Manhole cover for pressurization test cabin

Abstract

The invention discloses a manhole cover for a pressurization test cabin, and relates to the related technical field of manhole covers. The manhole cover comprises a cover body used for sealing a manhole, a filling hole is formed in the surface of the cover body, a pressurizing pipe is fixedly connected to the outer side wall of the filling hole and communicates with an outlet of external air supply equipment, a pressure relief hole is further formed in the surface of the cover body, a pressure relief pipe is fixedly connected to the inner side wall of the pressure relief hole, and a pressure relief valve is fixedly installed on the pressure relief pipe. A first control valve is fixedly installed outside the pressurizing pipe, and a linkage assembly is arranged between a valve element operation part of the first control valve and a valve element operation part of the pressure release valve. The pressure release valve is arranged on the side, close to the interior of the cabin, of the cover body, so that when people are trapped in the cabin, the trapped people can automatically open the pressure release valve in the cabin, air in the cabin is exhausted outwards, the pressure rising trend in the cabin is slowed down or stopped, time is won for rescue, or the pressure in the cabin is reduced, and self-rescue is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field related to manhole covers, and in particular relates to a manhole cover for a pressurized test cabin. Background Art

[0002] At present, when the shipbuilding industry conducts cabin air tightness test, the door holes and other holes are first closed or blocked with the original cabin door cover, and one door hole is reserved for installing the temporary cabin air tightness test tool door cover. After the tool is closed, a temporary compression air duct is pulled and connected to the tool inflation interface pipe. The ball valve is opened to inflate the cabin and then the ball valve is closed to stop inflation. After the pressure stabilizes, observe whether the pressure gauge and pressure water column on the tool are maintained at the corresponding air pressure to verify whether the cabin tightness test is successful or not.

[0003] At present, many ship cabins have very large volumes and very complex structures. Before sealing the cabin, the inspection of the personnel in the cabin mainly depends on the responsibility of the inspectors. It is often the case that the personnel remaining in the cabin are not properly checked before the cabin is sealed and inflated, resulting in the situation that the personnel are trapped in the cabin and inflated. When the inflation begins, the personnel trapped in the completely closed cabin cannot communicate with the outside world after discovering the abnormality, which is very likely to cause casualties. To this end, we provide a manhole cover for the pressurized test cabin to solve the above technical problems. Summary of the invention

[0004] The object of the present invention is to provide a manhole cover for a pressurized test chamber, which solves the problems in the above technical background through the specific structural design of the cover body.

[0005] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0006] The present invention is a manhole cover for a pressurized test chamber, comprising a cover body for sealing the manhole, a filling hole is provided on the surface of the cover body, a pressurizing pipe is fixedly connected to the outer wall of the filling hole, and the pressurizing pipe is communicated with the outlet of an external gas supply device, a pressure relief hole is also provided on the surface of the cover body, a pressure relief pipe is fixedly connected to the inner wall of the pressure relief hole, and a pressure relief valve is fixedly installed on the pressure relief pipe.

[0007] The present invention is further configured as follows: a first control valve is fixedly installed on the outside of the pressurizing pipe, the engaging states of the first control valve and the pressure relief valve are opposite, and a linkage component is provided between the valve core operating part of the first control valve and the valve core operating part of the pressure relief valve; the first control valve and the pressure relief valve are both ball valves, the rotation trajectory plane of the valve core passage in the first control valve is parallel to the rotation trajectory plane of the valve core passage in the pressure relief valve, the valve body passages of the first control valve and the pressure relief valve are parallel, and the valve core operating rod of the first control valve is perpendicular to the projection of the axial extension line of the valve core passage in the pressure relief valve on the rotation trajectory plane.

