manometer. The pressure rise time is 10-15 minutes. Inspection is carried out at working pressure (10 min), at test pressure (5 min) and again at working pressure. If during the inspection no leaks, ruptures of welds, residual deformations and other defects are found, then the boiler is recognized as serviceable. The test results are recorded in the boiler's cord book. The value of the test pressure Ppr for boilers is set for two cases: - during manufacture or repair; - assembled with fittings. The values of test pressures depend on the type of boilers and their operating conditions. For boilers, superheaters, economizers and their elements operating at temperatures up to 3500C, the test pressure is equal to 1.5 of the operating pressure Рр, but not less than (Рр +0.1) MPa. And when assembled with fittings - 1.25Рр, but not less than (Рр +0.1) MPa. For superheaters and their elements operating at temperatures above 3500С, the test pressure is calculated by the formula:

where is the yield strength of the material at a temperature of 3500C, MPa. is the yield strength of the material at operating temperature, MPa. The feed valves of the boilers are tested for a pressure of 2.5 Pp. And gas cavities of utilization boilers - with air under pressure of 0.01 MPa. After hydraulic tests, a steam sample of the boiler is made at operating pressure. Safety valves must be adjusted to the following opening pressures (in MPa):

During steam tests, the pressure is increased in steps and with stops during which intermediate inspections are made. At operating pressure, the boiler is checked for at least 30 minutes. Mooring tests of the boiler are carried out after a steam test. Their purpose is to adjust and test in operation on a working boiler all systems, devices and automation equipment. During mooring trials, the reliability of the boiler plant is evaluated and the operating parameters are determined, as well as the thermal expansion of the boiler on the supports is controlled. The final stage is sea trials. At the same time, the reliability and safety of the operation of the entire boiler plant in certain modes are determined and comprehensive thermal engineering tests are carried out. When repairing boilers full program tests are determined by the Register. The scope of the program depends on the category of the repair being carried out.

morez.ru

Hydraulic tests of boilers test their strength

When dealing with any thermal equipment, regardless of the type of fuel and design, I want to have a guarantee of its reliability, durability and quality.

Hydraulic tests of boilers are just carried out to test the entire structure for strength. All elements of the thermal system are tested separately. Then, in assembled form, hydraulic tests of the boilers as a whole are carried out.

The test is carried out upon completion of welding work, when there are still no protective coatings, as well as insulation. The density and strength of rolling and welded joints are tested with a test pressure equal to 1.5 working pressures in the boiler. Stresses should not exceed the yield of the material by 0.9 of the limit.

After complete assembly and installation of all necessary fittings, the boiler is already subjected to a final test at a pressure of 1.25 from the working one. The boiler plant is filled with water. The working pressure of the water is adjusted by a special pump to the test pressure. The result of the test is determined by visual inspection of the boiler plant and by the rate of pressure reduction.

The boiler is deemed to have passed the test if there is no pressure drop and if visual inspection does not reveal bulges, leaks, changes in shape or permanent deformations. The appearance of small drops of dew in the metas of rolling joints and sweating are not leaks. The appearance of dew at the welds is unacceptable and is considered a leak.

Similar tests are carried out for all types of boilers, regardless of the model or fuel used. The purpose of hydraulic testing is to check the reliability of thermal equipment in emergency. Boilers that do not pass the hydraulic test must be rejected.

Steam boilers are also tested. The check is carried out at operating pressure when the boiler is put into operation. Air with a pressure of 10 kPa is used to test the gas cavities of the utilization boiler. Gas ducts of combined and auxiliary steam boilers are not subjected to hydraulic tests.

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Boilers hydraulic test - Encyclopedia of Mechanical Engineering XXL

The pressure to which the boiler is subjected during the test should be controlled by two pressure gauges, of which one should be control. Simultaneously with the boiler, all its fittings are subjected to hydraulic testing.

General information about the technical supervision of steam boilers external and internal inspection of the boiler hydraulic test.

The strength and tightness of all elements of the boiler working under pressure are checked after repair of the boiler by a hydraulic test for working pressure.

Hydraulic test of the boiler. A hydraulic test is carried out in order to determine the strength of the pressure elements of the boiler and the density of their joints.

