CN110823461A

CN110823461A - Safety valve inspection device

Info

Publication number: CN110823461A
Application number: CN201911184075.9A
Authority: CN
Inventors: 孙琦
Original assignee: SHENZHEN INSTITUTE OF SPECIAL EQUIPMENT INSPECTION AND TEST
Current assignee: Shenzhen Institute of quality and safety inspection and testing
Priority date: 2019-11-27
Filing date: 2019-11-27
Publication date: 2020-02-21

Abstract

The invention relates to a safety valve inspection device, which comprises a test container and a liquid storage tank, wherein the liquid storage tank is communicated with the inner cavity of the test container and can inject a low-temperature medium into the test container; the top of the test container is provided with a first control valve which is communicated with the inner cavity of the test container and can be connected with a tested safety valve, the inner cavity of the test container is provided with a first booster, and the first booster comprises a first heat exchange tube; a second booster is arranged outside the test container and comprises a second heat exchange tube; first heat exchange tube and second heat exchange tube end to end intercommunication form the heat transfer circulation passageway that supplies the heat transfer medium circulation, when the heat transfer medium flows through first booster inside, with the low temperature medium heat transfer in the experimental container, make its heat absorption intensification inflation, and then experimental container pressure risees to check-up the relief valve of being examined, through the setting of booster, increase low temperature medium self evaporation ability, improve experimental container speed of stepping up, shorten relief valve check-up time, improve inspection efficiency, reduce the human cost.

Description

Safety valve inspection device

Technical Field

The invention relates to the technical field of safety valve inspection, in particular to an improved safety valve inspection device.

Background

The safety valve is divided into a (general) safety valve and a low-temperature safety valve according to the working and using temperature, and the low-temperature safety valve type test is subjected to the following verification items according to the regulation of safety valve safety technical supervision regulations: and (4) detecting and checking two indexes of low-temperature setting pressure and low-temperature sealing pressure.

At present, the arrangement structure of the low-temperature safety valve detection and verification device is shown in the following figure 1.

The working principle of the existing detection and calibration device is as follows:

liquid nitrogen is fed into the test vessel 10 from a liquid nitrogen storage tank 20. Generally, the cryogenic liquid nitrogen storage tank 20 is at a certain pressure, and the test container 10 is generally at normal pressure, so that liquid nitrogen is fed from the cryogenic liquid nitrogen storage tank 20 into the test container under the driving of a certain pressure. The test vessel 10 was designed as a low temperature vessel with a vessel shell wrapped with a low temperature insulation material (non-low temperature insulation vacuum structure, single layer structure form). After the low-temperature liquid nitrogen is injected into the low-temperature test container 10, the low-temperature liquid nitrogen is changed into gas from liquid evaporation under the action of self-evaporation after absorbing certain heat, the volume of the low-temperature liquid nitrogen expands by more than 300 times, so that the pressure in the test container 10 rises until the pressure rises to a preset setting pressure of the low-temperature safety valve 40, the safety valve 40 is opened, and the detection and verification of the low-temperature setting pressure are completed; after the low-temperature safety valve 40 is opened, the safety valve 40 discharges a certain amount of low-temperature gas, the pressure of the test container 10 is reduced, and the safety valve 40 is closed; after the safety valve 40 is closed, the pressure of the test container 10 rises again because the liquid nitrogen absorbs heat and self-evaporates continuously, and when the low-temperature setting pressure (the detection is finished in the last step) is 90%, whether leakage exists is detected according to standard regulations, and the detection and verification of the low-temperature sealing pressure are finished.

The prior art has the following defects: the pressure of the test container 10 is increased by passing low-temperature liquid nitrogen through the outer wall of the test container 10 and a heat insulation material to absorb certain heat for self-evaporation, the liquid nitrogen is changed into gas from liquid evaporation, the volume is expanded, and the pressure is increased to realize the verification process. Since the test container 10 was covered with a certain insulating material, the self-evaporation of liquid nitrogen was very slow. In the test, the boosting process can be completed only in one hour generally, so that inconvenience is brought to the convenience of test operation. In addition, for safety reasons, the insulating effect (thickness) of the insulating layer is specified. In addition, the temperature of the liquid nitrogen is increased to a certain extent due to the self-evaporation of the liquid nitrogen, and the temperature is increased along with the prolonging of the time.

Summarizing the above analysis, the prior art mainly has the following problems:

1. the pressure raising speed of the test container is slow and is difficult to control;

2. the temperature of the low-temperature medium is greatly influenced by the physical property of self-evaporation, and the accurate control of the temperature cannot be realized. Even the medium temperature can only be increased, and the reduction can not be realized;

3. the low-temperature and high-pressure working environment of the test container is difficult to obtain.

Disclosure of Invention

The invention aims to provide a safety valve inspection device.

