Replacement structure and gas pipeline vacuum replacement positive and negative pressure balance command device

Abstract

The utility model relates to a replacement structure and gas pipeline vacuum replacement positive and negative pressure balance command device, the replacement structure comprises a gas inlet cavity and a gas outlet cavity which are connected, a leather membrane and a balance membrane are arranged in the gas inlet cavity from top to bottom, and the leather membrane and the balance membrane divide the gas inlet cavity into a first cavity, a second cavity and a third cavity from top to bottom. A spring is arranged between the upper wall of the first cavity and the leather membrane, a valve rod is arranged at the lower end of the leather membrane, the valve rod penetrates through the balance membrane and extends into the air outlet cavity, one end of the valve rod can abut against and seal the valve port, the second cavity is communicated with the air outlet cavity through an auxiliary path, a first valve is arranged on the first cavity, and a second valve is arranged on the second cavity. A second valve is arranged on the third cavity, a third valve is arranged on the gas outlet cavity, and the gas pipeline vacuum replacement positive and negative pressure balance command device comprises a first replacement structure and a second replacement structure. The device ensures the safety and reliability of normal operation of the pipe network, improves the working efficiency, and saves manpower and operation and maintenance resource cost.

Description

Technical Field

[0001] The utility model relates to the technical field of gas supply, in particular to a replacement structure and a gas pipeline vacuum replacement positive and negative pressure balance command device. Background Art

[0002] In existing gas pipe replacement operations for residential buildings (also known as courtyard pipes), direct replacement technology utilizes a technique that uses the positive pressure gas output from the main pressure regulator in the regional pressure regulating box to directly discharge the air from the terminal low-pressure riser vent. This pushes and displaces the air within each low-pressure riser, bringing the gas concentration within the gas pipeline to the set standard and achieving the replacement purpose. However, the replacement process requires high-altitude operation because the terminal vent of the low-pressure pipe is located outside the building's exterior wall. Alternatively, due to structural limitations (such as in a courtyard building), the terminal vent must be placed in a poorly ventilated location. This construction operation poses certain safety risks and increases the workload of natural gas replacement.

[0003] Negative pressure displacement can be performed using a pressure regulating box in the pipe network area. Air is extracted from residential building gas pipes (also known as courtyard pipes) and then replaced with positive pressure gas. This process, which is not restricted by the construction environment, reduces safety risks and improves work efficiency. However, during the vacuum and negative pressure replacement process, when the replaced pipe is evacuated to a negative pressure of 0.1 MPa, a valve opens to allow positive pressure to enter the replaced pipe through the pressure regulator. At this point, the inlet pressure of the pressure regulator is positive, while the outlet pressure changes from the positive pressure output within the pressure regulating function range to negative pressure. During this stage, the pressure absorbed by the negative pressure at the pressure regulator outlet reaches 0.1 MPa + the outlet set pressure. This phenomenon exceeds the normal use of the pressure regulator and poses a risk of damage to the pressure regulator's main diaphragm. If improperly controlled, the risk can be so high that the pressure regulator structural components will lose their function and enter a straight-through state. At this time, the positive pressure of 0.27 MPa + the negative pressure of 0.1 MPa will reach 0.37 MPa at the user end, with very serious consequences. The current control technology relies on manual, slow valve opening, with immediate adjustments based on experience and observation of pressure changes displayed on the pressure gauge. This technology presents technical flaws and uncontrollable factors. Therefore, it is necessary to develop a gas pipeline vacuum displacement positive and negative pressure balance control device to address the technical challenges of negative pressure displacement. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides a gas pipeline vacuum replacement positive and negative pressure balance command device. Under the interaction of the main components of the new device technology, namely the balancer, the commander, the one-way valve and the throttle valve, the unreasonable old process defect that the negative pressure causes the pressure of the pressure regulator outlet to rise, which causes the pressure regulator to exceed the normal use scope, is overcome. The important link in the vacuum replacement technology is upgraded from manual control to automatic control of the mechanical structure, thereby improving the vacuum replacement technology.

