CN210920232U

CN210920232U - Two-stage pilot-operated nitrogen-sealing nitrogen-releasing fire-retardant integrated valve

Info

Publication number: CN210920232U
Application number: CN201921749278.3U
Authority: CN
Inventors: 钟临风; 邹纯; 钟晓山
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-18
Filing date: 2019-10-18
Publication date: 2020-07-03
Anticipated expiration: 2029-10-18

Abstract

The utility model provides a second grade guide's formula nitrogen seals and leaks integrative valve of nitrogen back-fire relief, with the storage tank nitrogen of trades such as petroleum, chemical industry, pharmacy seal the nitrogen in the system and seal the valve, let out nitrogen valve, spark arrester and carry out the function integration to integrated pressure signal pipe is connected with the storage tank through only interface main valve flange. The integrated valve mainly comprises four parts, namely a secondary pilot valve group, a nitrogen sealing valve end, a nitrogen discharging valve end and a main valve; the two-stage pilot valve group adopts an actuator to respectively control the opening and closing of the nitrogen release valve end and the nitrogen sealing valve end through an upper pilot valve and a lower pilot valve; introducing nitrogen into the storage tank through a nitrogen inlet pipeline at the nitrogen sealing valve end; a fire retardant element is arranged in a valve cavity of the main valve, a pressure difference meter is connected with an upper cavity and a lower cavity to monitor the circulation condition, and a signal pipe is arranged in the lower cavity and is connected to an actuator. The nitrogen sealing set pressure is realized by adjusting an adjusting bolt of the actuator, and the nitrogen leakage set pressure is realized by adjusting the up-down sliding position of the upper pilot valve body on the second-stage pilot valve body, so that the online adjustment, the function integration, the convenient installation and the cost reduction are realized.

Description

Two-stage pilot-operated nitrogen-sealing nitrogen-releasing fire-retardant integrated valve

Technical Field

The utility model belongs to trade liquid safety storage facilities technical neighborhood such as oil, chemical industry, pharmacy relates to a storage tank deck nitrogen seals system's equipment, seals nitrogen, lets out nitrogen, the integrated nitrogen that is as an organic whole of functions such as back-fire relief seals the system control valve.

Background

Many of liquid raw materials, intermediates, products and the like in the industries of petroleum, chemical industry, pharmacy and the like are highly volatile, toxic, flammable and explosive, and a nitrogen sealing system is generally equipped for an atmospheric storage tank used for storing the liquid. The nitrogen sealing system is generally installed on the tank top of the storage tank, and mainly comprises a nitrogen sealing valve, a nitrogen release valve, a breather valve, an emergency release valve, a flame arrester and the like, wherein each device is installed respectively, and a plurality of holes are opened on the tank top generally, so that not only are the leakage points of the storage tank increased, but also more uncertain factors are considered in the design of the storage tank, the stress of the storage tank is more complex, the safety is examined, and the installation, maintenance and overhaul of the device are not facilitated. It would be an advance if the control equipment of the tank top could be optimized and integrated, and the redundancy could be simplified. The utility model discloses seal the valve with nitrogen, let out nitrogen valve, spark arrester and carry out function integration and redesign to the mouth is pressed in the integration, not only makes nitrogen seal control equipment simplify, will have the equipment of these three kinds of functions moreover and the interface of being connected of storage tank reduce only one, is favorable to design, installation, maintenance, the maintenance of whole storage tank system.

Disclosure of Invention

The utility model relates to a two-stage guide's formula nitrogen seals and leaks integrative valve of nitrogen back-fire relief mainly contains second grade guide valves 100, let out nitrogen valve end 200, nitrogen seals valve end 300, main valve 400 four parts, last pilot valve 125 control in the second grade guide valves lets out the valve port of nitrogen valve end 200 and opens and close, lower pilot valve 126 control nitrogen seals the valve port of valve end 300 and opens and close, second grade guide valves 100, let out nitrogen valve end 200, nitrogen seals valve end 300 and all installs on main valve 400, configuration back-fire relief component 404 and get pressure mouth 406 in the main valve 400 inner chamber, 407, integrative valve passes through main valve flange 405 and is connected with the storage tank, see figure 1, 2.