The technical scheme adopted by the invention for solving the technical problems is as follows: constructing a safety valve inspection device, which comprises a test container and a liquid storage tank, wherein the liquid storage tank is communicated with the inner cavity of the test container and can be used for injecting a low-temperature medium into the test container; the top of the test container is provided with a first control valve which is communicated with the inner cavity of the test container and can be connected with a tested safety valve,

a first booster is arranged in the inner cavity of the test container and comprises a first heat exchange tube; a second booster is arranged outside the test container and comprises a second heat exchange tube;

the first heat exchange tube is communicated with the second heat exchange tube end to form a heat exchange circulation channel for a heat exchange medium to circulate, when the heat exchange medium flows through the first booster, the heat exchange medium exchanges heat with the low-temperature medium in the test container to absorb heat, raise temperature and expand, and then the pressure of the test container is raised, so that the tested safety valve is verified.

Preferably, the output end of the second heat exchange tube is connected with the input end of the first heat exchange tube through an input pipeline, and the output end of the first heat exchange tube is connected with the input end of the second heat exchange tube through an output pipeline to form the heat exchange circulation channel;

a circulating pump, a second control valve and a first check valve are arranged on the input pipeline, and the circulating pump pumps the heat exchange medium in the second heat exchange tube into the first heat exchange tube;

and a third control valve is arranged on the output pipeline.

Preferably, the second booster further comprises one or more fans;

the fan air outlet faces the second heat exchange tube.

Preferably, the liquid storage tank is communicated with the inner cavity of the test container through an injection pipeline, and a fourth control valve, a second check valve and a fifth control valve are sequentially arranged on the injection pipeline from the liquid storage tank to the test container so as to control the flow speed and flow rate of the low-temperature medium in the liquid storage tank injected into the test container.

Preferably, the top of the test container is provided with a first thermometer, and the bottom of the test container is provided with a second thermometer for detecting the temperature difference between the upper end and the lower end of the test container;

a backflow pipe is arranged at the bottom of the test container, and a third check valve and a sixth control valve are arranged on the backflow pipe;

when the temperature difference is a first preset temperature difference, the sixth control valve is opened, and redundant low-temperature medium in the test container flows back to the liquid storage tank by utilizing the pressure difference between the test container and the liquid storage tank.

Preferably, a cooler communicated with the liquid storage tank is arranged in the test container;

and a third booster is arranged outside the test container, and two ends of the third booster are respectively connected with the liquid storage tank and the cooler.

Preferably, the desuperheater comprises a third heat exchange pipe, and an input end of the third heat exchange pipe is connected into the injection pipeline between the second check valve and the fifth control valve through a seventh control valve;

the output end of the third heat exchange tube is communicated with the liquid storage tank through a main tube, and an eighth control valve, a ninth control valve and a tenth control valve are sequentially arranged on the main tube from the third heat exchange tube to the liquid storage tank.

Preferably, the safety valve inspection device further includes a bypass pipe connected in parallel to both ends of the ninth control valve;

the third booster is arranged on the bypass pipe, the third booster comprises a fourth heat exchange pipe, and the input end of the fourth heat exchange pipe is connected to the main pipe between the eighth control valve and the ninth control valve through an eleventh control valve;

the output end of the fourth heat exchange tube is connected to the main tube between the ninth control valve and the tenth control valve through a twelfth control valve;

the ninth control valve is closed, the eleventh control valve and the twelfth control valve are opened, at this time, the low-temperature medium in the fourth heat exchange tube is subjected to heat exchange with the external atmosphere environment, the temperature is increased, the pressure in the fourth heat exchange tube is increased, the low-temperature medium is transmitted to the liquid storage tank through the tenth control valve, the pressure of the liquid storage tank is increased, the low-temperature medium in the liquid storage tank flows to the cooler through the main tube through pressure difference, and then the low-temperature medium exchanges heat with the low-temperature medium in the test container, so that the temperature of the low-temperature medium in the test container is reduced.

Preferably, a first pressure gauge for monitoring the pressure of the test container is arranged on the test container;

and a second pressure gauge for monitoring the pressure of the liquid storage tank is arranged on the liquid storage tank.

Preferably, the low-temperature medium is liquid nitrogen, and the heat exchange medium is alcohol.

The implementation of the invention has the following beneficial effects: through the arrangement of the first booster and the second booster, the heat exchange area in the test container and the capacity of heat exchange with the atmosphere are increased and enlarged, the self-evaporation capacity of a low-temperature medium is increased, the boosting speed of the test container is increased, the controllability of the temperature and the pressure of the test container is improved, the inspection time of a safety valve is shortened, the inspection efficiency is improved, and the labor cost is reduced.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

fig. 1 is a schematic structural view of a conventional safety valve inspection device;

fig. 2 is a schematic structural view of a safety valve verifying apparatus of the present invention.

Detailed Description

For a more clear understanding of the technical features, objects and effects of the present invention, embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, it is to be understood that the orientations and positional relationships indicated by "front", "rear", "upper", "lower", "left", "right", "longitudinal", "lateral", "vertical", "horizontal", "top", "bottom", "inner", "outer", "leading", "trailing", and the like are configured and operated in specific orientations based on the orientations and positional relationships shown in the drawings, and are only for convenience of describing the present invention, and do not indicate that the device or element referred to must have a specific orientation, and thus, are not to be construed as limiting the present invention.

