RU2796250C1 - Method for carrying out pneumatic airtightness tests of three degrees of protection of the lower drain device of an oil and petrol tank car - Google Patents

Abstract

FIELD: testing devices.

SUBSTANCE: invention is related to a device of testing products for airtightness and can be used to test the airtightness of three degrees of protection of the lower drain device of an oil and petrol tank car (16), namely: the main valve (15), an additional locking device (13) and a lower safety lid (6). Compressed nitrogen is supplied from cylinders (10) to a controlled lower drain device of an oil and petrol tank car (16). The pressure of the compressed gas is increased to 0.28-0.32 MPa. The controlled device is maintained under a given pressure for 3 minutes. To determine the leakage, the pressure of the compressed gas is controlled using the pressure sensor (2) installed in the pipeline (9). Gas is discharged from the bottom drain device through the tap (4).

EFFECT: simplification and reduction of test time.

1 cl, 4 dwg

Description

The invention relates to the field of railway transport and can be used in leak testing of products of various sizes for the oil and gas industry, including when preparing for loading an oil and petrol tank car with a lower drain device having different degrees of protection.

Known Installation for pneumatic testing of boilers of tank cars during overhaul and depot repairs, including a device for creating pressure with a pressure sensor, configured to be connected to the tested capacity, and a control and display unit, while the device for creating pressure is made in the form of a mobile unit , containing connecting sleeves with quick-release connections for connecting the mobile unit to the depot pneumatic line and the test object, pressure gauges installed on the inlet and outlet pipes of the mobile unit and designed to display the pressure in the depot pneumatic line and test voltage, filters installed in series in the inlet pipe of the PU mobile unit and intended for cleaning and drying the air coming from the depot pneumatic line, electro-pneumatic valves for transferring the air flow from the depot pneumatic line to the test object in the required volume, air flow amplifier, pressure regulator, while it is equipped with a technological plug of the safety inlet valve, a technological drain plug instrument and the tester's workplace, and the control unit is equipped with a radio modem (RF patent No. 87015, G01M 3/00, G01M 3/26, publ. September 20, 2009).

The disadvantage of using this installation for testing a tank car is the possibility of testing with its help only two degrees of protection: the main valve and an additional locking device, while the lower safety cover is not tested.

Known Method for hydraulic (pneumatic) testing of pressure vessels (pipelines), in which pressure vessels (pipelines) are periodically loaded with liquid or gas test pressure exceeding the operating operating pressure, maintained under test pressure, after which the pressure is reduced and the vessels are inspected (pipelines) pressure, while they are considered to have passed the hydraulic (pneumatic) tests, if during the tests and during the inspection no leaks and / or metal ruptures were found, during the holding process the pressure drop did not go beyond the established limits, and after the tests no new residual deformations, while the test mode is chosen so that the sizes of cracks of a family of cracks of a critical size corresponding to the test mode are less than the sizes of cracks of a family of cracks of a critical size corresponding to the operating mode of operation, the test frequency is chosen such that the time between hydraulic (pneumatic) tests does not exceeded the time of increase in the size of cracks of a family of cracks of critical size corresponding to the mode of hydraulic (pneumatic) tests to the sizes of cracks of a family of cracks of critical size corresponding to the operating mode (RF patent No. 2243523, G01M 3/12, G01M 3/00, publ. December 27, 2004).

The disadvantages of this method are:

- the need to inspect the object after testing for ruptures and residual deformations, since the NSU valve and shutter are difficult to access for inspection, and their preliminary check is carried out by touch;

- the need to determine the test mode for each NSU depending on the size of the cracks, which is complicated by the inaccessibility of the internal elements of the controlled device for visual inspection and assessment of the size of the cracks;

- increased test duration, due to the need to establish the presence of cracks in the test object and analyze them to select the test mode, which does not meet the requirements of the current technological documents, where preparation for loading one tank is no more than 17 minutes, including testing the controlled device.

Known Method for monitoring the tightness of containers, including measuring the pressure and temperature of the sample gas in the tank at the initial time and continuous measurement of the pressure and temperature of the gas for a given time interval, the tightness at any time is judged by the value of the criterion of tightness (RF patent No. 2298774, G01M 3/00, published on May 10, 2007).

