CN214535696U

CN214535696U - System for controlling gas passage for LPG double-steel tank

Info

Publication number: CN214535696U
Application number: CN202120408187.4U
Authority: CN
Inventors: 杜恒谦
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-02-24
Filing date: 2021-02-24
Publication date: 2021-10-29
Anticipated expiration: 2031-02-24

Abstract

A system for controlling an air passage for an LPG double-steel tank relates to the technical field of gas supply. The utility model relates to a gas equipment need flame-out the problem of waiting when solving and changing the LPG steel bottle. A system of two steel jar gas circuit of control LPG, include: the system comprises two electromagnetic valves, a pressure sensor and a server; the utility model provides a system of two steel jar gas circuit of control LPG has solved the problem that gas equipment need flame-out to wait when changing the LPG steel bottle through the seamless switching to main gas bottle and reserve gas bottle. The method is mainly used for places such as restaurants or large-scale factories.

Description

System for controlling gas passage for LPG double-steel tank

Technical Field

The utility model belongs to the technical field of the gas is supplied with, in particular to system for gas circuit is connected to control steel jar.

Background

LPG, also known as LPG, has as its main components propane and butane, with small amounts of olefins. LPG is stored in a storage tank vessel in a liquid state at a suitable pressure.

Liquefied petroleum gas is often used as fuel, when the liquefied petroleum gas in the supply equipment is used up, the supply equipment needs to be replaced, and when the supply equipment is replaced, the gas equipment needs to be flamed out for waiting, so that fire needs to be stopped, and the working efficiency of a gas using place is greatly influenced.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to change gas appliances when supply apparatus the problem that the flame-out was waited for. A system for controlling the gas passage for LPG tankers is now provided to solve the above problems.

A system for controlling an air passage for an LPG tanlc, comprising: the system comprises two electromagnetic valves, a pressure sensor and a server; two solenoid valves set up respectively on the passageway between two LPG steel tanks and gas appliances, pressure sensor is used for gathering the pressure of the inside gas of present use steel bottle, pressure sensor 8's pressure signal output part connects the pressure signal input part of server, the storage battery signal input part of two solenoid valves is connected respectively to two level signal output parts of server, the inside minimum pressure warning value that is equipped with of server, the server includes comparison module, comparison module is used for comparing pressure signal and minimum pressure warning value, when pressure signal is less than minimum pressure warning value, the server sends low level signal to the solenoid valve of opening and makes it close, send high level signal to the solenoid valve of closing again simultaneously and make it open.

Preferably, the method further comprises the following steps: the first relay, the second relay, the third relay, the vaporizer power supply and the air source change-over switch; the first relay comprises a first relay coil and a first relay switch, the second relay comprises a second relay coil and a second relay switch, and the third relay comprises a third relay coil and a third relay switch; the first relay switch, the second relay switch and the third relay switch are respectively provided with a first contact, a second contact, a third contact and a fourth contact; the first contact and the fourth contact are same-end contacts, the second contact and the third contact are same-end contacts, the first contact and the second contact are different-end contacts, and the third contact and the fourth contact are different-end contacts; the high level signal output end of the server is respectively connected with a fourth contact of the first relay switch, a fourth contact of the second relay coil, a fourth contact of the third relay switch and a public end of the air source change-over switch, a third contact of the first relay switch is connected with one end of the electromagnetic valve A, a third contact of the second relay coil is connected with one end of the electromagnetic valve B, a third contact of the third relay coil is connected with a negative electrode of the vaporizer power supply, two free ends of the air source change-over switch are respectively connected with one end of the first relay coil and one end of the second relay coil, and the low level signal output end of the server is respectively connected with the other end of the first relay coil, the other end of the second relay coil, the first contact of the first relay switch, the first contact of the second relay coil and the first contact of the third relay.

