Three-way valve for realizing in-situ calibration of pressure gauge

Abstract

The utility model relates to a three-way valve for realizing in-situ calibration of a pressure gauge, which comprises a valve body, a piston matched with the inner wall of the valve body, a gas storage tank interface, a monitoring pressure gauge interface and a pressure calibration system interface, the gas storage tank interface and the pressure calibration system interface are positioned at two ends of the valve body, and the monitoring pressure gauge interface is positioned on the side surface of the valve body. A through hole of the monitoring pressure gauge interface is filled with a copper silencing material; the piston is provided with two cavities, the side, close to the gas storage tank connector, of the piston is a pressure monitoring cavity, the side, close to the pressure calibration system connector, of the piston is a pressure calibration cavity, and the two cavities are each provided with a vent hole leading to the valve body. Correspondingly, the piston is divided into a pressure monitoring side and a pressure calibration side; an annular sealing groove and an O-shaped sealing ring matched with the annular sealing groove are arranged on the outer wall of the joint of the two cavities. The utility model also provides a pressure gauge in-situ calibration method realized by using the three-way valve.

Description

Technical Field

[0001] The utility model relates to a three-way valve for realizing in-situ calibration of a pressure gauge, which can be used for monitoring the pressure of a gas storage tank and in-situ calibration of a monitoring pressure gauge in a gas supply or pneumatic system, or for monitoring the pressure of a pipeline with a working pressure not greater than 2 MPa and in-situ calibration of a monitoring pressure gauge in a gas supply or pneumatic system. Background Technique

[0002] Gas storage tanks are commonly used in gas production, storage and supply, and sometimes are used as air capacitances in pneumatic systems. They are common pressure vessels in industrial production and are an indispensable and important component in hospital medical gas engineering and plateau gas production and supply systems. Monitoring the pressure of a gas storage tank is generally achieved by connecting a monitoring pressure gauge to the gas storage tank through a straight-through joint or a straight-through stop valve. Such joints or stop valves play a very important role in the safe use of gas storage tanks. However, in actual use, the existing installation methods often have the following defects:

[0003] 1. The monitoring pressure gauge connected to the gas storage tank through a straight-through joint cannot be removed for calibration or verification when the system is in a working state;

[0004] 2. Although the monitoring pressure gauge connected to the gas storage tank through a straight-through stop valve can be removed during the working state, there may be a situation where the stop valve is wrongly closed, and there is a safety risk of the monitoring function of the pressure gauge failing.

[0005] As a real-time and long-term air pressure monitoring device, the system monitoring pressure gauge or other monitoring pressure instruments or sensors (hereinafter referred to as "monitoring pressure gauge") and the monitored part (gas storage tank or system pipeline) should always be connected, and correctly reflect the pressure at the monitoring point. Therefore, the periodic verification or calibration of the pressure gauge is very necessary. At present, the connection structure between monitoring points such as gas storage tanks and monitoring pressure gauges cannot directly access external calibration equipment. Usually, maintenance or inspection personnel of gas supply or pneumatic systems must first remove the monitoring pressure gauge from the monitoring point, install a pressure gauge of the same specification that has passed metrological verification instead of the original one, and then send the removed original pressure gauge to a metrological verification institution for verification. This non-in-situ operation mode has various disadvantages:

[0006] 1. The gas storage tank is a pressure vessel, and its working pressure is much higher than the atmospheric pressure. During the disassembly operation of the pressure gauge, there is a possibility that the pressure gauge or other joint-related workpieces may accidentally pop out due to improper operation. Moreover, some pressure gauges are installed at a relatively high position, and the long disassembly time also increases the risk of accidental falling of personnel;

[0007] 2. The disassembly and transportation of the pressure gauge may damage the pressure gauge itself and the system interface, reduce the service life of the pressure gauge, and there are potential hazards affecting the airtightness and safety of the system;

[0008] 3. At present, the practice of "one in use and one in reserve" for the pressure gauges that are calibrated / verified off-site will increase the difficulty of metrological management of the gas system monitoring equipment;

[0009] 4. At present, there are cases in the literature showing that in-situ calibration can be achieved by modifying the pressure monitoring point and installing a structure with two manual stop valves. This method has many operation steps during in-situ calibration (the stop valves need to be opened and closed multiple times), and there is a possibility that the operator forgets to open the stop valve after calibration, resulting in the disconnection between the monitoring pressure gauge and the gas storage tank, losing its safety monitoring function and posing a greater safety hazard.