The disadvantages of this method are:

- the need for continuous measurement of temperature and pressure in the controlled device when using an additional device for measuring the temperature of the sample gas, which, due to design features, cannot be placed inside the controlled device;

- increased duration of testing due to continuous measurement of temperature and pressure in the hull of the NSU and the performance of relevant calculations, which does not meet the requirements of current technological documents, where preparation for loading one tank is no more than 17 minutes, including testing of a controlled device.

A known method for testing a container for leaks, including installing a pressure sensor, supplying gas to a controlled device, raising the gas pressure to a predetermined value, maintaining a controlled device at a given pressure for a predetermined time and controlling the pressure value to determine gas leakage, gas discharge (RF patent No. 2710006, G01M 3/02, G01M 3/26, G01M 3/32, published 12/23/2019, prototype).

The disadvantages of this method are:

- Mandatory operations of temperature stabilization in the test unit;

- increased duration of tests due to the performance of calculations, which does not meet the requirements of current technological documents, where preparation for loading one tank is no more than 17 minutes, including testing of a controlled device.

The technical solution is to improve the quality of the preparation of an oil and petrol tank car for loading by ensuring the tightness of the seals of all three degrees of protection of the lower drain device: the main valve, the additional locking device and the lower safety cover, as well as ensuring that the standard time for performing the technological operation to check the tightness of the lower drain devices and facilitating the process of checking the tightness of the lower drain device.

Ensuring the tightness of all three degrees of protection of the lower discharge device improves the quality of preparation of the oil and petrol tank car for loading and is the key to the safety of the transported cargo, ensuring the safety of train traffic and environmental standards, since otherwise oil products may spill onto the railway tracks through the lower discharge device.

The stated technical result is solved due to the fact that the Method for carrying out pneumatic testing of the tightness of three degrees of protection of the lower drain device of an oil and petrol tank car includes installing a pressure sensor, supplying gas to the controlled device, raising the gas pressure to a predetermined value, maintaining the controlled device at a predetermined pressure for set time and pressure value control to detect gas leakage, gas discharge, and the gas is compressed nitrogen, the controlled device is the bottom drain device of the oil and gas tank car, the pressure sensor is installed and fixed in the pipeline for the test medium after the locking elements with the ability to control pressure, the lower drain device is equipped with a tip, a safety cover, a screw located in the safety cover, sealing elements and an annular insert, which is installed between the tip and the safety cover before compressed nitrogen is supplied and which is clamped by tightening the screw, the pressure of compressed nitrogen in the lower drain device is increased until a value of 0.28-0.32 MPa is reached, the lower drain device is maintained at a given pressure for 3 minutes, after which compressed nitrogen is discharged from the lower drain device.

In FIG. 1 shows a diagram of a device with which the claimed method is implemented, in Fig. 2 is a left side view of the connections: a pressure rubber hose with a pipeline for the test medium with a valve, a cock and a pressure sensor and a pipeline for the test medium with a compressed nitrogen supply line, in FIG. 3 shows the rear view of the connections: a pressure rubber hose with an annular insert with a sealing element and a pipeline for the test medium with a valve, a cock and a pressure sensor, in fig. 4 shows a front view of the lower drain device in the process of installing an annular insert with a sealing element into it and clamping it with a screw.

This method is implemented by the device using the following notation:

1 - ring insert;

2 - pressure sensor;

3 - valve;

4 - crane;

5 - pressure rubber sleeve;

6 - safety cover;

7 - compressed nitrogen supply line;

8 - tip;

9 - pipeline for the test environment;

10 - cylinders with compressed nitrogen;

11 - screw;

12 - rod of the main valve;

13 - additional locking device;

14 - loading hatch of an oil and petrol tank car;

15 - main valve;

16 - oil and petrol tank car.

The method for conducting pneumatic tightness tests of three degrees of protection of the lower drain device of an oil and petrol tank car (hereinafter referred to as the "Method") is carried out using, among other things, a controlled device, which is a lower drain device (hereinafter referred to as "NSU") of an oil and petrol tank car - tanks:

oil and petrol wagon - tank is equipped with NSU.

The NSU is equipped with an annular insert 1, a safety cover 6, sealing elements, a main valve 15, a screw 11 installed in the safety cover 6, an additional locking device 13 and a tip 8.