[0008] The present invention is further configured such that the valve core operating rod of the first control valve is parallel to the valve core operating rod of the pressure relief valve, a side surface of the valve core operating rod of the first control valve is fixedly connected to a first transmission wheel, a side surface of the valve core operating rod of the pressure relief valve is fixedly connected to a second transmission wheel, a transmission member is arranged between the first transmission wheel and the second transmission wheel, the transmission member is adapted to the first transmission wheel and the second transmission wheel, and an operating handle is fixedly connected to the valve core operating rod of the pressure relief valve; a mounting hole is provided on the surface of the cover body, the transmission member is slidably arranged inside the mounting hole, a protective shell is fixedly installed on the inner wall of the cover body, the protective shell coincides with the mounting hole, and the second transmission wheel is located inside the protective shell, a through hole is provided on the surface of the protective shell for the valve core operating rod of the pressure relief valve to pass through, and the valve core operating rod of the pressure relief valve passes through the through hole.

[0009] The present invention is further configured as follows: a first air duct is fixedly connected to the inner wall of the filling hole, one end of the first air duct is connected to the filling hole, and the other end of the first air duct is connected to the first alarm unit; a second air duct is fixedly connected to the outer wall of the pressure relief hole, one end of the second air duct is connected to the pressure relief hole, and the other end of the second air duct is connected to the second alarm unit.

[0010] The present invention is further configured as follows: the surface of the cover body is respectively provided with a first detection hole and a second detection hole, a pressure gauge is fixedly installed on the outer wall of the first detection hole; a third air duct is fixedly connected to the outer wall of the second detection hole, one end of the third air duct is communicated with the second detection hole, the other end of the third air duct is fixedly connected to a liquid storage tank, a liquid duct is fixedly connected to the surface of the liquid storage tank, the lower end of the liquid duct is located inside the liquid storage tank, the lower end of the liquid duct is located below the liquid level in the liquid storage tank, and the lower end of the air duct is located above the liquid level inside the liquid storage tank; a third control valve is fixedly installed on the third air duct.

[0011] The present invention is further configured such that the first alarm unit and the second alarm unit both include an air pressure detection module, an information sending module, a control module and a receiver, the air pressure detection modules are respectively fixedly installed inside the pressure relief hole and the filling hole, and the air pressure detection modules are used to sense the air pressure values ​​inside the pressure relief hole and the filling hole.

[0012] The present invention has the following beneficial effects:

[0013] The present invention arranges the pressure relief valve on the inner side of the cover body, that is, on the inner side of the cover body close to the cabin. If people are trapped in the cabin, the trapped people can open the pressure relief valve by themselves in the cabin to discharge the air in the cabin to the outside, which can slow down or stop the pressure increase trend in the cabin, thereby buying time for rescue, or reducing the pressure inside the cabin to achieve self-rescue.

[0014] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0016] Figure 1 The figure is a schematic diagram of the structure of a manhole cover for a pressurized test chamber.

[0017] Figure 2 It is a structural schematic diagram of another angle of the present invention.

[0018] Figure 3 for Figure 2 A local enlarged schematic diagram of point A in the middle.

[0019] Figure 4 It is a structural schematic diagram of another angle of the present invention.

[0020] Figure 5 It is a partial structural schematic diagram of the present invention.

[0021] Figure 6 It is a longitudinal structural cross-sectional view of the present invention.

[0022] Figure 7 It is a flow chart of the alarm unit in the present invention.

[0023] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0024] 1-cover body, 2-filling hole, 3-pressurization pipe, 4-pressure relief hole, 5-pressure relief pipe, 6-pressure relief valve, 7-first control valve, 8-first transmission wheel, 9-second transmission wheel, 10-transmission member, 11-protective shell, 12-first air pipe, 13-first alarm unit, 14-second air pipe, 15-second alarm unit, 16-second control valve, 17-pressure gauge, 18-third air pipe, 19-liquid storage tank, 20-liquid pipe, 21-third control valve. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] For specific implementations, see Figure 1-7 The present invention is a manhole cover for a pressurized test chamber, comprising a cover body 1 for sealing the manhole. Specifically, a filling hole 2 is provided on the surface of the cover body 1, a pressurizing pipe 3 is fixedly connected to the outer wall of the filling hole 2, and the pressurizing pipe 3 is communicated with the outlet of an external gas supply device. A pressure relief hole 4 is also provided on the surface of the cover body 1, a pressure relief pipe 5 is fixedly connected to the inner wall of the pressure relief hole 4, and a pressure relief valve 6 is fixedly installed on the pressure relief pipe 5.