In fig. 2, the two-stage pilot valve group 100 is mainly composed of an actuator 108, an upper pilot valve 125, and a lower pilot valve 126. The nitrogen seal set pressure of the nitrogen seal valve end 300 is adjusted by changing the compression amount of the adjusting spring 109 through the adjusting bolt 110; the nitrogen bleed set pressure of the nitrogen bleed valve port 200 is adjusted by adjusting the up-down sliding position of the upper pilot valve body 114 on the secondary pilot valve body 111. The lower pilot valve 126 is composed of a lower pilot valve body 119, a lower pilot valve rod 120 and a lower pilot valve spring 124, and the nitrogen sealing valve end control interface 121 is connected with the nitrogen sealing end air chamber 303 through a nitrogen sealing end control pipe 105; the actuator valve rod 116 and the lower pilot valve spring 124 act together to control the lower pilot valve rod 120 to move up and down, so that the nitrogen sealing valve end control interface 121 is respectively communicated with or disconnected from the lower pilot valve pressure inlet 122 and the lower pilot valve pressure relief interface 123. The upper pilot valve 125 is composed of an upper pilot valve body 114, a sealing slider 112, a secondary pilot valve body 111, and an actuator valve rod 116. The middle lower part of the actuator valve rod 116 forms an upper pilot valve 125 valve core, and is provided with a step shaft structure and a valve rod air hole 133 for switching the communication between the nitrogen discharge valve end control interface 113 and the upper pilot valve pressure inlet 115 and the upper pilot valve pressure discharge interface 118; the second-stage pilot valve body 111 is provided with a through key groove 127; the sealing slider 112 is a key structure, is installed inside the upper pilot valve body 114, and is commonly provided with a nitrogen bleed valve end control interface 113 which is communicated with the slider air hole 134 and forms sliding fit with the through key groove 127. The sliding of the sealing slider 112 in the through key groove 127 drives the upper pilot valve body 114 to slide up and down on the secondary pilot valve body 111, so that the position of the nitrogen release valve end control interface 113 is changed up and down, thereby changing the pressure release pressure of the nitrogen release valve end (200) and realizing the adjustment of the nitrogen release set pressure of the nitrogen release valve end (200). The actuator 108 respectively controls the nitrogen inlet and nitrogen outlet two-stage pressure of the nitrogen sealing valve end 300 and the nitrogen discharging valve end 200 through the combined action of the actuator valve rod 116, the lower pilot valve 126 and the upper pilot valve 125.

In fig. 2, the inlet pipe 104 introduces the nitrogen 128 from the inlet of the nitrogen-sealed valve end 300 into the upper pilot inlet port 115 and the lower pilot inlet port 122 as a control air source for controlling the opening and closing of the valve ports of the nitrogen-released valve end 200 and the nitrogen-sealed valve end 300. The nitrogen release end control flexible pipe 103 is connected with the nitrogen release valve end control interface 113 and the nitrogen release end air chamber 203, and the air pressure in the air chamber 203 and the acting force of the nitrogen release end spring 202 on the nitrogen release end valve core 204 and the acting force of the storage tank gas on the nitrogen release end valve core 204 jointly act to determine the opening and closing of the valve port of the nitrogen release valve end (the mutual position between the valve cage and the valve seat forms the valve port, such as the mutual position between the nitrogen release end valve cage 205 and the nitrogen release end valve seat 206). The nitrogen sealing end control pipe 105 is connected with a nitrogen sealing valve end control interface 121 and a nitrogen sealing end air chamber 303, and the opening and closing of the nitrogen sealing valve end valve port are determined under the combined action of the air pressure in the air chamber 303, the acting force of the nitrogen sealing end spring 302 on the nitrogen sealing end valve core 304 and the acting force of the inlet nitrogen 128 on the nitrogen sealing end valve core 304. The pressure relief pipe 106 connects the upper pilot valve pressure relief interface 118 and the lower pilot valve pressure relief interface 123 with the nitrogen-terminated lower cavity 308, and the control gas in the nitrogen-terminated gas chamber 203 and the nitrogen-terminated gas chamber 303 is relieved to the nitrogen-terminated lower cavity 308 under the control of the upper pilot valve 125 and the lower pilot valve 126 respectively.

In fig. 1 and 2, a signal pipe 101 takes pressure from a pressure taking port 407 below a lower cavity 403 of a main valve and is led into the lower cavity of an actuator 108, and a pressure gauge 102 is arranged between the signal pipe and the lower cavity of the actuator to display the pressure of a storage tank; and a pressure difference meter 107 is arranged at a pressure taking port 406 on the upper main valve cavity 402, the other end of the pressure difference meter is connected with the signal pipe 101, and the pressure difference between the upper main valve cavity 402 and the lower main valve cavity 403 is displayed so as to monitor the flow condition of the fire retardant element 404. The two-stage pilot type nitrogen sealing, releasing and fire retarding integrated valve is connected with the storage tank through a main valve flange 405; the nitrogen inlet pipeline 309 is connected with the nitrogen sealing end lower cavity 308, is isolated from the main valve upper cavity 402 and the main valve lower cavity 403, introduces nitrogen which is decompressed by the nitrogen sealing valve end 300 and still higher than the pressure of the storage tank into the storage tank, mixes and buffers the nitrogen with gas in the storage tank, avoids impacting the signal pressure of the pressure taking at the lower pressure taking port 407, and enables the signal pressure to accurately and dynamically reflect the pressure of the storage tank. The nitrogen inlet pipe connector 310 is optimally designed according to the parameters of different storage tanks, so that the influence of inlet nitrogen on the signal pressure of the pressure taking at the lower pressure taking port 407 is reduced as much as possible.