The purpose of the hydraulic (pneumatic) test is to check the strength and tightness of welded joints and all elements of boilers, steam heaters, pressure vessels, as well as steam and hot water product pipelines. Subject to hydraulic test

During hydraulic tests at a permitted working pressure of more than 0.5 MPa, the test pressure should be 1.25 working pressure, with a permitted pressure of more than 0.5 MPa - 1.5 working pressure. Typically, hydraulic tests are carried out at a positive temperature of at least 15 ° C when air is removed from the vessel or boiler. The pressure rise time should be at least 10 minutes and rise smoothly. The exposure time in this case is at least 20 minutes. After that, the pressure is reduced to the working one and the welds are inspected. Sometimes a phosphor is added to the liquid and the surface is examined under ultraviolet light. The surface itself is coated with indicator substances for better detection of leaks (starch, etc.).

Each boiler unit is subject to technical examination by an inspector of Gosgortekhnadzor. External inspection is carried out at least once a year, internal - at least once every three years, hydraulic pressure test (working plus 3 bar) - at least once every six years. An extraordinary survey is carried out after a major repair of the boiler elements operating under pressure.

In gas, gas-oil and dust-gas burners, welds of gas elements, in addition to technical inspection and measurements, are subjected to a hydraulic strength test with an overpressure of 1 MPa and a density (tightness) test with kerosene according to GOST 3285-77. gas elements burners are also subjected to a leak test when installed together with a gas pipeline within the boiler in accordance with the requirements of the Safety Rules in the gas industry>.

Elements of factory and assembly blocks are exposed to intense oxygen corrosion after their hydraulic testing at boiler plants and assembly sites, as well as in assembly. The water remaining in them after this operation is often the cause of serious ulcerative lesions of the metal of the boilers before they are put into operation. Long term storage blocks on the installation site without their conservation also leads to dangerous corrosion before the boiler is installed.

When conducting hydraulic tests of the boiler at the end of the repair, the tract is filled without first draining the preservative solution. Before putting the boiler into operation, the solution is drained from all drained sections, its residues are displaced by condensate through the appropriate drains and the drainage tank, and from there they are sent to the waste water pit for neutralization. Washing the circuit is carried out until the content of hydrazine after the boiler is not more than 3 M g/kg, and the pH of the condensate is not more than 9.5.

It is advisable to perform hydraulic testing of boiler drums with inhibited water of the same composition as is used for pressure testing of pipe

Hydraulic tests of a number of corroded T rub showed their reduced mechanical strength some pipes were leaking at a pressure not exceeding the working pressure in the boiler. By etching defective pipes in a 10% hydrochloric acid solution, a weak corrosion resistance of the metal located under the shells was established.

As examples in Fig. Figures 1-6 and 1-7 show the screen block of the rear wall of the B-50-40 boiler furnace and the superheater block. Screen units up to 3 wide are supplied as finished heating surfaces with top and bottom chambers hydraulically tested at the factory.

Each hollow casting must be subjected to a hydraulic test pressure test in accordance with GOST 356-80. Hydraulic testing of castings that have undergone complete control by radiography or ultrasound at the manufacturer of castings can be combined with hydraulic testing of a boiler element or pipeline with a test pressure established by the NTD for the element or object.

Non-ferrous metals and alloys in boilers and pipelines are of limited use for the manufacture of small sizes of valves and instrumentation, and therefore the Rules for boilers and pipelines do not contain such detailed requirements for them as for steel and cast iron. The use of bronze and brass for parts of boilers and pipelines is permissible at a metal temperature not exceeding 250 ° C. The test pressure of hydraulic testing of valve bodies must comply with the requirements of GOST 356-80.

Regular processing of daily graphs of steam temperature behind each boiler (at a steam temperature of 450 C and above) allows you to timely take into account the operating time when the steam temperature exceeds the nominal one. During repairs, as well as when stopping the boilers for hydraulic testing, a thorough inspection of the pipes of the heating surfaces and their welded joints is carried out to identify pipes with large residual deformation, corrosion, ash wear, cracks in welded joints, unacceptable ovality and other defects. These data are analyzed by the metal laboratory, which also monitors

The purpose of the hydraulic test is to check the strength and density of welded joints, as well as all elements of boilers, superheaters, economizers, pressure vessels, and steam and hot water pipelines. Subject to hydraulic test

Hydraulic testing of boilers, superheaters, 39-959 609

All pipes for high and supercritical pressure boilers undergo a hydraulic pressure test, determined by the formulas

Control of welded joints of steam boilers and pipelines is carried out by external examination mechanical testing of samples cut from control plates, from control joints of pipes or from the products themselves; X-ray or gamma-ray transmission; ultrasonic flaw detection; macro- and microstructure studies; and hydraulic testing.