[0027] Furthermore, a first control valve 7 is fixedly installed on the outside of the pressurizing pipe 3, and the engaging states of the first control valve 7 and the pressure relief valve 6 are opposite, and a linkage component is provided between the valve core operating part of the first control valve 7 and the valve core operating part of the pressure relief valve 6; the first control valve 7 and the pressure relief valve 6 are both ball valves, and the rotation trajectory plane of the valve core passage in the first control valve 7 is parallel to the rotation trajectory plane of the valve core passage in the pressure relief valve 6, the valve body passages of the first control valve 7 and the pressure relief valve 6 are parallel, and the valve core operating rod of the first control valve 7 is perpendicular to the projection of the axial extension line of the valve core passage in the pressure relief valve 6 on the rotation trajectory plane.

[0028] Furthermore, the valve core operating rod of the first control valve 7 is parallel to the valve core operating rod of the pressure relief valve 6, and a first transmission wheel 8 is fixedly connected to one side of the valve core operating rod of the first control valve 7, and a second transmission wheel 9 is fixedly connected to one side of the valve core operating rod of the pressure relief valve 6, and a transmission member 10 is arranged between the first transmission wheel 8 and the second transmission wheel 9, and the transmission member 10 is adapted to the first transmission wheel 8 and the second transmission wheel 9, and an operating handle is fixedly connected to the valve core operating rod of the pressure relief valve 6; a mounting hole is opened on the surface of the cover body 1, and the transmission member 10 is slidably arranged inside the mounting hole, and a protective shell 11 is fixedly installed on the inner wall of the cover body 1, the protective shell 11 coincides with the mounting hole, and the second transmission wheel 9 is located inside the protective shell 11, and a through hole is opened on the surface of the protective shell 11 for the valve core operating rod of the pressure relief valve 6 to pass through, and the valve core operating rod of the pressure relief valve 6 passes through the through hole.

[0029] Furthermore, a first air duct 12 is fixedly connected to the inner wall of the filling hole 2, one end of the first air duct 12 is connected to the filling hole 2, and the other end of the first air duct 12 is connected to the first alarm unit 13; a second air duct 14 is fixedly connected to the outer wall of the pressure relief hole 4, one end of the second air duct 14 is connected to the pressure relief hole 4, and the other end of the second air duct 14 is connected to the second alarm unit 15.

[0030] Furthermore, the surface of the cover body 1 is respectively provided with a first detection hole and a second detection hole, and a pressure gauge 17 is fixedly installed on the outer wall of the first detection hole; a third air duct 18 is fixedly connected to the outer wall of the second detection hole, one end of the third air duct 18 is communicated with the second detection hole, and the other end of the third air duct 18 is fixedly connected to a liquid storage tank 19, and a liquid guide tube 20 is fixedly connected to the surface of the liquid storage tank 19, the lower end of the liquid guide tube 20 is located inside the liquid storage tank 19, the lower end of the liquid guide tube 20 is located below the liquid level in the liquid storage tank, and the lower end of the air guide tube is located above the liquid level inside the liquid storage tank 19; a third control valve 21 is fixedly installed on the third air duct 18.

[0031] Furthermore, the first alarm unit 13 and the second alarm unit 15 both include an air pressure detection module, an information sending module, a control module and a receiver. The air pressure detection modules are fixedly installed inside the pressure relief hole 4 and the filling hole 2 respectively. The air pressure detection modules are used to sense the air pressure values ​​inside the pressure relief hole 4 and the filling hole 2.