[0005] The technical solution of the present utility model is: a replacement structure, comprising a connected air inlet chamber and an air outlet chamber, wherein a membrane and a balance membrane are provided above and below the air inlet chamber, and the membrane and the balance membrane divide the air inlet chamber into a first chamber, a second chamber and a third chamber from top to bottom, a valve port is provided between the third chamber and the air outlet chamber, a spring is provided between the upper wall of the first chamber and the membrane, a valve stem is provided at the lower end of the membrane, the valve stem passes through the balance membrane and extends into the air outlet chamber, one end of the valve stem can abut and close the valve port, the second chamber and the air outlet chamber are connected through an auxiliary road, a first valve is provided on the first chamber, a second valve is provided on the third chamber, and a third valve is provided on the air outlet chamber.

[0006] A gas pipeline vacuum replacement positive and negative pressure balance command device includes an air inlet pipe, an air outlet pipe, a first replacement structure, a second replacement structure, a throttle valve and a one-way valve. The air inlet pipe is connected to the second valve of the first replacement structure and the second valve of the second replacement structure through a pipe. One end of the throttle valve is connected to the third valve of the first replacement structure through a pipe, and the other end is connected to the first valve and the one-way valve of the second replacement structure through a pipe. The one-way valve is connected to the air outlet cavity of the second replacement structure through a pipe. The third valve of the second replacement structure is connected to the air outlet pipe through a pipe. The first valve of the first replacement structure is normally open, and the flow direction of the one-way valve is toward the air outlet cavity of the second replacement structure.

[0007] Furthermore, the air inlet pipe is provided with an inlet valve, and the air outlet pipe is provided with an outlet valve.

[0008] Compared with existing technologies, the advantages of this utility model are: it uses an auxiliary line connection within the regional pressure regulating box to isolate the main pressure regulator by closing valves at the front and rear ends. After the auxiliary line has achieved positive and negative pressure balance, the main pressure regulator resumes normal operation. This eliminates the risk of damage to the main pressure regulator's structural components and main diaphragm, and upgrades the key link in vacuum replacement technology from manual control to automatic mechanical control, making the vacuum replacement process safer and more efficient. This device technology ensures the safe and reliable normal operation of the pipeline network, improves work efficiency, saves manpower, reduces the cost of operation and maintenance resources, and improves production efficiency and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0010] Figure 1 It is a schematic diagram of the replacement structure of the utility model;

[0011] Figure 2This is a working principle diagram of the utility model;

[0012] Figure 3 This is a diagram of the usage state of the first stage of the utility model;

[0013] Figure 4 This is a diagram of the usage state of the second stage of the utility model;

[0014] Figure 5 This is a usage state diagram for the third stage of the utility model;

[0015] Figure 6 This is a usage state diagram for the fourth stage of the utility model;

[0016] Figure 7 This is a usage status diagram of the fifth stage of the utility model.

[0017] Among them: 1. Air inlet chamber; 101. First chamber; 102. Second chamber; 103. Third chamber; 2. Air outlet chamber; 3. Membrane; 4. Balancing membrane; 5. Spring; 6. Valve stem; 7. Valve port; 8. First valve; 9. Second valve; 10. Third valve; 11. Auxiliary line; 21. Control device; 22. Balancer; 23. Throttle valve; 24. One-way valve; 25. Air inlet pipe; 26. Air outlet pipe; 27. Inlet valve; 28. Outlet valve; 29. Courtyard pipe network. DETAILED DESCRIPTION

[0018] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation method, structure, characteristics and effects of the present invention in combination with the accompanying drawings and preferred embodiments.

[0019] like Figure 1-2 As shown, a gas pipeline vacuum displacement positive and negative pressure balancing command device includes a first displacement structure and a second displacement structure. The first displacement structure is called a commander 21, and the second displacement structure is called a balancer 22. The first chamber 101 and the second chamber 102 are the upper and lower chambers of the membrane 3, and the second chamber 102 and the third chamber 103 are the upper and lower chambers of the balancing membrane 4.

[0020] Before replacing the natural gas in the building, a gas pipeline vacuum replacement positive and negative pressure balance command device is connected to the vent position in front of the medium-pressure valve and behind the low-pressure valve of the main pressure regulator in the pipeline area, and the air of about 0.1MPA in the low-pressure courtyard pipeline 29 in the area to be replaced is extracted to form a vacuum negative pressure state in the pipeline. The vacuum replacement positive and negative pressure balance command device then completes the automatic replacement process and then disconnects. After the disconnection is completed, the main pressure regulator will resume normal gas supply.