Preferably, the temperature control digital display module further comprises a display and a temperature sensor, the temperature sensor is used for collecting the temperature inside the vaporizer, the temperature signal output end of the server is connected with the temperature signal input end of the temperature control digital display module, a high-temperature warning value is arranged inside the server, when the temperature signal received by the server is higher than the high-temperature warning value, the server 3 sends a temperature signal to the temperature control digital display module, one end of the third relay coil is connected with the temperature signal input end of the temperature control digital display module, and the other end of the third relay coil is connected with the second output end of the temperature control digital display module.

Preferably, the method further comprises the following steps: further comprising: the device comprises an alternating current power supply and an alternating current switch, wherein the alternating current switch is provided with a first contact, a second contact, a third contact and a fourth contact; the zero line end of the alternating current power supply is connected with the second contact of the alternating current switch, the third contact of the alternating current switch is connected with the low level signal input end of the server, the fire line end of the alternating current power supply is connected with the first contact of the alternating current switch, and the fourth contact of the alternating current switch is connected with the level signal output end of the server.

Preferably, the method further comprises the following steps: the system comprises a power supply indicator lamp, a vaporizer heat preservation indicator lamp, a vaporizer heating indicator lamp, a low-pressure acousto-optic alarm lamp, a high-pressure acousto-optic alarm lamp, an A air source working indicator lamp and a B air source working indicator lamp;

one end of the power supply indicator lamp is connected with the end of the alternating current switch, the other end of the power supply indicator lamp is connected with the end of the alternating current switch, one end of the vaporizer heat preservation indicator lamp is connected with the low level signal input end of the server, the other end of the vaporizer heat preservation indicator lamp is connected with the first output end of the temperature control digital display module, one end of the vaporizer heating indicator lamp is connected with the low level signal input end of the server, the other end of the vaporizer heat preservation indicator lamp is connected with the second output end of the temperature control digital display module, one end of the low-voltage acousto-optic alarm lamp is connected with the pressure signal input end of the pressure sensor, the other end of the low-voltage acousto-optic alarm lamp is connected with the first output end of the pressure sensor, one end of the high-voltage acousto-optic alarm lamp is connected with the second output end of the pressure sensor, one end of the A gas source work indicator lamp is connected with one end of the first relay coil, the other end of the A air source work indicating lamp is connected with the other end of the first relay coil, one end of the B air source work indicating lamp is connected with one end of the second relay coil, and the other end of the B air source work indicating lamp is connected with the other end of the second relay coil.

A system of two steel jar gas circuit of control LPG adopts one to open one and is equipped with of double-circuit air supply passageway, adopts and merges after the explosion-proof solenoid valve of normal close switching control to supply with the gas to the vaporizer all the way, implements a key switching when consuming 99.9% with gas source gas, ensures that continuous air feed is incessant. The continuity, the stability of guaranteeing that the enterprise uses gas production process, improve production efficiency, guarantee product quality effect is outstanding, and the effectual gas equipment that has solved when changing the steel bottle needs to put out fire and wait for, causes the problem that needs to pause with fire.

Drawings

FIG. 1 is a schematic block diagram of a system for controlling gas access to an LPG duplex steel tank;

FIG. 2 is an electrical schematic of a system for controlling the gas path for an LPG duplex steel tank;

fig. 3 is a connection structure diagram of the pressure transmitter.

Detailed Description

The following detailed description will be made with reference to the accompanying drawings and examples, so as to solve the technical problems by applying technical means to the present invention, and to fully understand and implement the technical effects of the present invention. It should be noted that, as long as no conflict is formed, the embodiments and the features in the embodiments of the present invention may be combined with each other, and the technical solutions formed are all within the scope of the present invention.