Fig. 2, when the tank pressure is between the set pressures of the nitrogen sealing valve end 300 and the nitrogen releasing valve end 200, the tank is in a balanced state, the inlet nitrogen 128 enters the pressure inlet 115 of the upper pilot valve 125 through the pressure inlet pipe 104, exits from the nitrogen releasing valve end control interface 113, enters the nitrogen releasing end air chamber 203 through the nitrogen releasing end control flexible pipe 103, and pushes the valve core 204 together with the nitrogen releasing end spring 202 to close the valve port of the nitrogen releasing valve end 200; meanwhile, the inlet nitrogen 128 enters the pressure inlet 122 of the lower pilot valve 126 through the pressure inlet pipe 104, exits from the nitrogen-sealed valve end control interface 121, enters the nitrogen-sealed air chamber 303 through the nitrogen-sealed control pipe 105, and pushes the valve core 304 to close the valve port of the nitrogen-sealed valve end 300 together with the nitrogen-sealed spring 302.

Referring to fig. 2 and 3, when the pressure of the storage tank drops below the set pressure of the nitrogen sealing valve end 300, the actuator valve rod 116 moves downward along with the pressure reduction of the lower cavity of the actuator 108, the lower pilot valve rod 120 is pushed to move downward, the lower pilot valve pressure inlet 122 is gradually closed, meanwhile, the lower pilot valve pressure relief interface 123 is gradually opened and communicated with the nitrogen sealing valve end control interface 121, the control gas in the nitrogen sealing end gas chamber 303 is gradually relieved to the nitrogen sealing end lower cavity 308, the valve port of the nitrogen sealing valve end 300 is opened, the inlet nitrogen 128 is decompressed through the valve port and enters the inside of the storage tank through the nitrogen inlet pipeline 309, and is buffered and mixed with the internal gas, and the pressure of the storage. Along with the rising of the pressure of the storage tank, the gas pressure entering the lower cavity of the actuator 108 through the signal pipe 101 rises along with the rising, the valve core of the actuator is pushed to move upwards, the valve rod 116 of the actuator moves upwards, the valve rod 120 of the lower pilot valve moves upwards under the action of the spring 124 of the lower pilot valve, the pressure relief interface 123 of the lower pilot valve is gradually closed, meanwhile, the pressure inlet 122 of the lower pilot valve is gradually opened, the inlet nitrogen 128 enters the nitrogen blocking air chamber 303 again, and the valve port is gradually closed under the combined action of the nitrogen blocking spring 302. The pressure of the control gas in the nitrogen-terminated gas chamber 303 is continuously changed in the process of opening the valve port of the nitrogen-terminated valve end 300, from the beginning to be equal to the pressure of the inlet nitrogen 128, when the lower pilot valve rod 120 descends, the lower pilot valve pressure inlet 122 is gradually closed and the pressure relief interface 123 is gradually opened, the gas chamber 303 is simultaneously communicated with the lower pilot valve pressure inlet 122 and the lower pilot valve pressure relief interface 123, and the pressure in the gas chamber 303 is changed along with the size of the communicated sectional area of the two interfaces; along with the descending of the lower pilot valve rod 120, the communication sectional area of the pressure inlet 122 is smaller and smaller, the communication sectional area of the pressure relief interface 123 is larger and larger, and the pressure in the air chamber 303 is smaller and smaller until the pressure inlet 122 is closed, the pressure relief interface 123 is completely opened, the pressure in the air chamber 303 is equal to the pressure in the nitrogen sealing end lower cavity 308, and meanwhile, the valve port of the nitrogen sealing end 300 is gradually opened. Because the cross-sectional areas of the lower pilot pressure relief port 123 and the lower pilot pressure inlet port 122 are small as the control pipeline ports, the pressure change in the nitrogen sealing end air chamber 303 is relatively fast, which means that the opening of the nitrogen sealing valve end 300 is relatively fast, but the nitrogen sealing valve end 300 is opened smoothly without impact. When the tank pressure rises, the pressure in the nitrogen-capped gas chamber 303 gradually increases until it equals the pressure of the inlet nitrogen gas 128, and the valve port of the nitrogen-capped valve end 300 is gradually and smoothly closed.