[0032] The operation process of this embodiment is as follows: the cover body 1 is used to close the manhole of the cabin, so that the cabin is in a closed state, the pressurized pipe 3 can be connected to the outlet end of the air compressor or other air supply equipment, and can inject compressed air into the closed cabin to increase the pressure inside the cabin, and the pressure relief valve 6 is installed on the pressure relief pipe 5, and the pressure relief pipe 5 is connected to the pressure relief hole 4. When the pressure relief valve 6 is in an open state, the pressure relief pipe 5 and the pressure relief hole 4 will constitute a channel for the air inside the cabin to flow outward, which is used for the air inside the cabin to be discharged outward, so that the pressure increase trend inside the cabin is slowed down or stopped, or even the pressure inside the cabin is reduced; wherein, the pressure relief valve 6 is located on the inner side of the cover body 1, that is, on the side of the cover body 1 close to the cabin. When people are trapped in the cabin, the trapped people can open the pressure relief valve 6 by themselves in the cabin to discharge the air in the cabin outward, which can slow down or stop the pressure increase trend in the cabin, buy time for rescue, or reduce the pressure inside the cabin to achieve self-rescue.

[0033] When changing the opening and closing state of the first control valve 7 or the pressure relief valve 6, the opening and closing state of the pressure relief valve 6 or the first control valve 7 is changed through the linkage component; when the first control valve 7 is in the open state, the pressurized pipe 3 will serve as a passage for air to enter the cabin, and when the first control valve 7 is in the closed state, the pressurized pipe 3 can be blocked, so that the air supply equipment stops supplying air to the cabin; that is, the valve core operating part of the first control valve 7 and the valve core operating part of the pressure relief valve 6 will be used to control the internal valve cores of the two to change the opening and closing state of the first control valve 7 and the pressure relief valve 6, and the opening and closing state of the first control valve 7 and the pressure relief valve 6 The opening and closing states of the pressure relief valve 6 are opposite, and the opening and closing states of the first control valve 7 and the pressure relief valve 6 can be linked and controlled by the linkage component and the valve core operating parts of the two. When the first control valve 7 is in the open state and the pressure relief valve 6 is in the closed state, the interior of the cabin can be pressurized. If the trapped personnel opens the pressure relief valve 6 to relieve the pressure in the cabin during the pressurization process, the first control valve 7 will be closed, that is, the pressurization pipe 3 is blocked, so that the air supply equipment stops supplying air to the interior of the cabin, that is, there is no air replenishment in the cabin during the pressure relief process, and the pressure inside the cabin will gradually decrease.

[0034] The ball valve can open or close the valve body passage by rotating the valve core 90°. The valve body passages inside the first control valve 7 and the pressure relief valve 6 are parallel, and the projections of the axial extension lines of the valve core passages of the two on the rotation trajectory plane intersect vertically. The valve core passages of the first control valve 7 and the pressure relief valve 6 will be in a 90° intersecting state, that is, when the first control valve 7 is in a closed state, the pressure relief valve 6 is in an open state. When the valve core operating rod rotates, it will drive the valve core to rotate, thereby controlling the opening and closing of the first control valve 7 or the pressure relief valve 6. The first control valve 7 and the pressure relief valve 6 are in a 90° intersecting state. The first transmission wheel 8 and the second transmission wheel 9 are respectively installed on the valve core operating rod of the valve 7 and the valve core operating rod of the pressure relief valve 6, and the first transmission wheel 8 and the second transmission wheel 9 are connected by a transmission member 10. When the first transmission wheel 8 or the second transmission wheel 9 rotates, the second transmission wheel 9 or the first transmission wheel 8 will be driven to rotate. Due to the synchronous rotation, when the first transmission wheel 8 or the second transmission wheel 9 rotates 90°, the second transmission wheel 9 or the first transmission wheel 8 will also rotate 90°, thereby realizing the linkage control of the first control valve 7 and the pressure relief valve 6.

[0035] The first transmission wheel 8 and the second transmission wheel 9 are gear structures, and the transmission member 10 is a rack structure. When the first transmission wheel 8 or the second transmission wheel 9 rotates, the second transmission wheel 9 or the first transmission wheel 8 can be pushed to rotate by the rack structure to realize the synchronous rotation of the first transmission wheel 8 and the second transmission wheel 9, wherein the mounting hole serves as a sliding passage for the rack, and the protective shell 11 covers the outside of the mounting hole, which can be closed. The valve core operating rod of the pressure relief valve 6 passes through the protective shell 11 and rotates in coordination. The sealing coordination can be achieved by setting a sealing ring and the like, so that the cover body 1 maintains the sealing performance; or the first transmission wheel 8 and the second transmission wheel 9 are both pulleys, and the transmission member 10 is a transmission belt, constituting a pulley transmission structure; or the first transmission wheel 8 and the second transmission wheel 9 are sprockets, and the transmission member 10 is a transmission chain, constituting a sprocket transmission structure, both of which can realize the synchronous transmission between the first transmission wheel 8 and the second transmission wheel 9, and the mounting hole will serve as the installation space of the transmission belt or the transmission chain.