It is also noted that, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," "disposed," and the like are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. When an element is referred to as being "on" or "under" another element, it can be "directly" or "indirectly" on the other element or intervening elements may also be present. The terms "first", "second", "third", etc. are only for convenience in describing the present technical solution, and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated, whereby the features defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of such features. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

As shown in fig. 2, the safety valve inspection device of the present invention includes a test container 1 and a liquid storage tank 2, wherein the test container 1 has a horizontal-vertical cylindrical structure having a certain thickness to improve safety performance, and the liquid storage tank 2 has a closed tank structure having a narrow opening or a wide opening, and the opening is closed by a closing cover plate, and a certain volume of low-temperature medium is stored therein, and the volume can be selectively set as required.

The liquid storage tank 2 is communicated with the inner cavity of the test container 1 and can inject low-temperature medium into the test container 1, the top of the test container 1 is provided with a first control valve 51 which is communicated with the inner cavity of the test container 1 and can be connected with a tested safety valve 4, and the top is also provided with an equipment safety valve 3.

Control of the magnitude of the pressure increase rate of the test vessel 1:

in this embodiment, the pressure of the test container 1 is increased mainly by injecting the cryogenic medium into the cryogenic test container 1, and after the cryogenic medium absorbs a certain amount of heat, the cryogenic medium evaporates from a liquid to a gas by self-evaporation, and the volume expands by more than 300 times, so that the pressure in the test container 1 increases.

Because the outer shell of the test container 1 is coated with a certain heat-insulating material, the heat-insulating material influences the heat exchange between the low-temperature medium and the outside, and thus, the self-evaporation of the low-temperature medium is very slow. If the function of the heat-insulating material is reduced (such as the thickness of the heat-insulating layer is reduced), on one hand, the safe use of the container is influenced, and on the other hand, the speed of the pressure rise is difficult to control by reducing the function of the heat-insulating material.

The pressure rise of the test container 1 has a certain relationship with the physical properties of the low-temperature medium, and is illustrated by taking a common low-temperature medium such as liquid nitrogen as an example:

the critical temperature of liquid nitrogen is-146.9 ℃, and the critical pressure is 3.465 MPa.

The physical meaning of the critical temperature of liquid nitrogen is as follows: if the temperature exceeds a certain value, the gas cannot be liquefied any more even if the pressure is increased again, and liquefaction is possible only if the temperature is lower than the value. This particular temperature is referred to as the critical temperature of the gas. Accordingly, the minimum pressure required for a gas to liquefy at a critical temperature is called the critical pressure. The critical pressures of different gases are also different.

That is, to liquefy the nitrogen, it is only possible to lower the temperature of the nitrogen to below the critical temperature of-146.9 ℃. At the critical temperature, liquefaction is only possible when the air is compressed to or above the critical pressure (3.465 MPa). When the pressure of nitrogen is below the critical pressure, the air must be cooled to a temperature below the critical temperature to liquefy it.

Thus, the operating conditions of the test vessel are divided into two cases: one is that the working temperature of the test container 1 is lower than the critical temperature of minus 146.9 ℃; one is that the working temperature of the test container 1 is higher than the critical temperature of minus 146.9 ℃.

When the working temperature of the test container 1 is lower than the critical temperature of minus 146.9 ℃, a gas-liquid two-phase medium exists in the test container 1, so that the possibility and the risk of volume expansion of 300 times and pressure surge when the liquid-phase medium is converted into the gas-phase medium exist. Therefore, at the critical temperature of-146.9 ℃ or lower, the temperature rise rate should be controlled so that the low-temperature liquid is slowly evaporated into a gas, the gas volume is slowly expanded, and the pressure is slowly and controllably raised, and the pressure is slowly raised by controlling the evaporation rate. Meanwhile, in the phase, because phase change (liquid phase is changed into gas phase) exists, the pressure rise amplitude of the test container 1 is large, and the pressure fluctuation range is large.

In order to control the boosting speed and the boosting speed of the test container 1, the subsequent combination of the first booster 6 and the second booster 7 is used for realizing the heat exchange speed of the test container 1, so that the boosting speed is controlled.

Further, in the present embodiment, the test vessel 1 is provided with a first booster 6 in an inner cavity thereof, the first booster 6 includes a first heat exchange pipe 61, the test vessel 1 is provided with a second booster 7 in an outer portion thereof, and the second booster 7 includes a second heat exchange pipe 71.

The first heat exchange tube 61 and the second heat exchange tube 71 are communicated end to form a heat exchange circulation channel for circulation of a heat exchange medium, when the heat exchange medium flows through the first booster 6, the heat exchange medium exchanges heat with the low-temperature medium in the test container 1 to absorb heat, raise the temperature and expand the low-temperature medium, and then the pressure of the test container 1 is raised to verify the tested safety valve 4.