Referring to fig. 2 and 3, when the pressure of the storage tank rises, the actuator valve rod 116 moves upwards along with the pressure rise of the lower cavity of the actuator 108, the nitrogen discharge valve end control interface 113 of the upper pilot valve 125 is gradually disconnected from the upper pilot valve pressure inlet 115 and gradually communicated with the upper pilot valve pressure discharge interface 118, the control gas in the nitrogen discharge end gas chamber 203 is gradually discharged to the nitrogen sealing end lower cavity 308, the valve port of the nitrogen discharge valve end 200 is gradually opened, and the gas in the storage tank is discharged to the recovery pipeline. Along with the pressure reduction of the storage tank, the gas pressure entering the lower cavity of the actuator 108 through the signal pipe 101 is reduced, the adjusting spring 109 pushes the valve core of the actuator to move downwards, the valve rod 116 of the actuator moves downwards, the control interface 113 of the nitrogen release valve end is gradually disconnected with the pressure release interface 118 of the upper pilot valve and gradually communicated with the pressure inlet 115 of the upper pilot valve, the inlet nitrogen 128 enters the gas chamber 203 of the nitrogen release end again, and the valve port of the nitrogen release valve end 200 is gradually closed under the combined action of the spring 202 of the nitrogen release end. The pressure of the control gas in the gas chamber 203 of the nitrogen bleed end is continuously changed in the process of opening and closing the nitrogen bleed valve end 200, which is realized by the gas groove 131 inside the gas hole of the sealing slider 112, so that the valve port of the nitrogen bleed valve end 200 is smoothly opened and closed. The actuator valve stem 116 also has a downward air groove 132 at the air hole 133 to prevent the actuator valve stem 116 from rising rapidly when the tank pressure rises suddenly, and the valve stem air hole 133 is suddenly higher than the nitrogen release valve end control interface 113, so that the nitrogen release end air chamber 203 cannot release pressure in time to cause the nitrogen release valve end 200 to fail to open.

The sectional area of the nitrogen sealing gas chamber 303 is larger than that of the inlet of the nitrogen sealing valve end 300, and the nitrogen sealing gas chamber and the nitrogen sealing spring 302 jointly act to ensure that the valve port is opened and closed flexibly. The cross section area of the gas chamber 203 at the nitrogen release end is 1/3-1/2 of the nitrogen release pipeline 208, when the pressure release of the gas is controlled, the end of the nitrogen release pipeline 208 has absolute force bearing area advantage, and can push the nitrogen end-capped valve core 204 to release the pressure from the nitrogen release end valve cage 205; when the inlet nitrogen 128 becomes the control gas to enter the nitrogen bleed end chamber 203, the absolute gas pressure advantage (the inlet nitrogen 128 pressure is usually 5 to 12barg) exists at the nitrogen bleed end chamber 203 end, and the valve port of the nitrogen bleed valve end 200 is closed under the combined action of the inlet nitrogen 128 and the nitrogen bleed end spring 202.

The nitrogen sealing system is usually micro-positive pressure, and the pressure regulating range of the two-stage pilot type nitrogen sealing, releasing and fire retarding integrated valve can be set to cover all field applications. The product leaves factory state is that the actuator valve rod 116 is in the lowest position under the action of the adjusting spring 109, and pushes the lower pilot valve rod 120 to be in the lower position of the lower pilot valve 126, and the nitrogen seal valve end control interface 121 is communicated with the lower pilot valve pressure relief interface 123; the nitrogen bleed valve end 200 is closed under the action of the nitrogen bleed end spring 202; the nitrogen sealed valve end 300 is closed by the nitrogen sealed spring 302. After the integrated valve is installed on the tank to connect the pipeline, the inlet nitrogen 128 will push the nitrogen sealing valve end 300 open to enter the tank and enter the nitrogen release end gas chamber 203, as shown in fig. 4.

The two-stage pilot valve group 100 controls two pilot valves by using one actuator, and respectively controls the nitrogen sealing valve end 300 and the nitrogen discharging valve end 200, and the set pressure of the nitrogen discharging end and the set pressure of the nitrogen sealing end can be adjusted on site. When the actuator valve rod 116 moves up and down, a distance is reserved between the position where the lower pilot valve (126) pre-opens the nitrogen sealing valve end (300) and the position where the upper pilot valve (125) pre-opens the nitrogen discharging valve end (200) in a descending mode, the difference between the set pressure of nitrogen sealing and the set pressure of nitrogen discharging is achieved, and the normal stable pressure interval of the storage tank is located between the two set pressures. The adjusting ring 129 with different thicknesses can preset the difference value between the nitrogen seal set pressure adjusting range and the nitrogen leakage set pressure adjusting range according to the actual working condition, then set the accurate nitrogen seal set pressure through the adjusting spring 109, and set the accurate nitrogen leakage set pressure and the locking position of the set screw 117 by adjusting the position between the upper pilot valve body 114 and the secondary pilot valve body 111 up and down. The sliding distance of the seal slider 112 in the through-key groove 127, i.e., the adjustment distance of the upper pilot valve 125, will be set to a large value to cover a wider range of the set pressure of the nitrogen release, thereby reducing the number of the adjustment rings 129, and satisfying the lower limit value covering the set pressure of the nitrogen release in practical use when the adjustment ring 129 is not equipped, the upper limit value will be satisfied by increasing the adjustment ring 129. The two-stage pilot valve group 100, the nitrogen release valve end 200, the nitrogen seal valve end 300 and the main valve 400 in the two-stage pilot type nitrogen sealing nitrogen release fire retardant integrated valve are in modular design, and selection and combination of different sizes can be performed according to different working conditions. The two-stage pilot valve group 100 is used as a control component, and can realize the application of one specification and different configurations of the adjusting spring 109 and the adjusting ring 129 which meet all pressure ranges of the nitrogen sealing system.