[0010] In summary, there are still many inconveniences and even potential hazards in the existing connection structure between the gas storage tank and the monitoring pressure gauge. Therefore, it is of great significance and practical value to study a three-way valve that is safe, convenient, and can realize pressure monitoring and in-situ calibration of the pressure gauge. Summary of the Invention

[0011] The purpose of this utility model patent is to provide a three-way valve for the safety monitoring of the gas storage tank or pipeline in the gas supply or pneumatic system, which can be used for pressure monitoring and at the same time can realize the in-situ calibration of the monitoring pressure gauge. This valve has a structural design to prevent incorrect operation, so as to solve the problems raised in the above background technology. The technical solution is as follows:

[0012] A three-way valve for realizing in-situ calibration of a pressure gauge, including a valve body 1, a piston 2 that fits with the inner wall of the valve body 1, a gas storage tank interface 3, a monitoring pressure gauge interface 6, and a pressure calibration system interface 7. The gas storage tank interface 3 and the pressure calibration system interface 7 are located at both ends of the valve body, and the monitoring pressure gauge interface 6 is located on the side of the valve body. It is characterized in that,

[0013] The through hole of the monitoring pressure gauge interface 6 is filled with copper sound-absorbing material 8; the piston 2 is provided with two cavities. The side close to the gas storage tank interface 3 is a pressure monitoring cavity 12, and the side close to the pressure calibration system interface 7 is a pressure calibration cavity 13. The two cavities are respectively provided with ventilation holes leading to the valve body; correspondingly, the piston is divided into two parts: a pressure monitoring side and a pressure calibration side; a ring-shaped sealing groove and a matching O-ring 9 are provided on the outer wall at the junction of the two cavities; the three-way valve includes two working positions. One is the daily detection position. At this time, the piston is far from the gas storage tank interface 3, and the ventilation hole of the pressure monitoring cavity 12 leads to the monitoring pressure gauge interface. The other is the in-situ calibration position. At this time, the piston is close to the gas storage tank interface 3, and the ventilation hole of the pressure calibration cavity 13 leads to the pressure gauge interface.

[0014] Furthermore, the two cavities are respectively provided with pressure relief holes leading to the valve body.

[0015] Furthermore, a filter disc 11 is provided at the end of the pressure calibration cavity 13 of the piston.

[0016] Further, the filter sheet 11 is made of copper sound-absorbing material.

[0017] Further, a color ring 14 is designed at the outer wall end of the pressure calibration side of the piston. When the three-way valve is in the daily detection position, it is in an exposed state to indicate whether the three-way valve is in the daily detection position.

[0018] The utility model can realize the in-situ detection and calibration of the pressure gauge, and can effectively avoid various defects and potential hazards brought by the non-in-situ operation of traditional air pipe joints. The three-way valve of the utility model utilizes the thrust generated by the pressure difference between the pressure of the monitoring point such as the gas supply or the air storage tank of the pneumatic system and the ambient atmospheric pressure to replace the solution that the valve body design in the daily detection position most likely adopts a spring structure. This not only simplifies the structural design but also increases the reliability of the three-way valve. In addition, the utility model can provide a visual prompt for the connection situation in the daily pressure monitoring state, enabling the user or maintainer of the gas supply or pneumatic system to confirm whether the monitoring point such as the air storage tank and the monitoring pressure gauge are in a connected state by checking whether the color ring is exposed. The three-way valve of the utility model is simple and convenient to operate, occupies a small space, and can provide more favorable technical conditions for the pressure monitoring of the air storage tank and the in-situ calibration of the monitoring pressure gauge. Description of the Drawings

[0019] Figure 1 Schematic diagram of the working state of the three-way valve for pressure monitoring (daily detection position)

[0020] Figure 2 Schematic diagram of the working state of the three-way valve for pressure calibration (in-situ calibration position)

[0021] The description of the reference numerals is as follows

[0022] 1 Valve body 2 Piston 3 Air storage tank interface 4 Third O-ring

[0023] 5 Stud (mounting screw) 6 Monitoring pressure gauge interface 7 Pressure calibration system interface 8 Copper sound-absorbing material

[0024] 9 Second O-ring 10 Fourth seal 11 Filter sheet 12 Pressure monitoring chamber

[0025] 13 Pressure calibration chamber 14 Color ring 15 Piston limiting platform 16 Pressure monitoring chamber vent hole

[0026] 17 Pressure calibration chamber vent hole 18 First O-ring 19 Pressure monitoring chamber pressure relief hole 20 Pressure calibration chamber pressure relief hole 21 Pressure calibration system quick connector (example, not a component of the utility model) Detailed Embodiment

[0027] The following describes the utility model in conjunction with the drawings and embodiments.

[0028] As Figure 1 AndFigure 2 As shown, the three-way valve for realizing in-situ calibration of a pressure gauge of the utility model comprises a valve body 1, a piston 2 matched with the inner wall of the valve body 1, a gas storage tank interface 3, a monitoring pressure gauge interface 6 and a pressure calibration system interface 7. The gas storage tank interface 3 and the pressure calibration system interface 7 are located at both ends of the valve body, and the monitoring pressure gauge interface 6 is located on the side of the valve body.