The calculation of steam boiler elements for strength should provide such dimensions of the calculated elements at which the stresses arising during operation and during hydraulic tests would not lead to residual shape distortions or to destruction.

Hydraulic testing of steam and hot water boilers

The boilers are subjected to a hydraulic test after their installation on the foundations, when the lining has not yet been made, all parts of the boilers are available for inspection and the boilers are not connected to the systems.

Hydraulic testing of vertical water-tube steam boilers is carried out before they are bricked up.

Based current rules Boiler supervision hydraulic testing of steam boilers with a working pressure above 0.7 atm is carried out according to table. 26.

Hydraulic testing of the boiler must be carried out with fittings installed on it.

Prior to the installation of the superheater in the coils, the absence of visible external defects is checked for the conformity of the outer diameters and wall thicknesses steel pipes design dimensions ovality of pipes of coils, regularity of bends and permeability of coils, as well as their tightness. The tightness is checked by hydraulic testing of each coil individually for a pressure exceeding the operating pressure of the boiler by 1.25 times.

After installation and alignment of the drums, work is carried out on rolling and assembling the boiler and screen pipes. They install the intra-drum equipment and fittings and test the boiler with hydraulic pressure. After a hydraulic test, the laying of the boiler lining is carried out.

Before assembly, all finned tubes and rolls are subjected to a hydraulic pressure test equal to 1.25 p 4-5 atm (where p is the operating pressure of the boiler in atm).

Hydraulic testing of butt-welded pipes is carried out at a pressure of 2p + 11 atm using devices for individual pressure testing (p is the working steam pressure in the boiler)

The change of rivets is carried out only with the knowledge and permission of the Gosgortekhnadzor inspection. When replacing more than 15 adjacent rivets, an extraordinary hydraulic test of the boiler with the participation of a representative of the Gosgortekhnadzor inspection is mandatory.

An internal inspection is carried out at least once every 4 years. When it is performed, first of all, the boiler drum is inspected from the inside. Hydraulic testing of the boiler for strength and density of its elements is carried out at least every 8 years. Hydraulic and testing is always preceded by an internal inspection. The test is carried out by raising the pressure above the working one in a boiler filled with water in order to check its strength and density. The results of the survey are recorded in the passport of the boiler unit.

Upon completion of the repair work, the commission checks the acts of operational acceptance, internal inspection of the boiler drums, hydraulic testing, checking the safety fittings of the boiler and devices. Based on the test results of the boiler and the listed documentation, an act of general acceptance of the boiler from the overhaul is drawn up.

When installing the boiler block not on the foundation, but on the laying of the brickwork, an additional lifting of the assembled boiler will be required in this case, the installation sequence will change somewhat and will consist of the following stages of installing the boiler block on the foundation of the installation on temporary extensions of the side walls of the boiler piping frame and side platforms of the ladders for installing fittings installation of a cast-iron partition (if it was not mounted in the block) lifting the boiler block and installing it on temporary support trestles completion of assembly of the framing frame, platforms and ladders laying out the lining to the design mark of the bottom of the boiler support frame installation of the boiler block on the laying of the lining alignment of the installed boiler block pouring cement of the support frame of the steam superheater installation installation of intra-drum devices and a blowing device production of brickwork above the mark of the sole of the support frame of the boiler hydraulic testing of the boiler its pro alkalization and testing for vapor density.

qpeAax used for hydraulic testing must be free of oily and suspended solids. To eliminate corrosion of boiler elements made of pearlite steel, it is advisable to add one of the following mixtures of inhibitors to water [L. 24]

For anti-corrosion protection of internal surfaces of screen coils and steam heaters during their transportation and storage at the boiler plant after a hydraulic test, a volatile inhibitor is introduced into them, and their ends must be sealed with polyethylene caps. The outer surface of these parts of the boiler must be protected

During hydraulic testing of boilers, vessels and pipelines, their strength and density are checked. However, in cases where increased requirements are imposed on the tightness of products, a pneumatic leak test is carried out using one of the following aquarium methods for washing the pressure drop of halogen leak detectors with a mass spectroscopic hot environment of stable traces of pressure increase in the pressure chamber.