The adjusting springs 109 and the adjusting rings 129 are designed into a series, and the nitrogen seal set pressure range of each spring, the nitrogen leakage set pressure range corresponding to the adjusting ring 129 without increasing, and the nitrogen leakage set pressure range corresponding to the adjusting ring 129 with increasing different thicknesses are arranged into a table according to tests and calculation, so that the model selection is convenient. When the nitrogen sealing valve end 300 is installed, the nitrogen sealing valve end can horizontally rotate by 90 degrees or-90 degrees, so that the flange of the nitrogen sealing valve end and the flange of the nitrogen leakage valve end 200 are in the same direction or opposite directions by 180 degrees to meet the field requirement.

Fire-retardant component 404 is installed in main valve 400 inner chamber, and its sectional area is greater than the sectional area of letting out nitrogen passageway 208 far away to there is the space can set up sufficient thickness, and its heat radiating area is big, and the circulation ability is strong, can satisfy to let out nitrogen valve end 200 pressure release with the high efficiency, and does not influence down and get pressure port 407 department signal pressure, can effectively prevent open flame to get into the storage tank again, effectively protects storage tank safety. The pressure difference meter 107 displays the pressure difference between the upper main valve cavity 402 and the lower main valve cavity 403, so that the flow condition of the fire retardant element 404 is effectively monitored, and the condition that the fire retardant element is blocked and cannot be found in time is avoided. The pressure difference meter 107 can also be replaced by a pressure difference transmitter to realize remote monitoring and alarming of a control room.

Drawings

Fig. 1 is an appearance view of a two-stage pilot-operated nitrogen-sealing nitrogen-releasing fire-retardant integrated valve.

Fig. 2 is a cross-sectional view of the integrated valve with the nitrogen sealing valve end 300 and the nitrogen release valve end 200 closed.

Fig. 3 is a schematic structural diagram of two-stage pilot valve set 100 in different control states.

Fig. 4 is a cross-sectional view of the integrated valve with the nitrogen sealing valve end 300 open and the nitrogen release valve end 200 closed.

Fig. 5 is a cross-sectional view of the integrated valve with the nitrogen sealing valve end 300 closed and the nitrogen release valve end 200 open.

The codes in the figure are respectively: 100-a two-stage pilot valve group; 101-a signal tube; 102-pressure gauge; 103-nitrogen discharge end control flexible tube; 104-a pressure inlet pipe; 105-nitrogen capped control tubes; 106-pressure relief pipe; 107-differential pressure gauge; 108-an actuator; 109-adjusting the spring; 110-adjusting bolt; 111-a secondary pilot valve body; 112-sealing slide block; 113-nitrogen release valve end control interface; 114-an upper pilot valve body; 115-upper pilot valve pressure inlet; 116-an actuator valve stem; 117-set screw; 118-an upper pilot pressure relief interface; 119-lower pilot valve body; 120-lower pilot valve stem; a 121-nitrogen seal valve end control interface; 122-lower pilot inlet pressure port; 123-lower pilot valve pressure relief interface; 124-lower pilot valve spring; 125-an upper pilot valve; 126-lower pilot valve; 127-through keyway; 128-inlet nitrogen; 129-adjusting ring; 130-pressure relief gas; 131-slider air slot; 132-valve stem gas groove; 133-valve stem vent; 134-slider air holes; 200-a nitrogen bleed valve end; 201-nitrogen bleed end valve body; 202-a nitrogen bleed end spring; 203-nitrogen bleed end gas chamber; 204-a nitrogen bleed end valve core; 205-nitrogen bleed end cage; 206-bleed nitrogen end valve seat; 207-nitrogen bleed end flange; 208-nitrogen discharge pipeline; 300-nitrogen seal valve end; 301-nitrogen-capped valve bodies; 302-nitrogen terminated springs; 303-nitrogen end-capped gas chamber; 304-nitrogen-capped valve cartridges; 305-nitrogen-capped valve seats; 306-a nitrogen end-sealing flange; 307-nitrogen-terminated valve cages; 308-nitrogen sealed lower cavity; 309-nitrogen inlet pipeline; 310-nitrogen inlet pipe joint; 400-a main valve; 401-main valve body; 402-a main valve upper chamber; 403-lower main valve cavity; 404-a flame retardant element; 405-a main valve flange; 406-upper pressure tapping; 407-lower pressure tapping.