Furthermore, the output end of the second heat exchange pipe 71 is connected to the input end of the first heat exchange pipe 61 through an input pipe 8, the output end of the first heat exchange pipe 61 is connected to the input end of the second heat exchange pipe 71 through an output pipe 9 to form the aforementioned heat exchange circulation channel, the input pipe 8 is provided with a circulation pump 10, a second control valve 52 and a first check valve 111, the circulation pump 10 pumps the heat exchange medium in the second heat exchange pipe 71 into the first heat exchange pipe 61, and the output pipe 9 is provided with a third control valve 53.

In this embodiment, the first heat exchanging tube 61 and the second heat exchanging tube 71 are substantially labyrinth-shaped or racetrack-shaped bent structures, and are bent in multiple sections to form a multi-row tube bundle shape, so as to increase the heat exchanging area, generally as shown in fig. 2, the first heat exchanging tube 61 is a multi-row tube bundle arranged in the up-down direction, certain tube rows are arranged in the horizontal direction (the specific number depends on the requirement of the actual pressure increasing speed), and the length in the horizontal direction can be set according to the requirement, which is not specifically limited herein.

It can be understood that the position arrangement of the above components can be adjusted according to actual requirements, for example, a circulation pump 10, a second control valve 52 and a first check valve 111 can be sequentially arranged from the second heat exchange pipe 71 to the first heat exchange pipe 61, the circulation pump 10 is used for pumping the heat exchange medium from the second heat exchange pipe 71 into the first heat exchange pipe 61, and the heat exchange medium completing the heat exchange in the first heat exchange pipe 61 can also be pumped back into the second heat exchange pipe 71 through the output pipeline 9 and the third control valve 53 to complete the circulation. The second control valve 52 and the third control valve 53 may be provided in plural, and are not particularly limited herein.

Further, the second booster 7 further includes one or more fans 72, and an air outlet of the fan 72 is disposed toward the second heat exchange pipe 71. In the embodiment, the second heat exchange tubes 71 are a multi-row tube bundle arranged along the vertical direction, and the fan 72 can be a plurality of tubes arranged along the length extension direction of the second heat exchange tubes 71 to improve the heat exchange efficiency.

The heat exchange medium is liquid with a freezing point of-117.3 ℃, in the embodiment, the heat exchange medium is alcohol, and the reason for selecting the alcohol is as follows: alcohol is liquid, and has better heat conductivity coefficient than gas, so liquid is preferably selected; the freezing point of alcohol is-117.3 deg.C, and the boiling point is 78.5 deg.C. In this way, the state of the medium in the booster pipe can be kept in a liquid state throughout the operation. For the same reason, other liquids similar to alcohol can also be used as the heat exchange medium.

In this embodiment, the circulation pump 10 is started, and the heat exchange medium (e.g., alcohol) flows into the first booster 3 through the second control valve 52 and the first check valve 111, and immediately after the start, the heat exchange medium is at a normal temperature. Therefore, a certain temperature difference exists between the heat exchange medium at the normal temperature and the low-temperature liquid nitrogen, so that the heat exchange between the heat exchange medium and the low-temperature liquid nitrogen can be realized, and the heat is transferred to the low-temperature liquid nitrogen in the test container 1 through the pipe wall by the heat exchange medium. After heat exchange occurs, the cryogenic liquid nitrogen will self-evaporate, the cryogenic medium will expand in volume, and the pressure of the test vessel 1 will rise.

After the heat exchange of the first booster 6 is completed, the heat exchange medium flows to the second booster 7 through the third control valve 53, and in order to realize efficient heat exchange, the fan 72 is started to realize that the heat exchange medium cooled in the second booster 7 pipe performs heat exchange with the heat of the atmospheric environment through the pipe wall, so that the heat exchange medium in the pipe is heated again.

After the temperature rise, the mixture is pressurized again by the circulation pump 10, flows into the first booster 6 in the test vessel 1, and passes through: the heat transfer medium absorbs heat in the test container 1, the low-temperature liquid nitrogen evaporates, the heat transfer medium absorbs heat of the atmospheric environment, the heat transfer medium is heated, the heat transfer medium is input into the first booster 6 again, the low-temperature liquid nitrogen evaporates in a repeated mode, and the working parameters in the test container 1 reach certain pressure and temperature.

When the working temperature of the test container 1 is higher than the critical temperature to be more than minus 146.9 ℃, at this time, as the working temperature of the test container 1 exceeds the critical temperature, the low-temperature medium in the test container 1 presents a single gas phase, the increase of the pressure in the test container 1 is related to the temperature, and the specific relation is considered according to an ideal gas isochoric equation, namely: P1T 1P 2T 2, i.e. the pressure increases proportionally with the temperature. However, the range of the rise pressure at this stage is small.

The pressure increase of the test vessel 1 at this stage is a proportional increase in the temperature. The operation principle is the same as the above, and the heat exchange of the first booster 6 is also realized.

Control of the temperature decrease of the cryogenic medium:

as can be seen from the foregoing, the pressure of the cryogenic medium in the test container 1 is increased by heat exchange with the outside, by self-evaporation or by an increase in the temperature of the medium. Thus, the test procedure is primarily a temperature increase, and, in general, the higher the temperature, the higher the pressure. Under the inspection condition of some safety valves, the medium temperature is required to be lower, and meanwhile, the pressure is also higher; even requiring that the temperature of the medium be reduced.