[0036] The first alarm unit 13 is located on the inner side of the cover body 1 and cooperates with the filling hole 2 through the first air duct 12. When air is introduced into the cabin, the incoming air will act on the first alarm unit 13, and the first alarm unit 13 will send a warning message to the inside of the cabin to warn the possible trapped persons, that is, to warn the possible trapped persons at the early stage of the dangerous situation, thereby reducing the harm caused to the possible trapped persons; the second alarm unit 15 is located on the outer side of the cover body 1 and cooperates with the pressure relief hole 4 through the second air duct 14. After the trapped person opens the pressure relief valve 6, the air in the cabin will be discharged from the pressure relief hole 4 through the second air duct 14 and act on the second alarm unit 15. The second alarm unit 15 will send a warning message to the outside of the cabin, feedback the actions of the trapped persons to the outside world, and remind other staff members.

[0037] The air pressure detection module can be an air pressure sensor. When air flows in the pressure relief hole 4 and the filling hole 2, pressure changes will occur. A pressure value, such as standard atmospheric pressure, can be preset inside the control module. When the air pressure value input by the air pressure detection module is lower or higher than the standard atmospheric pressure value, the control module sends information to the outside through the information sending module, and the receiver gives feedback prompts based on the received information; according to usage requirements, the prompter can be a handheld terminal, and the information sending module is a wireless signal sending module; the prompter is a buzzer or siren that can emit sound reminders; the prompter is a warning light that can emit light reminders; the prompter can also be a combination of a warning light and a buzzer or siren, which can give sound and light reminders at the same time.

[0038] During the pressurization stage of the test process, the first control valve 7 and the second control valve 16 are both in the open state. During the pressure maintaining stage, the first control valve 7 remains in the open state, and the second control valve 16 is in the closed state, that is, the pressurization pipeline is closed by the second control valve 16.

[0039] The air pressure change in the cabin can be directly observed through the barometer 17, and the third air duct 18 can be controlled to be on and off by the third control valve 21. The third control valve 21 is in a normally closed state. When it is necessary to calibrate the detection value with the barometer 17, the third control valve 21 is opened to allow the air in the cabin to enter the liquid storage tank 19. The liquid in the liquid storage tank 19 will rise along the liquid duct 20 under the action of air pressure. By observing the height of the liquid in the liquid duct 20, the pressure in the cabin can be calculated for calibration with the detection value of the pressure gauge.

[0040] During the pressurization process, the third control valve 21 can remain in a normally open state, wherein the height of the liquid guiding tube 20 matches the pressure of the pressure test; that is, the height of the liquid guiding tube 20 matches the set pressure threshold maximum value. When the pressure exceeds the set pressure threshold maximum value, the pressure can push the liquid in the liquid storage tank 19 out of the upper end of the liquid guiding tube 20, and the pressure can be actively relieved through the liquid guiding tube 20. The liquid guiding tube 20 has the function of pressure detection and verification, and also has the function of overpressure relief. In addition, it can also avoid overpressure accidents caused by human operating errors during the test.

[0041] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0042] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A manhole cover for a pressurized test chamber, comprising a cover body (1) for sealing the manhole, characterized in that: The cover body (1) is provided with a filling hole (2) on its surface, a pressurizing pipe (3) is fixedly connected to the outer wall of the filling hole (2), and the pressurizing pipe (3) is communicated with the outlet of an external gas supply device. The cover body (1) is also provided with a pressure relief hole (4) on its surface, a pressure relief pipe (5) is fixedly connected to the inner wall of the pressure relief hole (4), and a pressure relief valve (6) is fixedly installed on the pressure relief pipe (5).