Detailed Description

And selecting a proper adjusting spring 109 according to the nitrogen seal set pressure (or set pressure range) required by the nitrogen seal system, selecting a proper adjusting ring 129 according to the nitrogen leakage set pressure (or set pressure range) or not, and assembling the two-stage pilot valve group 100. And selecting a proper nitrogen sealing valve end 300 and a proper nitrogen releasing valve end 200 according to the flow requirements of nitrogen inlet and nitrogen release, selecting a proper main valve 400 and a fire retardant element 404, and assembling the main valve and the fire retardant element together with the secondary pilot valve group 100 to form a finished product, namely, a secondary pilot type nitrogen sealing and nitrogen releasing fire retardant integrated valve.

Pre-adjusting according to the set pressure of the nitrogen seal and the set pressure of the nitrogen leakage, installing the nitrogen seal and the set pressure of the nitrogen leakage on a simulation storage tank debugging device of a manufacturer for fine adjustment, and then installing the nitrogen seal and the nitrogen leakage on a field storage tank to debug equipment to be qualified.

The tank equilibrium state is operating with an internal pressure between the nitrogen seal set pressure and the nitrogen bleed set pressure. When the external environment temperature drops or (and) the liquid pump-out level in the storage tank drops, the mixed pressure of the nitrogen above the storage tank and the evaporation gas is reduced, and a pressure signal is transmitted to the lower cavity of the actuator 108 through the signal pipe 101. When the pressure is lower than the set pressure of the nitrogen sealing valve end 300, the actuator valve rod 116 moves downward along with the pressure reduction of the lower cavity of the actuator 108, the lower pilot valve rod 120 is pushed to move downward, the lower pilot valve pressure inlet 122 is gradually closed, meanwhile, the lower pilot valve pressure relief interface 123 is gradually opened and communicated with the nitrogen sealing valve end control interface 121, the control gas in the nitrogen sealing end gas chamber 303 is gradually relieved to the nitrogen sealing end lower cavity 308, the valve port of the nitrogen sealing valve end 300 is gradually opened, the inlet nitrogen 128 is decompressed through the valve port and enters the inside of the storage tank through the nitrogen inlet pipeline 309, and is buffered and mixed with the internal gas, and the pressure of the storage tank gradually rises, as shown. Along with the rising of the pressure of the storage tank, the gas pressure entering the lower cavity of the actuator 108 through the signal pipe 101 rises along with the rising, the valve core of the actuator is pushed to move upwards, the valve rod 116 of the actuator moves upwards, the valve rod 120 of the lower pilot valve moves upwards under the action of the spring 124 of the lower pilot valve, the pressure relief interface 123 of the lower pilot valve is gradually closed, meanwhile, the pressure inlet 122 of the lower pilot valve is gradually opened, the inlet nitrogen 128 enters the nitrogen end sealing gas chamber 303 again, and the valve port is gradually closed under the combined action of the nitrogen end sealing spring 302. The pressure of the control gas in the nitrogen sealing gas chamber 303 is continuously changed in the opening and closing processes of the valve port of the nitrogen sealing valve end 300, so that the valve port of the nitrogen sealing valve end 300 is smoothly opened and closed. The tank is thus again in equilibrium after a loss of pressure, see fig. 2.

When the temperature of the external environment rises or (and) the liquid pumping level in the storage tank rises, the mixed pressure of the nitrogen above the storage tank and the evaporated gas rises, and a pressure signal is transmitted to the lower cavity of the actuator 108 by the signal pipe 101. When the pressure is higher than the set pressure of the nitrogen release valve end 200, the actuator valve rod 116 moves upward along with the pressure increase of the lower cavity of the actuator 108, the nitrogen release valve end control interface 113 of the upper pilot valve 125 is gradually disconnected from the upper pilot valve pressure inlet 115 and gradually communicated with the upper pilot valve pressure release interface 118, the control gas in the nitrogen release end gas chamber 203 is gradually released to the nitrogen sealing end lower cavity 308, the valve port of the nitrogen release valve end 200 is gradually opened, and the gas in the storage tank is released to the recovery pipeline, as shown in fig. 5. Along with the pressure reduction of the storage tank, the pressure of the gas entering the lower cavity of the actuator 100 through the signal pipe 101 is reduced, the adjusting spring 109 pushes the valve core of the actuator to move downwards, the valve rod 116 of the actuator moves downwards, the control interface 113 of the nitrogen release valve end is gradually disconnected with the pressure relief interface 118 of the upper pilot valve and is gradually communicated with the pressure inlet 115 of the upper pilot valve, the inlet nitrogen 128 enters the gas chamber 203 of the nitrogen release end again, and the valve port of the nitrogen release valve end 200 is gradually closed under the combined action of the spring 202 of the nitrogen release end. The pressure of the control gas in the gas chamber 203 of the nitrogen bleed end is continuously changed in the opening and closing processes of the valve port of the nitrogen bleed valve end 200, so that the valve port of the nitrogen bleed valve end 200 is smoothly opened and closed. The tank is then again in equilibrium after an overpressure, see fig. 2.