The annular insert 1 is suitable for various modifications of a controlled device in the form of an NSU, hermetically fixed in an oil and petrol tank car operated on the railway network of the Russian Federation, which simplifies and reduces the cost of preparatory operations before loading the oil and petrol tank car.

The annular insert 1 is made from a single piece of metal and machined on a lathe to the specified dimensions with the possibility of supplying compressed nitrogen into it and is a metal washer, for example, with a diameter of 234 mm and a thickness of 34 mm, with a through hole in the end made, for example, with a diameter of 10 mm, to enable the supply of compressed nitrogen. The dimensions of the annular insert 1 provide the possibility of hermetic installation in the lower drain device with subsequent clamping of the annular insert 1 by the lower safety cover 6 with the screw 11, due to the geometric parameters of the lower drain device. The annular insert 1 allows you to check the tightness of all seals of the lower discharge device and thereby improve the quality of the preparation of an oil and petrol tank car for loading.

In addition, the use of the annular insert 1 makes it possible to simplify and reduce the time of the pressure testing process when testing the lower drain device without using additional sensors directly in the controlled device, which is the LSU, and adjusting the frequency and test conditions for each of its elements.

NSU through a pressure rubber hose 5, for example, type G(IV)-10-12-23-U with a diameter of Du-12 mm and a length of 2000 mm, is connected to the pipeline for the test medium 9.

The pipeline for the test medium 9 is connected to the compressed nitrogen cylinders 10 through the compressed nitrogen supply line 7, which is a pneumatic line of the pipeline, for example, with a diameter of Du-50 mm, to ensure the supply of the test medium in the form of compressed nitrogen from the compressed nitrogen cylinders 10.

Cylinders with compressed nitrogen 10 (GOST 9293-74) in the amount of 12 pcs.

Each cylinder with compressed nitrogen 10 with a volume of 40 liters and each of which is equipped with pneumatic reducers, for example, pneumatic reducers of the BKO-50 MG type with built-in pneumatic safety valves and pneumatic manometers of the Manotom brand to ensure pressure control before and after reduction.

In the pipeline for the test medium 9, for example, with a length of 850 mm and a diameter of Du-12 mm, a pressure sensor 2 is installed and fixed, which is installed and fixed after the shut-off elements with the ability to control pressure, including in the pipeline for the test medium 9 in the process supplying compressed nitrogen through it from the compressed nitrogen supply line 7 to the NSU to determine the leakage of compressed nitrogen from it.

At the inlet of the pipeline for the test medium 9, a shut-off element is fixed in the form of a valve 4, for example, type AH30GK, for discharging compressed nitrogen and a shut-off element in the form of a valve 3, for example, type 215F-015-E71, with the possibility of supplying compressed nitrogen from the pipeline for testing medium 9 to the pressure sensor 2 and to the pressure rubber hose 5.

The annular insert 1 with sealing elements at the top and bottom is hermetically installed between the tip 8 and the safety cover 6, while the sealing elements are located at the top and bottom of the annular insert 1:

between the annular insert 1 and the tip 8 and between the annular insert 1 and the safety cover 6.

The advantages of the claimed Method in comparison with analogues is the possibility of ensuring tightness control not only of the structural elements of the NSU valve, but also of the safety cover 6, by clamping the annular insert 1 between the safety cover 6 and the tip 8 by means of the screw 11, as well as using for testing as a compressed gas nitrogen, which is due to the requirements for explosion safety when pressure testing tanks with oil residues.

In addition, the use of the annular insert 1 makes it possible to simplify and reduce the time of the crimping process when testing the NSU without using additional sensors directly in the controlled device - the NSU and adjusting the frequency and test conditions for each of its elements.

The method is carried out as follows.

The NSU is connected to the compressed nitrogen supply line 7, which is connected to compressed nitrogen cylinders 10.

NSU tests are carried out using an annular insert 1, a pressure rubber hose 5 of type G (IV) -10-12-23-U with a diameter of Du-12 mm and a length of 2000 mm, a manometer 2 of the Manotom brand for pressure control, a valve 3 of type 215F -015-E71 with test medium pipeline 9 850 mm long and DN-12 mm in diameter, valve 4 type AH30GK for the removal of compressed nitrogen.

Technological operations for checking the tightness of the main valve 15 NSU are performed in the following sequence:

1. Open the loading hatch of the oil and petrol tank car 14 and check the closure of the main valve 15 by screwing the rod of the main valve 12 to the stop.