For MTO of metal pipes, heating piping and steam boiler piping, it was proposed to use a hydraulic test with increased pressure. However, this raises a number of difficulties. For the implementation of the MTO, the plastic deformation should be 0.5-27o- However, the tolerance for the wall thickness of the pipes reaches 20-25%. The pipes of heating surfaces have different safety margins at low temperatures, since, for example, an economizer is calculated according to the yield strength at a maximum operating temperature of up to 250-300 ° C, and a superheater is calculated according to the long-term strength at operating temperatures. The yield strength of steel of the same grade may fluctuate according to specifications within a very wide range. If a

It should be noted that only the reduction of the inverse balance of the boiler makes it possible to quantitatively identify heat losses and related shortcomings in its operation and outline ways to eliminate them. Therefore, this method is in many cases preferred, although it gives less accurate results in determining the efficiency of the boiler. Often tests are carried out on a forward and reverse balance. This combination is the most acceptable, as it allows you to get a complete picture, both qualitative and quantitative. Apparently, there is no need to give formulas for determining heat losses with exhaust gases, with chemical underburning, etc. . Currently, there is no approved uniform methodology thermotechnical tests contact economizers. The scope and nature of the measurements depend on the tasks involved. The most common types of tests are thermotechnical, aerodynamic and thermochemical, carried out when performing commissioning. The purpose of these tests is to determine the possible temperature of heating water and outgoing flue gases, maximum heat output without replacing the smoke exhauster, maximum performance on water while maintaining normal hydraulic mode and the absence of a noticeable entrainment of water into the gas ducts. At the same time, studies of the quality of heated water are usually carried out simultaneously and changes in its composition, in particular, corrosion activity, are studied. Such tests necessarily accompanied the commissioning of the first industrial contact economizers.

Transportation of the boiler on dirt and paved roads is carried out by tractor traction using special sledges or carts. The boiler montale, upon receipt of it in assembled form, is produced in the following order; the boiler block received from the manufacturer is dragged and installed on the foundation; cement mortar installation of the strapping frame, scaffolds and ladders installation of reinforcement installation hydraulic testing of the boiler installation cast iron partition install an intra-drum device and a blowing device, carry out brickwork, alkalize the boiler and test it for steam density.

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Hydraulic testing of boilers carried out after completion of all welding work and before installation of insulation and application of protective coatings. When testing for strength and density, taps and valves (spring) are blocked or muffled. The boiler is filled with water at a temperature not lower than plus 70C. And not higher than 40-500 C. The temperature in the boiler room should not be lower than + 50C. The pressure is created by a hand pump with a check on the control pressure gauge. The pressure rise time is 10-15 minutes. Inspection is carried out at working pressure (10 min), at test pressure (5 min) and again at working pressure. If during the inspection no leaks, ruptures of welds, residual deformations and other defects are found, then the boiler is recognized as serviceable. The test results are recorded in the boiler's cord book.
The value of the test pressure Ppr for boilers is set for two cases: - during manufacture or repair; - assembled with fittings. The values of test pressures depend on the type of boilers and their operating conditions. For boilers, superheaters, economizers and their elements operating at temperatures up to 3500C, the test pressure is equal to 1.5 of the operating pressure Рр, but not less than (Рр +0.1) MPa. And in assembled form with fittings - 1.25Rp, but not less than (Rp +0.1) MPa.
For superheaters and their elements operating at temperatures above 3500C, the test pressure is calculated by the formula:

where is the yield strength of the material at a temperature of 3500C, MPa.
is the yield strength of the material at operating temperature, MPa.
The fittings of the boilers are tested for double working pressure, during tests for tightness of closing - at a pressure of 1.25 Pr. The feed valves of the boilers are tested for a pressure of 2.5 Pp. And gas cavities of utilization boilers - with air under pressure of 0.01 MPa.
After hydraulic testing, a steam sample of the boiler is made at operating pressure. Safety valves must be adjusted to the following opening pressures (in MPa):

During steam tests, the pressure is increased in steps and with stops during which intermediate inspections are made. At operating pressure, the boiler is checked for at least 30 minutes.
Mooring tests of the boiler are carried out after the steam test. Their purpose is to adjust and test in operation on a working boiler all systems, devices and automation equipment. During mooring tests, the reliability of the boiler plant is evaluated and the operating parameters are determined, as well as the thermal expansion of the boiler on the supports is controlled.
The final stage is sea trials. At the same time, the reliability and safety of the operation of the entire boiler plant in certain modes are determined and comprehensive thermal engineering tests are carried out.
When repairing boilers, the full test program is determined by the Register. The scope of the program depends on the category of the repair being carried out.