Claims

1. A two-stage pilot-operated nitrogen-sealing nitrogen-releasing fire-retardant integrated valve mainly comprises four parts, namely a two-stage pilot valve group (100), a nitrogen-releasing valve end (200), a nitrogen-sealing valve end (300) and a main valve (400); the method is characterized in that: the two-stage pilot valve group (100) adopts an actuator (108) to respectively control the opening and closing of a nitrogen discharge valve end (200) and a nitrogen sealing valve end (300) through an upper pilot valve (125) and a lower pilot valve (126); the inlet nitrogen (128) at the nitrogen sealing valve end (300) is introduced into the upper pilot valve pressure inlet (115) and the lower pilot valve pressure inlet (122) by the pressure inlet pipe (104) to be used as control gas for controlling the opening and closing of the valve ports of the nitrogen releasing valve end (200) and the nitrogen sealing valve end (300); the upper pilot valve pressure relief interface (118) and the lower pilot valve pressure relief interface (123) are connected with the nitrogen-terminated lower cavity (308) through the pressure relief pipe (106); under the control of the upper pilot valve (125) and the lower pilot valve (126), respectively injecting control gas into the nitrogen-venting end gas chamber (203) and the nitrogen-sealing end gas chamber (303) or respectively releasing the control gas in the nitrogen-venting end gas chamber (203) and the nitrogen-sealing end gas chamber (303) to the nitrogen-sealing end lower cavity (308) through the nitrogen-venting valve end control interface (113) and the nitrogen-sealing valve end control interface (121); the nitrogen sealing set pressure is realized by adjusting an adjusting bolt (110) of an actuator, and the nitrogen leakage set pressure is realized by adjusting the up-down sliding position of an upper pilot valve body (114) on a secondary pilot valve body (111), so that online adjustment is realized; the nitrogen sealing valve end (300) introduces nitrogen which is decompressed and still higher than the pressure of the storage tank into the storage tank through a nitrogen inlet pipeline (309) which is isolated from a main valve upper cavity (402) and a main valve lower cavity (403), and the nitrogen is mixed and buffered with gas in the tank, so that the signal pressure of the pressure at a lower pressure taking port (407) is prevented from generating impact, and the signal pressure can accurately and dynamically reflect the pressure of the storage tank; a fire retardant element (404) is arranged in the main valve cavity, and a pressure difference meter (107) is connected with the main valve upper cavity (402) and the main valve lower cavity (403) to monitor the flow condition of the fire retardant element (404); a pressure signal pipe (101) and a pressure gauge (102) are arranged in a lower cavity of a main valve through a lower pressure taking port (407) to an actuator (108) so as to feed back the pressure of the storage tank; the nitrogen release valve end (200) is decompressed through the upper cavity (402) of the main valve; the two-stage pilot valve group (100), the nitrogen release valve end (200) and the nitrogen sealing valve end (300) are installed on a main valve (400) and are connected with the storage tank through a single-interface main valve flange (405).

2. The two-stage pilot-operated nitrogen-sealing nitrogen-discharging fire-retardant integrated valve as claimed in claim 1, wherein: the upper pilot valve (125) is composed of an upper pilot valve body (114), a sealing slide block (112), a secondary pilot valve body (111) and an actuator valve rod (116); the middle lower part of the actuator valve rod (116) forms an upper pilot valve (125) valve core, and a step shaft structure and a valve rod air hole (133) are arranged for switching the communication between a nitrogen release valve end control interface (113) and an upper pilot valve pressure inlet (115) and an upper pilot valve pressure release interface (118); a through key groove (127) is formed in the valve body (111) of the secondary pilot valve; the sealing slider (112) is of a key structure, is arranged in the upper pilot valve body (114), is jointly provided with a nitrogen discharge valve end control interface (113) to be communicated with the slider air hole (134), and is in sliding fit with the through key groove (127); the sliding of the sealing slide block (112) in the through key groove (127) drives the upper pilot valve body (114) to slide up and down on the secondary pilot valve body (111), so that the position of the control interface (113) of the nitrogen release valve end is changed up and down, the pressure release pressure of the nitrogen release valve end (200) is changed, and the adjustment of the nitrogen release set pressure of the nitrogen release valve end (200) is realized; the nitrogen discharge valve end control interface (113) is connected with the nitrogen discharge end air chamber (203) by adopting a control flexible pipe (103), thereby realizing the online adjustment of the nitrogen discharge set pressure.