The temperature decrease is divided into two cases: the temperature reduction range of the low-temperature medium is large and the temperature reduction range of the low-temperature medium is small.

1) Large reduction range of medium temperature

In this embodiment, a method of directly injecting low-temperature liquid nitrogen during the pressure increasing and temperature decreasing processes is adopted. The low temperature liquid nitrogen evaporates in the test container 1, and due to the low ambient temperature, the ambient temperature is further reduced after evaporation by absorbing ambient heat, and this reduction is large.

Specifically, in the present embodiment, the liquid storage tank 2 is communicated with the inner cavity of the test container 1 through the injection line 12, and the fourth control valve 54, the second check valve 112, and the fifth control valve 55 are sequentially disposed on the injection line 12 from the liquid storage tank 2 to the test container 1, so as to control the flow rate and the flow rate of the low-temperature medium in the liquid storage tank 2 injected into the test container 1. It can be understood that the injection line 12 extends below the level of the cryogenic medium in the reservoir 2, and the number of components arranged thereon can be increased or decreased according to the actual requirements, and only a preferred technical solution is given here.

The top of the test container 1 is provided with a first thermometer 131, and the bottom thereof is provided with a second thermometer 132 for detecting the temperature difference between the upper and lower ends of the test container 1. The test container 1 is provided with a first pressure gauge 191 for monitoring the pressure of the test container 1 and a second pressure gauge 192 arranged in the liquid storage tank 2 for monitoring the pressure of the liquid storage tank 2. Two thermometers are respectively arranged at the top and the bottom of the test container 1, and whether a gas-liquid two-phase medium exists or not is judged according to the temperature difference. The liquid phase temperature is low and the gas phase temperature is relatively high.

The bottom of the test container 1 is provided with a return pipe 14, and the return pipe 14 is provided with a third check valve 113 and a sixth control valve 56. The return line 14 can be connected to the fourth control valve 54 to the filling line 12 of the tank 2 to achieve doubling and wire reduction.

When the temperature difference is the first preset temperature difference, the sixth control valve 56 is opened, and the redundant low-temperature medium in the test container 1 flows back to the liquid storage tank 2 by using the pressure difference between the test container 1 and the liquid storage tank 2.

It can be understood that, after a certain temperature is reached, the temperature between the first thermometer 131 and the second thermometer 132 is compared, and if a certain temperature difference exists, and the temperature difference reaches a first preset temperature difference (which is set according to actual requirements), it indicates that the second thermometer 132 detects that the low-temperature liquid nitrogen is not evaporated, so that there is a possibility that the low-temperature liquid nitrogen continues to evaporate and the temperature further decreases, and for this reason, the redundant low-temperature liquid nitrogen is returned to the low-temperature liquid storage tank 2 again by using the pressure difference between the test container 1 and the liquid storage tank 2 through the return pipe 14, the third check valve 113 and the sixth control valve 56 until the temperature difference between the thermometers 1 and 2 is controlled within a certain range, such as a second preset temperature difference (which can be set according to actual requirements).

2) The temperature reduction range of the low-temperature medium is small:

in the present embodiment, a cooler 15 communicating with the reservoir tank 2 is provided inside the test container 1, and a third booster 16 having both ends connected to the reservoir tank 2 and the cooler 15 is provided outside the test container 1.

The desuperheater 15 comprises a third heat exchange pipe 151, the input end of the third heat exchange pipe 151 is connected into the injection pipeline 12 between the second check valve 112 and the fifth control valve 55 through a seventh control valve 57, the output end of the third heat exchange pipe 151 is communicated with the liquid storage tank 2 through a main pipe 17, and an eighth control valve 58, a ninth control valve 59 and a tenth control valve 510 are sequentially arranged on the main pipe 17 from the third heat exchange pipe 151 to the liquid storage tank 2. The main pipe 17 extends into the liquid storage tank 2 and is positioned above the liquid level of the low-temperature medium.

The safety valve inspection device further includes a bypass pipe 18 connected in parallel to both ends of the ninth control valve 59, the third booster 16 is provided on the bypass pipe 18, the third booster 16 includes a fourth heat exchange pipe 161, an input end of the fourth heat exchange pipe 161 is connected to the main pipe 17 between the eighth control valve 58 and the ninth control valve 59 through an eleventh control valve 511, and an output end of the fourth heat exchange pipe 161 is connected to the main pipe 17 between the ninth control valve 59 and the tenth control valve 510 through a twelfth control valve 512.

In this embodiment, the third heat exchanging tube 151 and the fourth heat exchanging tube 161 are bent to form a labyrinth-shaped or raceway-shaped bent structure, and are bent in multiple sections to form a multi-row tube bundle shape, so as to increase the heat exchanging area, generally as shown in fig. 2, the third heat exchanging tube 151 is a multi-row tube bundle arranged in the vertical direction, certain tube rows are arranged in the horizontal direction (the specific number depends on the actual pressure increasing speed), and the length in the horizontal direction can be set according to the requirement, which is not specifically limited herein. The third heat exchange pipe 151 is disposed at an upper portion of the inner space of the test vessel 1.