K category: Boiler installation

Hydraulic testing of boilers and pipelines

In accordance with the rules of the USSR Gospromatomnadzor, boilers, superheaters and water economizers operating under an overpressure of more than 0.07 MPa, as well as hot water boilers with a water heating temperature above 115 ° C, are registered with the USSR Gospromatomnadzor bodies and subjected to technical examination.

The technical examination consists of an internal inspection and a hydraulic test of the units. Superheaters and economizers, constituting one unit with the boiler, will be examined simultaneously with it.

The boiler is inspected inside, checking for cracks, ruptures, metal corrosion, violations of rolling and welded joints and other possible defects.

A hydraulic test is performed to check the strength of the pressurized elements of the boiler and the tightness of their connections. Drums and chambers of steam boilers, screen and convective pipe systems, superheaters and water economizers are subjected to hydraulic testing. Hydraulic tests of individual elements and blocks, carried out on an enlarged assembly site, do not exempt the installed equipment from hydraulic testing.

The boiler unit is inspected at operating pressure, tapping the welds with light blows of a hammer weighing no more than 1.5 kg. Particular attention is paid to the density of welds, rolling and flanged joints. If, when testing the boiler, shocks, noise, knocking are heard inside it, or a sharp drop in pressure occurs, the hydraulic test is stopped to detect damage.

Permission to operate the boiler, superheater and economizer is issued on the basis of the results of the technical examination.

For feed pipelines, the pressure developed by the feed pumps with closed valves is taken as the working pressure.

When preparing a pipeline for a hydraulic test, the following is checked: whether welding work and heat treatment of welded joints are completed; whether gaskets are supplied in flange connections and whether they are tightened. Then, a scheme of the tested pipeline is assembled and, after checking the serviceability of the hydraulic press, it is connected to a water supply source, and the pressure pipe is connected to the tested pipeline. At the lowest point of the test section there must be a drain valve to empty the pipeline after the test, and at the highest point - an air cock to remove air during filling with water. A serviceable sealed pressure gauge is installed on the discharge pipeline, the verification period of which has not expired. When testing pipelines and vessels, proven spring pressure gauges with an accuracy class of at least 1.5 and a case diameter of at least 150 mm are used.

The assembly of the circuit for testing consists in the fact that the pipeline under test is disconnected from the existing or unmounted pipelines and equipment and all shut-off devices in the test section are opened, except for the valves on the drainage and drain lines, which must be closed. If there are safety valves on the pipeline, plugs are installed between them and the pipeline.

For hydraulic testing of pipelines, hydraulic pumps with electric drive and manual hydraulic presses are used.

The pipeline is slowly filled with raw water at a temperature not lower than the ambient temperature, as this will prevent it from sweating. At the same time, the air vents open completely. After removing the air, the air vent is closed and the pressure is gradually increased to the test one, keeping it for 5 minutes, then the pressure is reduced to the working one. Further, at operating pressure, welded and flanged joints are examined. During inspection, the welded joints are tapped with a hammer and made sure that there are no leaks, cracks, fistulas and other defects. If defective places are found, they are marked with chalk so that after the pressure is removed, they can be easily detected. Defective places in the welds are removed and re-welded. It is not allowed to correct defects before the pressure is reduced to zero.

Flanged joints and gland seals in which a leak was detected are disassembled, the cause of the leak is identified and eliminated. After elimination of defects, the hydraulic test is repeated.

The results of the hydraulic test are considered satisfactory if no pressure drop has occurred (verified by the pressure gauge) and if no leaks or sweating are found in welds, pipes, fittings and fittings. A hydraulic test cannot be performed at a negative ambient temperature, as this may defrost and break fittings, especially cast iron, and small pipes. For the same reason, water is immediately and thoroughly drained from pipelines in unheated rooms after the end of the hydraulic test. Areas that do not have a free drain (coils, concave sections) are blown with compressed air. To drain water, flange connections are dismantled near the cast-iron fittings. When the water is lowered, the air vents open.

The results of the inspection of pipelines and permission to put them into operation are recorded in the passport.

- Hydraulic testing of boilers and pipelines

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