[0021] The technical concept of this device is: when the air in the courtyard pipe network 29 is extracted and connected to this device for replacement, first open the device outlet valve 28 to connect it to the pipe that needs to be replaced. At this time, the one-way valve 24 is in an open state with high inlet pressure and low outlet pressure. The upper and lower chambers of the membrane 3 in the balancer 22 are also in the same negative pressure environment, forming equal pressure to eliminate the adverse effects of negative pressure. Only the tension of the upper chamber spring 5 pushes the valve stem 6 to keep the valve port 7 in the balancer 22 open. Then slowly open the device inlet valve 27, and the relatively high medium pressure at the inlet flows into the low-pressure outlet end through the valve port 7 of the balancer 22. The lower chamber of the membrane 3 in the balancer 22 has a relatively high pressure, and the force drives the valve stem 6 upward to close the valve. The one-way valve 24 is closed at this time due to the low inlet pressure and high outlet pressure. The high lower pressure and low upper pressure of the membrane 3 in the balancer 22 offset the upper chamber spring. Due to the tension of the spring 5, there is no pressure output at the outlet of the balancer 22; the commander 21 adjusts the relatively high pressure at the inlet to a low pressure that can control the balancer 22, and enters the upper cavity of the endothelial membrane 3 of the balancer 22 through the throttle valve 23, pushing the endothelial membrane 3 downward to drive the valve stem 6 and the valve to open. At this time, the one-way valve 24 opens because the outlet pressure is lower than the inlet pressure, and the valve port 7 in the balancer 22 opens to allow the relatively high pressure to flow out. The one-way valve 24 closes again at this time because the outlet pressure is higher than the inlet pressure, and the endothelial membrane 3 of the balancer 22 is formed again with high pressure at the bottom and low pressure at the top, which offsets the tension of the upper cavity spring 5 and the outlet pressure of the commander 21, and there is no pressure output at the outlet of the balancer 22 again; at this time, the output pressure of the commander 21 at the inlet of the one-way valve 24 is higher than the outlet pressure and it opens again. The outlet pressure of the balancer 22 is low, and the pressure balance between the upper and lower cavities of the endothelial membrane 3 is broken again. Under the opening and closing action of the one-way valve 24, the inner membrane 3 of the balancer 22 alternates between high and low pressures in the upper and lower chambers, and the constant oscillating motion drives the valve stem 6 to open and close the valve port 7 at a frequency. The outlet of the balancer 22 continuously and alternately outputs pressure, automatically replacing it until the set pressure value is reached, and the inner membrane 3 of the balancer 22 is in balance, and then the pressure output stops. Because the output flow of the controller 21 is fixed, a higher flow rate causes the movement frequency of the membrane 3 of the balancer 22 to increase, causing surge in the system, which requires adjustment of the throttle valve 23 to eliminate the surge. Through the alternating action of the main components, the balancer 22, the controller 21, the one-way valve 24, and the throttle valve 23, automatic replacement is completed, completing the entire process flow and eliminating the negative effects of manual replacement.

[0022] Description of the working method of this utility model:

[0023] like Figure 3 As shown, the first stage adopts the following steps:

[0024] Step 1: The inlet and outlet valves 27 of the pipe network area pressure regulator RX100 are closed, and the courtyard pipe network 29 behind the valve is evacuated to 0.091 MPa (atmospheric pressure is about 0.1 MPa) by a vacuum pump.

[0025] Step 2: The inlet and outlet valves 27 of the positive and negative pressure balance control device remain closed, and the vacuum replacement process enters the hot standby state;

[0026] like Figure 4 As shown, the second stage adopts the following steps:

[0027] Step 3: The inlet valve 27 of the positive and negative pressure balance command device is closed, and the outlet valve 28 is slowly opened. At this time, the one-way valve 24 is "positively conductive", and the first chamber 101 and the second chamber 102 on both sides of the membrane 3 of the balancer 22 are in an isobaric state under the air pressure condition;

[0028] Step 4: Under the action of the spring 5, the balancer 22 moves the valve stem 6 downward, and the valve is in the "fully open" state;

[0029] Step 5: Open the inlet valve 27 of the positive and negative pressure balance command device, and the airflow presents a "medium pressure direct state", and the injected airflow presents a medium pressure and large flow;