In this embodiment, the heat exchange tube of booster and the heat exchange tube of desuperheater all can adopt the general fluorescent tube of heat transfer effect, also can adopt the better fin tube of heat transfer effect, or other tubular products, do not specifically limit here. The second booster 7 and the third booster 16 may be in the form of heat exchange with the atmosphere, such as a fan, or may be in the form of sprinkling with liquid as a heat exchange medium (such as water), such as a sprinkling device that sprinkles against the second heat exchange pipe 71 and the fourth heat exchange pipe 161.

The ninth control valve 59 is closed, the eleventh control valve 511 and the twelfth control valve 512 are opened, at this time, the low-temperature medium in the fourth heat exchange tube 161 exchanges heat with the external atmosphere environment, the temperature rises, the pressure in the fourth heat exchange tube 161 rises, the low-temperature medium is transmitted to the liquid storage tank 2 through the tenth control valve 510, the pressure of the liquid storage tank 2 rises, the low-temperature medium in the liquid storage tank 2 flows to the cooler 15 through the main tube 17 through the pressure difference, so as to exchange heat with the low-temperature medium in the test container 1, and the temperature of the low-temperature medium in the test container 1 is reduced.

It can be understood that if the temperature of the test container 1 is reduced in a small range, the ninth control valve 59 may be closed, and the twelfth control valve 512 and the eleventh control valve 511 may be opened, at this time, the low-temperature medium in the four heat exchange tubes 161 exchanges heat with the external atmosphere, the temperature is increased, the pressure in the tubes is increased, and then the low-temperature medium is transmitted to the liquid storage tank 2 through the tenth control valve 510, the pressure in the liquid storage tank 2 is increased, and the low-temperature liquid nitrogen in the liquid storage tank 2 is pumped out through the pressure difference, and flows through the fourth control valve, the second check valve 112, the seventh control valve 57 and the temperature reducer 15. Due to the second check valve 112, the fluid flow is only from the reservoir 2 to the test container 1 and not in the reverse direction.

After the pressure rise and the injection of the low-temperature liquid nitrogen into the test container 1 are completed, the twelfth control valve 512 and the eleventh control valve 511 are closed, the ninth control valve 59 is opened, the low-temperature medium in the cooler 15 and the low-temperature medium in the test container 1 are subjected to heat exchange, the low-temperature medium in the cooler 15 is slowly raised, the low-temperature medium in the test container 1 is reduced in a small amplitude, and the temperature of the medium is reduced in a small amplitude.

The heat exchange balance and the temperature balance are achieved, the pressure tends to be stable, and the low-temperature medium in the cooler 15 tube tends to be stable and does not flow any more. The seventh control valve 57 and the eighth control valve 58 can be closed to keep the temperature relatively stable.

In this embodiment, the verification of the low-temperature safety valve is implemented as follows:

firstly, all valves and related equipment are confirmed to be in a closed state, and meanwhile, the tested safety valve 4 is installed.

And (3) opening the fourth control valve 54 and the fifth control valve 55, wherein the pressure of the liquid storage tank 2 is normal working pressure, the test container 1 is normal pressure (atmospheric pressure environment), and the low-temperature medium (low-temperature liquid nitrogen) flows from the liquid storage tank 2 to the low-temperature test container 1 through the fourth control valve 54, the second check valve 112 and the fifth control valve 55 and starts self-evaporation.

In order to accelerate the evaporation speed, the second control valve 52 and the third control valve 53 are opened, the circulating pump 10 is started, the fan 72 is started, so that the heat exchange medium (such as alcohol) in the second heat exchange pipe 71 flows into the first booster 3 through the circulating pump 10, the second control valve 52 and the first check valve 111, the heat exchange medium (such as alcohol) in the first heat exchange pipe 61 exchanges heat with the low-temperature medium outside the pipe through the pipe wall, the low-temperature liquid nitrogen in the test container 1 is self-evaporated, and the pressure in the test container 1 is increased.

During the pressure increasing process, the safety valve 4 to be tested can be opened manually intermittently by opening the first control valve 51 so as to lower the temperature of the safety valve 4 to be tested (the test requires that the safety valve 4 to be tested also lower the temperature). The temperature is lowered by the time and frequency of the intermittent opening of the safety valve 4 to be tested. Meanwhile, a certain amount of gas is discharged through the safety valve 4 to be tested, so that the requirements of normal working pressure and no overpressure of the test container 1 are met.

After the heat exchange of the first booster 6 is completed, the heat exchange medium flows to the second booster 7 through the third control valve 53, in order to realize efficient heat exchange, the fan 72 is started, and under the acceleration of the fan 72, the heat exchange medium cooled in the second booster 7 pipe is subjected to heat exchange with the heat of the atmospheric environment through the pipe wall, so that the heat exchange medium in the pipe is heated again, and the heat exchange medium is injected into the first booster 6 again through the circulating pump. The circulation realizes the heat exchange and the temperature rise of the low-temperature medium in the test container 1.