[0029] After the piston 2 is installed into the valve body 1, the gas tank interface 3 is sealed and connected to the valve body 1 through the fourth O-ring 10 and the stud 5. The assembled three-way valve is connected to the gas tank through the gas tank interface 3, connected to the monitoring pressure gauge through the monitoring pressure gauge interface 6 of the valve body, and connected to the pressure calibration system with the pressure standard as the main body through the external thread of the valve body pressure calibration system interface 7. The through hole of the valve body monitoring pressure gauge interface 6 is filled with a breathable copper silencing material 8 of a certain strength, which is mainly used to prevent the second O-ring 9 from being crushed when passing through the through hole back and forth, so as to avoid damage or detachment of the sealing ring. A filter 11 is installed on the side of the piston close to the pressure calibration system interface 7. The filter 11 is composed of a copper silencing material of a certain thickness to prevent dust and other impurities from entering the gas supply or pneumatic system.

[0030] There are two cavities in the piston 2, the left side is the pressure monitoring cavity 12, and the right side is the pressure calibration cavity 13; the pressure calibration system interface of the piston is designed with a colored ring 14, which is in an exposed state when the three-way valve is in the daily detection position, and is used to indicate whether the three-way valve is in the daily detection position.

[0031] The three-way valve has two main positions, one is the daily inspection position (such as Figure 1 ) as shown, and the second is the in-situ calibration position (such as Figure 2 As shown). When the three-way valve is in the "daily inspection position", the working pressure (gauge pressure, usually in the range of 0.3MPa to 2MPa) in the gas tank causes the piston to press against the side of the pressure calibration system interface 7, and is limited by the piston limiter 15. The monitoring pressure gauge side is connected to the gas tank through the vent 16 of the pressure monitoring chamber. At the same time, under the joint action of the piston and the second O-ring 9, the pressure calibration system side is cut off from the monitoring pressure gauge and the gas tank. At this time, the monitoring pressure gauge normally monitors the gas tank pressure. When the three-way valve is in the "in-situ calibration position", the monitoring pressure gauge interface side is connected to the pressure calibration system interface through the vent 17 of the pressure calibration chamber, and under the joint action of the piston and the second O-ring 9, the monitoring pressure gauge interface side is cut off from the gas tank interface side. At this time, the monitoring pressure gauge can be calibrated by operating the pressure calibration system.

[0032] Generally, the pipe diameters of gas supply or pneumatic system pipes are used according to standardized and serialized specifications. The pipe diameters are usually 6, 8, 10, 12, 14, 18, 22, 28, and 33 mm. The axial outer diameter of the three-way valve needs to match the pipes used at the monitoring points, and the specific dimensions need to meet the requirements of standardized and serialized specifications. The inner diameter of the three-way valve can be relatively free from the serialized limit conditions through structural design. The thrust range of the piston can be determined by the size of the inner diameter. The thrust formula is For example, when the inner diameter of the three-way valve is designed to be 8 mm, when the working pressure (gauge pressure) of the system air storage tank or pipeline is in the range of 0.3 MPa to 2.0 MPa, the thrust range is 15.072 N to 100.48 N. This not only ensures sufficient stability when the three-way valve is working in the "daily calibration position", but also ensures that the pressure calibration system quick connector 21 can be manually screwed onto the pressure calibration system interface 7 of the three-way valve, so that the three-way valve can safely enter the "in-situ calibration position".

[0033] During the process of the three-way valve switching from the "daily detection position" to the "in-situ calibration position", when the second O-ring 9 passes through one side of the monitoring pressure gauge through-hole (the right side of the through-hole in the figure), due to the tolerance between the valve body and the piston, the relatively high working pressure in the monitoring pressure gauge is slowly released to the pressure calibration system side (at this time, the pressure calibration system side is the ambient atmospheric pressure) through the gap between the valve body and the piston. When the pressure calibration chamber relief hole 20 reaches one side of the monitoring pressure gauge through-hole (the right side of the through-hole in the figure), the possible pressure difference of the monitoring pressure gauge is released to the pressure calibration system interface side through the pressure calibration chamber relief hole 20 to achieve pressure balance between the two. When the second O-ring 9 reaches the other side of the monitoring pressure gauge through-hole (the left side of the through-hole in the figure), the monitoring pressure gauge is cut off from the air storage tank side, and the three-way valve enters the "in-situ calibration position".