2. Open additional locking device 13.

3. The safety cover 6 is opened by unscrewing the screw 11.

Between the tip 8 and the safety cover 6, an annular insert 1 with a sealing element is installed, which is clamped by tightening the screw 11, before compressed nitrogen is supplied to the NSU through the annular insert 1.

4. Shut off valve 4 for discharge of compressed nitrogen.

5. The valve 3 is opened and compressed nitrogen is supplied to the annular insert 1 through the through hole from the pipeline for the test medium 9 through the pressure rubber sleeve 5 from compressed nitrogen cylinders 10. The compressed nitrogen pressure is increased to the set value and until the set value of the compressed nitrogen pressure is reached in NSU within 0.28-0.32 MPa (2.8-3.2 kgf / cm ² ), pressure is measured and controlled by means of a pressure gauge 2.

After reaching the specified pressure in the NSU, valve 3 is closed and the NSU is maintained at a given pressure for a specified time - 3 minutes and with visual control of the pressure value in the NSU using pressure sensor 2, fixing the pressure drop using a pressure gauge 2 to determine the leakage of compressed nitrogen from the NSU in the form the formation of air bubbles passing through the seals and the product residue and, accordingly, determining the tightness of the seals in the NSU.

6. If there is no pressure drop in the NSU, valve 3 is closed and valve 4 is opened to discharge compressed nitrogen from the NSU into the atmosphere.

Upon reaching a pressure equal to 0 MPa (kgf / cm ² ) on the pressure gauge 2 and, accordingly, in the NSU, the annular insert 1 is removed by opening the safety cover 6 with the screw 11 and the compressed nitrogen is discharged from the NSU through the valve 4 for discharging compressed nitrogen, having previously opened it . The annular insert 1 with the sealing element is removed after the compressed nitrogen is completely removed from the NSU.

7. If there is a pressure drop on pressure gauge 2, i.e. if a leak of compressed nitrogen from the NSU is detected, its cause is established and eliminated, after which the tests are repeated in full.

8. If it is impossible to determine the cause of the leakage of compressed nitrogen of the oil and petrol tank car, it is sent for repair.

The test of the NSU at a pressure of 0.28-0.32 MPa (2.8-3.2 kgf / cm ² ) is due to the solidification of residues in an oil and petrol tank car for the transportation of viscous petroleum products, such as fuel oil, at low ambient temperatures, which can create a strong connection along the seal of the main valve 15 NSU. Further, when checking the tightness under a pressure of less than 2.8 kgf/cm ² the main valve 15 ensures tightness. However, after loading, the melted fuel oil begins to warm the main valve 15, thereby affecting the seal and reducing its tightness, which may cause leakage. Tests in the pressure range of 2.8-3.2 kgf/cm ² provide a high-quality check of the tightness of the NSU in all temperature conditions.

Technological operations for checking the tightness of the additional shut-off device in the form of a shutter 13 are similar to checking the main valve 15, with the additional shutter 13 being closed, and the main valve 15 being opened by turning the rod 12 of the main valve 15 to the stop.

Thus, the inventive method improves the quality of the preparation of an oil and petrol tank car for loading, facilitates pneumatic testing for tightness of seals, and also provides a time limit for performing these tests.

Claims (1)

A method for performing pneumatic tightness testing of three degrees of protection of the lower discharge device of an oil and petrol tank car, including installing a pressure sensor, supplying gas to the controlled device, raising the gas pressure to a predetermined value, maintaining the controlled device at a predetermined pressure for a predetermined time and with control of the pressure value for detection of gas leakage, gas discharge, characterized in that the gas is compressed nitrogen, the controlled device is the bottom drain device of the oil and petrol tank car, the pressure sensor is installed and fixed in the pipeline for the test medium after shut-off elements with the possibility of pressure control, the bottom drain device equipped with a tip, a safety cover, a screw located in the safety cover, sealing elements and an annular insert, which is installed between the tip and the safety cover before compressed nitrogen is supplied and which is clamped by tightening the screw, the pressure of compressed nitrogen in the lower drain device is increased to reach a value of 0, 28-0.32 MPa, maintain the lower drain device at a given pressure for 3 minutes, after which the compressed nitrogen is discharged from the lower drain device.

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