In the process of boosting, the pressure is found to meet the requirement, but the temperature of the medium is higher, so that the test requirement is not met, and the temperature needs to be reduced. The method comprises the following steps:

1) the temperature needs to be reduced below the critical temperature of liquid nitrogen of minus 146.9 DEG C

Because the critical temperature of the liquid nitrogen is-146.9 ℃, the temperature of the medium in the test container 1 needs to be reduced to be below-146.9 ℃, a large amount of liquid nitrogen exists in the test container 1, and the gas phase and the liquid phase of the liquid nitrogen coexist. By increasing the circulation of the heat exchange medium in the first booster 6, the low-temperature liquid nitrogen is quickly evaporated, and the temperature is quickly reduced. The magnitude of the decrease is seen how much liquid phase liquid nitrogen evaporates. The test procedure took care to observe the temperature difference between the first thermometer 131 and the second thermometer 132 (the first thermometer 131 showed a temperature greater than the second thermometer 132 showed a temperature) indicating the presence of liquid phase cryogenic liquid nitrogen.

2) The temperature needs to be reduced to be higher than the critical temperature of liquid nitrogen to minus 146.9 DEG C

The temperature of the medium in the test container 1 needs to be reduced to be higher than minus 146.9 ℃, and people worry that the safe operation of the container is influenced because the working temperature of the medium of the container is higher than the critical temperature of liquid nitrogen to minus 146.9 ℃ and the pressure of the container is raised probably because the liquid nitrogen is completely evaporated.

Therefore, when the temperature of the container medium falls to any one of the temperatures specified in the test, the temperature difference between the first thermometer 131 and the second thermometer 132 is observed (the temperature indicated by the first thermometer 131 is higher than the temperature indicated by the second thermometer 132), and the temperature difference indicates the presence of liquid-phase low-temperature liquid nitrogen. At this time, the pressures of the first pressure gauge 191 and the second pressure gauge 192 are observed at the same time; if the display pressure of the first pressure gauge 19 is greater than 1 and the display pressure of the second pressure gauge 192 is greater than 1, the sixth control valve 56 is opened, and redundant low-temperature liquid nitrogen flows to the liquid storage tank 2 from the test container 1 under the action of the pressure; if the display pressure of the first pressure gauge 191 is lower than that of the second pressure gauge 192, the heat exchange of the third booster 16 is increased, so that the low-temperature liquid nitrogen is evaporated, the pressure is increased until the display pressure of the second pressure gauge 192 is higher than that of the first pressure gauge 191, and thus, the sixth control valve 56 is opened, and redundant low-temperature liquid nitrogen flows to the liquid storage tank 2 from the test container 1 under the action of the pressure.

When the pressure and the temperature of the test container 1 reach preset parameters, the pressure is slowly increased continuously through the first booster 6 and the second booster 7 until the pressure in the test container 1 reaches preset setting pressure of the tested safety valve 4, the tested safety valve 4 is opened, and the checking of the setting pressure is completed.

The tested safety valve 4 is opened, certain media are discharged, the pressure in the test container 1 is reduced, and the tested safety valve 4 returns to a seat. The pressure of the low-temperature medium in the test container 1 is increased again through the first booster 6 and the second booster 7 until 90% of the set pressure is reached, and whether leakage exists is judged through observation and instrument detection. And if the detection condition meets the requirement and the sealing test is qualified, considering that 90% of the set pressure is the sealing pressure.

Thus, the calibration of the setting pressure and the sealing pressure is completed. And closing the related control valve, and finishing the test.

According to the invention, through the arrangement of the first booster 6 and the second booster 7, the self-evaporation capacity of the low-temperature medium is increased by increasing and enlarging the heat exchange area in the test container 1 and the capacity of heat exchange with the atmosphere, so that the boosting speed is increased, the controllability of the temperature and the pressure of the test container 1 is improved, the inspection time of the safety valve is shortened, the inspection efficiency is improved, and the labor cost is reduced. Meanwhile, when the temperature of the test container 1 is higher than the critical temperature of-146.9 ℃, rapid temperature reduction and pressure increase can be realized through evaporation.

Also, the temperature reducer 15 is provided to reduce the temperature of the test container 1 accurately in a small range. By combining active and passive technologies, the inspection time of the safety valve is shortened, and the controllability of the temperature and the pressure of the test container 1 is improved.