2. A manhole cover for a pressurized test chamber according to claim 1, characterized in that: A first control valve (7) is fixedly installed on the outside of the pressurizing pipe (3); the engagement states of the first control valve (7) and the pressure relief valve (6) are opposite; and a linkage component is provided between the valve core operating part of the first control valve (7) and the valve core operating part of the pressure relief valve (6).

3. A manhole cover for a pressurized test chamber according to claim 2, characterized in that: The first control valve (7) and the pressure relief valve (6) are both ball valves, the rotation track plane of the valve core passage in the first control valve (7) is parallel to the rotation track plane of the valve core passage in the pressure relief valve (6), the valve body passages of the first control valve (7) and the pressure relief valve (6) are parallel, and the projection of the valve core operating rod of the first control valve (7) and the axial extension line of the valve core passage in the pressure relief valve (6) on the rotation track plane intersects perpendicularly.

4. A manhole cover for a pressurized test chamber according to claim 3, characterized in that: The valve core operating rod of the first control valve (7) is parallel to the valve core operating rod of the pressure relief valve (6); one side of the valve core operating rod of the first control valve (7) is fixedly connected to a first transmission wheel (8); one side of the valve core operating rod of the pressure relief valve (6) is fixedly connected to a second transmission wheel (9); a transmission member (10) is provided between the first transmission wheel (8) and the second transmission wheel (9); the transmission member (10) is adapted to the first transmission wheel (8) and the second transmission wheel (9); and an operating handle is fixedly connected to the valve core operating rod of the pressure relief valve (6).

5. A manhole cover for a pressurized test chamber according to claim 4, characterized in that: The cover body (1) is provided with a mounting hole on its surface, the transmission member (10) is slidably arranged inside the mounting hole, a protective shell (11) is fixedly installed on the inner wall of the cover body (1), the protective shell (11) coincides with the mounting hole, and the second transmission wheel (9) is located inside the protective shell (11), and a through hole for a valve core operating rod of the pressure relief valve (6) to pass through is provided on the surface of the protective shell (11), and the valve core operating rod of the pressure relief valve (6) passes through the through hole.

6. A manhole cover for a pressurized test chamber according to claim 5, characterized in that: A first air duct (12) is fixedly connected to the inner wall of the filling hole (2); one end of the first air duct (12) is connected to the filling hole (2); and the other end of the first air duct (12) is connected to the first alarm unit (13).

7. A manhole cover for a pressurized test chamber according to claim 6, characterized in that: A second air duct (14) is fixedly connected to the outer wall of the pressure relief hole (4); one end of the second air duct (14) is in communication with the pressure relief hole (4); and the other end of the second air duct (14) is in communication with the second alarm unit (15).

8. A manhole cover for a pressurized test chamber according to claim 7, characterized in that: The pressurizing pipe (3) is also connected to a second control valve (16), the second control valve (16) and the first control valve (7) are connected in series, a first detection hole and a second detection hole are respectively opened on the surface of the cover body (1), and a pressure gauge (17) is fixedly installed on the outer side wall of the first detection hole; A third air guide tube (18) is fixedly connected to the outer wall of the second detection hole, one end of the third air guide tube (18) is in communication with the second detection hole, the other end of the third air guide tube (18) is fixedly connected to a liquid storage tank (19), a liquid guide tube (20) is fixedly connected to the surface of the liquid storage tank (19), the lower end of the liquid guide tube (20) is located inside the liquid storage tank (19), the lower end of the liquid guide tube (20) is located below the liquid level of the liquid storage tank, and the lower end of the air guide tube is located above the liquid level inside the liquid storage tank (19); a third control valve (21) is fixedly mounted on the third air guide tube (18).

9. A manhole cover for a pressurized test chamber according to claim 8, characterized in that: The first alarm unit (13) and the second alarm unit (15) both comprise an air pressure detection module, an information sending module, a control module and a receiver. The air pressure detection modules are respectively fixedly installed inside the pressure relief hole (4) and the filling hole (2). The air pressure detection modules are used to sense the air pressure values ​​inside the pressure relief hole (4) and the filling hole (2).

Images