3. The two-stage pilot-operated nitrogen-sealing nitrogen-discharging fire-retardant integrated valve as claimed in claim 1, wherein: in the structure of the upper pilot valve (125), an actuator valve rod (116) moves up and down along with the pressure change of the storage tank, so that a control interface (113) at the nitrogen release valve end is respectively communicated or disconnected with an upper pilot valve pressure inlet (115) and an upper pilot valve pressure release interface (118); the connection and disconnection processes are gradual, one of the two is gradually disconnected while the other is gradually connected, in the process, the control interface (113) of the nitrogen release valve end is simultaneously connected with the upper pilot valve pressure inlet (115) and the upper pilot valve pressure release interface (118), and the pressure of control gas in the gas chamber (203) of the nitrogen release end is changed along with the gradual change of the connection sectional areas of the upper pilot valve pressure inlet (115) and the upper pilot valve pressure release interface (118) until the complete switching is realized; therefore, the opening and closing of the nitrogen discharge valve end (200) under the combined action of the control gas pressure, the nitrogen discharge end spring (202) and the storage tank gas pressure are gradual and stable without impact; a downward air groove (131) is formed in the inner side of the sealing slide block air hole (134) to control and realize the stable opening and closing process; the air hole (133) of the actuator valve rod (116) is also provided with a downward air groove (132) to avoid that when the pressure of the storage tank rises suddenly, the actuator valve rod (116) rises quickly, and the valve rod air hole (133) is suddenly higher than the nitrogen release valve end control interface (113), so that the nitrogen release end air chamber (203) cannot release pressure in time to cause the opening failure of the nitrogen release valve end (200).

4. The two-stage pilot-operated nitrogen-sealing nitrogen-discharging fire-retardant integrated valve as claimed in claim 1, wherein: the lower pilot valve (126) is composed of a lower pilot valve body (119), a lower pilot valve rod (120) and a lower pilot valve spring (124), and a nitrogen sealing valve end control interface (121) is connected with a nitrogen sealing end air chamber (303) through a nitrogen sealing end control pipe (105); the actuator valve rod (116) moves up and down along with the pressure change of the storage tank and controls the lower pilot valve rod (120) to move up and down under the coaction of a lower pilot valve spring (124), so that a nitrogen-sealed valve end control interface (121) is respectively communicated or disconnected with a lower pilot valve pressure inlet (122) and a lower pilot valve pressure relief interface (123); the connection and disconnection processes are gradual, one of the two is gradually disconnected while the other is gradually connected, in the process, the nitrogen sealing valve end control interface (121) is simultaneously connected with the lower pilot valve pressure inlet port (122) and the lower pilot valve pressure relief interface (123), and the pressure of control gas in the nitrogen sealing end air chamber (303) is changed along with the gradual change of the connection sectional areas of the lower pilot valve pressure inlet port (122) and the lower pilot valve pressure relief interface (123) until the connection and the disconnection processes are completely switched; therefore, the opening and closing of the nitrogen sealing valve end (300) under the combined action of the control gas pressure, the nitrogen sealing spring (302) and the inlet nitrogen gas (128) are gradual and smooth without impact.

5. The two-stage pilot-operated nitrogen-sealing nitrogen-discharging fire-retardant integrated valve as claimed in claim 1, wherein: in the process that the actuator valve rod (116) moves up and down along with the pressure change of the storage tank, a distance is reserved between the position of a valve end (300) for pre-opening the nitrogen seal through the lower pilot valve (126) in the descending way and the position of a valve end (200) for pre-opening the nitrogen discharge through the upper pilot valve (125) in the ascending way, the distance realizes the difference between the set pressure of the nitrogen seal and the set pressure of the nitrogen discharge, and the normal stable pressure interval of the storage tank is between the two set pressures; the distance is adjusted by sliding the upper pilot valve body (114) on the secondary pilot valve body (111), and is designed to cover the lower limit value of the pressure difference between the normal nitrogen seal set pressure and the nitrogen discharge set pressure; when the pressure difference between the nitrogen seal set pressure and the nitrogen leakage set pressure exceeds the upper limit value of the normal range, the distance is changed by adding the adjusting ring (129).