[0034] After the in-situ calibration of the pressure is completed, operate the standard pressure gauge on the pressure calibration system side to make the entire system in the atmospheric pressure state (this step is a specified action in the high-pressure pressure calibration procedure). When unscrewing the quick connector 21 of the pressure calibration system to switch the three-way valve from the "in-situ calibration position" to the "daily detection position", when the second O-ring 9 passes through one side of the through-hole of the monitoring pressure gauge (the left side of the through-hole in the figure), due to the tolerance between the valve body and the piston, the relatively high working pressure in the gas storage tank is slowly released to the monitoring pressure gauge side through the pressure monitoring chamber pressure relief hole 19, the pressure monitoring chamber vent hole, and the gap between the valve body and the piston (at this time, the monitoring pressure gauge side is the ambient atmospheric pressure). When the pressure calibration chamber pressure relief hole 19 reaches one side of the through-hole of the monitoring pressure gauge (the left side of the through-hole in the figure), the possible pressure difference between the gas storage tank and the monitoring pressure gauge is released to the interface side of the monitoring pressure gauge through the pressure monitoring chamber pressure relief hole 19 to achieve pressure balance between the two. The pressure on the pressure calibration system side is the atmospheric pressure. Under the action of the working pressure of the gas storage tank, the piston continues to slide towards the pressure calibration system interface side. When the second O-ring 9 reaches the other side of the through-hole of the monitoring pressure gauge (the right side of the through-hole in the figure), the monitoring pressure gauge side is cut off from the pressure calibration system side, and the three-way valve enters the "daily detection position".

[0035] 1. Installation of the three-way valve

[0036] Before the start of the gas supply or pneumatic system or during system maintenance, connect or modify the three-way valve of the present utility model to the gas storage tank. When the system is started and used, the pressure of the gas storage tank increases. Under the action of the pressure difference formed by this pressure and the ambient atmospheric pressure, the piston is pushed towards the pressure calibration system side. When the piston reaches the limit platform, the three-way valve is in the daily monitoring position, and the gas storage tank is connected to the daily monitoring pressure gauge through the calibration chamber, the pressure monitoring chamber vent hole, and the vent hole, and the monitoring pressure gauge displays the pressure of the gas storage tank.

[0037] During calibration, the pressure calibration system realizes the switching of the three-way valve between the pressure calibration position and the daily monitoring position by screwing on or off the quick connector with a high-pressure hose.

[0038] 2. Use of the three-way valve in in-situ calibration

[0039] The in-situ calibration of the monitoring pressure gauge in the gas storage tank or pipeline of the gas supply or pneumatic system can be carried out by using the three-way valve of the present utility model. Match the strength of the designed three-way valve with the range of the gas storage tank pressure gauge or the maximum designed pressure of the gas (power) system. Use the working pressure of the gas storage tank and the limit of the external joint on the pressure calibration system side to make it work in the daily pressure monitoring position or the pressure calibration position, and realize the function switching between daily pressure monitoring and monitoring pressure calibration.

Claims

1. A three-way valve for realizing in-situ calibration of a pressure gauge, comprising a valve body (1), a piston (2) fitted to the inner wall of the valve body (1), a gas storage tank interface (3), a monitoring pressure gauge interface (6), and a pressure calibration system interface (7). The gas storage tank interface (3) and the pressure calibration system interface (7) are located at both ends of the valve body, and the monitoring pressure gauge interface (6) is located on the side of the valve body. It is characterized in that, the through-hole of the monitoring pressure gauge interface (6) is filled with copper sound-absorbing material (8); the piston (2) is provided with two cavities. The side close to the gas storage tank interface (3) is a pressure monitoring cavity (12), and the side close to the pressure calibration system interface (7) is a pressure calibration cavity (13). Each of the two cavities is provided with a vent hole leading to the valve body. Correspondingly, the piston is divided into two parts: a pressure monitoring side and a pressure calibration side; an annular sealing groove and a matching O-ring (9) are provided on the outer wall at the junction of the two cavities; the three-way valve includes two working positions. One is the daily detection position. At this time, the piston is away from the gas storage tank interface (3), and the vent hole of the pressure monitoring cavity (12) leads to the monitoring pressure gauge interface. The other is the in-situ calibration position. At this time, the piston is close to the gas storage tank interface (3), and the vent hole of the pressure calibration cavity (13) leads to the pressure gauge interface.

2. The three-way valve according to claim 1, wherein The two cavities of the piston (2) are respectively provided with relief holes leading to the valve body.

3. The three-way valve according to claim 1, wherein A filter disc (11) is provided at the end of the pressure calibration cavity (13) of the piston.

4. The three-way valve according to claim 3, characterized in that, The filter disc (11) is made of copper sound-absorbing material.

5. The three-way valve according to claim 1, characterized in that, A color ring (14) is designed at the outer wall end of the pressure calibration side of the piston. When the three-way valve is in the daily detection position, it is in an exposed state, used to indicate whether the three-way valve is in the daily detection position.

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