[0030] like Figure 5 As shown, the third stage adopts the following steps:

[0031] Step 6: When the pressure of the downstream courtyard pipe network 29 changes from "negative pressure" to "positive pressure", the opening and closing state of the one-way valve 24 is determined by the system dynamic pressure value;

[0032] Step 7: When the pressure of the downstream courtyard pipe network 29 exceeds the pressure of the positive and negative pressure balance control device 21 and the output pressure is 2500 Pa, the one-way valve 24 is closed;

[0033] like Figure 6 As shown, the fourth stage adopts the following steps:

[0034] Step 8: When the one-way valve 24 is closed, the force on the upper and lower chambers of the membrane 3 of the balancer 22 is converted to (gauge pressure) 2500 Pa + the force of the spring 5;

[0035] Step 9: The valve stem 6 of the balancer 22 moves upward, the opening of the valve port 7 decreases, and the amount of air passing through decreases;

[0036] Step 10: When the pressure of the downstream courtyard pipe network 29 rises to more than (gauge pressure) 2500Pa + spring 5 force + closing pressure, the valve port 7 of the balancer 22 is closed and the output is zero;

[0037] Step 11: The positive and negative pressure balance command device task is completed;

[0038] like Figure 7 As shown, the fifth stage adopts the following steps:

[0039] Step 12, cut off the positive and negative pressure balance command device and close the inlet and outlet valves 27;

[0040] Step 13: Connect the RX100 station network area pressure regulator, and then fine-tune the relief valve to the "normal gas supply state".

[0041] The test results are as follows: about 95% of the air in the natural gas pipeline to be replaced is extracted using a negative pressure vacuum, and then natural gas is injected for direct replacement. Since there is a large pressure difference in the conversion process between negative and positive pressures when the valve is opened for replacement, it will cause damage to the membrane 3 and structural parts of the pressure regulator. A branch line is used to connect the positive and negative pressure balancing command device. Under the interaction of the balancer 22, the command device 21, the one-way valve 24, and the throttle valve 23, the purpose of balancing the positive and negative pressures is achieved without damaging the pressure regulator. After the positive and negative pressure balance is completed, the replacement reaches the replacement requirement of a CH4 (methane) concentration ratio of more than 95VOL%. The specific operation of the entire process is relatively simple, which reduces the safety risks of the replacement process, shortens the construction process, improves the flexibility of construction, saves a lot of human resource costs, improves work efficiency, and solves process defects with high safety risks.

[0042] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A displacement structure comprising an air inlet cavity and an air outlet cavity connected to each other, characterized in that: A membrane and a balance membrane are provided above and below the air inlet chamber, and the membrane and the balance membrane divide the air inlet chamber into a first chamber, a second chamber and a third chamber from top to bottom. A valve port is provided between the third chamber and the air outlet chamber, a spring is provided between the upper wall of the first chamber and the membrane, a valve stem is provided at the lower end of the membrane, the valve stem passes through the balance membrane and extends into the air outlet chamber, one end of the valve stem can abut and close the valve port, the second chamber and the air outlet chamber are connected through an auxiliary road, a first valve is provided on the first chamber, a second valve is provided on the third chamber, and a third valve is provided on the air outlet chamber.

2. A gas pipeline vacuum displacement positive and negative pressure balance control device using the displacement structure of claim 1, comprising an air inlet pipe, an air outlet pipe, a first displacement structure, a second displacement structure, a throttle valve, and a one-way valve, characterized in that: The air intake pipe is connected to the second valve of the first replacement structure and the second valve of the second replacement structure through a pipeline. One end of the throttle valve is connected to the third valve of the first replacement structure through a pipeline, and the other end is connected to the first valve and the one-way valve of the second replacement structure through a pipeline. The one-way valve is connected to the air outlet cavity of the second replacement structure through a pipeline, and the third valve of the second replacement structure is connected to the air outlet pipe through a pipeline. The first valve of the first replacement structure is normally open, and the flow direction of the one-way valve is toward the air outlet cavity of the second replacement structure.

3. The gas pipeline vacuum replacement positive and negative pressure balance command device according to claim 2, characterized in that: The air inlet pipe is provided with an inlet valve, and the air outlet pipe is provided with an outlet valve.

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