It is to be understood that the foregoing examples, while indicating the preferred embodiments of the invention, are given by way of illustration and description, and are not to be construed as limiting the scope of the invention; it should be noted that, for those skilled in the art, the above technical features can be freely combined, and several changes and modifications can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention; therefore, all equivalent changes and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims

1. A safety valve inspection device comprises a test container (1) and a liquid storage tank (2), wherein the liquid storage tank (2) is communicated with the inner cavity of the test container (1) and can be used for injecting a low-temperature medium into the test container (1); the top of the test container (1) is provided with a first control valve (51) which is communicated with the inner cavity of the test container (1) and can be connected with a tested safety valve (4), and the test device is characterized in that,

a first booster (6) is arranged in the inner cavity of the test container (1), and the first booster (6) comprises a first heat exchange pipe (61); a second booster (7) is arranged outside the test container (1), and the second booster (7) comprises a second heat exchange pipe (71);

the first heat exchange tube (61) is communicated with the second heat exchange tube (71) end to form a heat exchange circulation channel for a heat exchange medium to flow through, when the heat exchange medium flows through the first booster (6), the heat exchange medium exchanges heat with a low-temperature medium in the test container (1) to absorb heat, raise the temperature and expand the low-temperature medium, and then the pressure of the test container (1) is raised to verify the tested safety valve (4).

2. The safety valve testing device according to claim 1, wherein the output end of the second heat exchanging pipe (71) is connected to the input end of the first heat exchanging pipe (61) through an input line (8), and the output end of the first heat exchanging pipe (61) is connected to the input end of the second heat exchanging pipe (71) through an output line (9) to form the heat exchanging circulation passage;

a circulating pump (10), a second control valve (52) and a first check valve (111) are arranged on the input pipeline (8), and a heat exchange medium in the second heat exchange pipe (71) is pumped into the first heat exchange pipe (61) by the circulating pump (10);

and a third control valve (53) is arranged on the output pipeline (9).

3. The safety valve checking device according to claim 2, characterized in that the second booster (7) further comprises one or more fans (72);

the air outlet of the fan (72) faces the second heat exchange pipe (71).

4. The safety valve testing device according to any one of claims 1 to 3, wherein the liquid storage tank (2) is communicated with the inner cavity of the test container (1) through an injection line (12), and a fourth control valve (54), a second check valve (112) and a fifth control valve (55) are sequentially arranged on the injection line (12) from the liquid storage tank (2) to the test container (1) so as to control the flow rate and the flow rate of the low-temperature medium in the liquid storage tank (2) injected into the test container (1).

5. The safety valve inspection device according to claim 4, wherein a first thermometer (131) is provided at the top of the test container (1), and a second thermometer (132) is provided at the bottom thereof, for detecting a temperature difference between the upper and lower ends of the test container (1);

a return pipe (14) is arranged at the bottom of the test container (1), and a third check valve (113) and a sixth control valve (56) are arranged on the return pipe (14);

when the temperature difference is a first preset temperature difference, the sixth control valve (56) is opened, and redundant low-temperature media in the test container (1) are returned to the liquid storage tank (2) by utilizing the pressure difference between the test container (1) and the liquid storage tank (2).

6. The safety valve testing device according to claim 5, characterized in that a temperature reducer (15) communicated with the liquid storage tank (2) is arranged inside the test container (1);

and a third booster (16) is arranged outside the test container (1), and two ends of the third booster are respectively connected with the liquid storage tank (2) and the cooler (15).

7. The safety valve testing device according to claim 6, characterized in that the desuperheater (15) comprises a third heat exchange pipe (151), the input end of the third heat exchange pipe (151) being connected to the injection line (12) between the second check valve (112) and the fifth control valve (55) through a seventh control valve (57);

the output end of the third heat exchange tube (151) is communicated with the liquid storage tank (2) through a main tube (17), and an eighth control valve (58), a ninth control valve (59) and a tenth control valve (510) are sequentially arranged on the main tube (17) of the liquid storage tank (2) from the third heat exchange tube (151).

8. The safety valve inspection device as set forth in claim 7, further comprising a bypass pipe (18) connected in parallel to both ends of the ninth control valve (59);

the third booster (16) is arranged on the bypass pipe (18), the third booster (16) comprises a fourth heat exchange pipe (161), and the input end of the fourth heat exchange pipe (161) is connected to the main pipe (17) between the eighth control valve (58) and the ninth control valve (59) through an eleventh control valve (511);

the output end of the fourth heat exchange pipe (161) is connected to the main pipe (17) between the ninth control valve (59) and the tenth control valve (510) through a twelfth control valve (512);

the ninth control valve (59) is closed, the eleventh control valve (511) and the twelfth control valve (512) are opened, at this time, the low-temperature medium in the fourth heat exchange tube (161) exchanges heat with the external atmosphere environment, the temperature is increased, the pressure in the tube of the fourth heat exchange tube (161) is increased, the low-temperature medium is transmitted into the liquid storage tank (2) through the tenth control valve (510), the pressure of the liquid storage tank (2) is increased, and the low-temperature medium in the liquid storage tank (2) flows to the cooler (15) through the main tube (17) by pressure difference to exchange heat with the low-temperature medium in the test container (1) so as to reduce the temperature of the low-temperature medium in the test container (1).

9. The safety valve testing device according to claim 8, characterized in that a first pressure gauge (191) is provided on the test container (1) for monitoring the pressure of the test container (1);

and a second pressure gauge (192) for monitoring the pressure of the liquid storage tank (2) is arranged on the liquid storage tank (2).

10. The safety valve testing device of claim 9, wherein the cryogenic medium is liquid nitrogen and the heat exchange medium is alcohol.