The first embodiment is as follows: the present embodiment will be described below with reference to fig. 1, and the system for controlling an LPG double tank gas passage according to the present embodiment includes: two electromagnetic valves, a pressure sensor 8 and a server 3; two solenoid valves set up respectively on the passageway between two LPG steel tanks and gas appliances, pressure sensor 8 is used for gathering the pressure of the inside gas of present use steel bottle, pressure sensor 8's pressure signal output part connects server 3's pressure signal input part, server 3's two level signal output parts connect the storage battery signal input part of two solenoid valves respectively, server 3 is inside to be equipped with minimum pressure warning value, server 3 includes comparison module, comparison module is used for comparing pressure signal and minimum pressure warning value, when pressure signal is less than minimum pressure warning value, server 3 sends low level signal to the solenoid valve of opening and makes it close, send high level signal to the solenoid valve of closing again simultaneously and make it open.

The working principle is that the air inlet end of the pipeline is simultaneously connected with two propane steel cylinder liquid phase valves through the two-way air source explosion-proof electromagnetic valve control, the two-way air source explosion-proof electromagnetic valve control is in an one-open one-standby air supply mode, and the output end of the pipeline is combined into one through the two-way A, B air source explosion-proof electromagnetic valve control and is connected with the inlet end of the vaporizing device; the vaporizing device vaporizes the liquid propane into a gaseous medium through heat exchange according to a preset temperature; regulating the gas pressure to 0.18-0.2MP by a first-stage pressure reducing device, and sending the gaseous propane to a gas-liquid separator device through a pipeline; the gas-liquid separator device is a buffer station and a cooling chamber through which the vaporized fuel gas passes, if secondary condensed components are settled, workers can regularly remove residues from the gas-liquid separator device if the secondary condensed components are separated from the gaseous fuel gas, and the gaseous fuel gas is conveyed to each gas device along a connecting pipeline for use; the central control cabinet is divided into an intelligent clock-controlled power supply, a constant-temperature digital display control vaporizer, an intelligent pressure monitoring alarm and an air source explosion-proof electric control switching air source; the intelligent clock-controlled power supply can be automatically started and stopped for 16 time periods according to the work and rest time, so that careless manual operation is avoided, unnecessary power consumption can be effectively reduced, and operability is provided for freezing prevention in winter; the temperature control digital display unit is a digital display temperature control module of the vaporizing device, the vaporizing device is a water bath type vaporizer, the water tank is provided with a temperature sensor for transmitting water temperature information to the temperature control module, and the temperature control module controls the power supply of the vaporizing device to be started and stopped, so that the water temperature is ensured to be constant; the pressure intelligent control monitoring unit receives sensing information of the pressure transmitter;

the intelligent control system for propane vaporization is a standard commercial gas supply system which takes a vaporizer as core equipment and is provided with complete frameworks such as an intelligent clock control, digital display temperature control, pressure intelligent monitoring alarm and switching, and can completely realize two necessary conditions of high-utility pure bottled gas without residue and continuous gas supply.

In the embodiment, the liquid phase vaporization flow is multiplied, so that the requirement of simultaneously using gas for large-scale equipment or multiple equipment is met; the gas is reduced in pressure in stages, so that all equipment can run simultaneously, the phenomenon of fire fight does not exist, and the operation is stable and efficient; the pressure monitoring module prompts gas source switching when the low-pressure alarm gas consumption is set to be 99.9%, and switching to a standby gas source is performed by one key, so that continuous and uninterrupted gas supply is realized; the multipoint gas leakage monitoring alarm is realized, the gas source is cut off in an emergency by one key, and the gas using safety is guaranteed. The central control cabinet is arranged on a production site, so that the operation condition of the equipment and the operation of switching by one key or cutting off the air source in an emergency can be conveniently mastered in real time.

As shown in fig. 3, the a gas source inlet 31 is connected to one end of a first stop valve 32, the other end of the first stop valve 32 is connected to one end of a first pressure gauge 33 and one end of a first explosion-proof solenoid valve 34, the other end of the first explosion-proof solenoid valve 34 is connected to one end of a first check valve 35, the other end of the first check valve 35 is connected to one end of a second stop valve 36, the other end of the second stop valve 36 is connected to one end of a pressure transmitter 43 and one end of a third stop valve 44, respectively, the B gas source inlet 37 is connected to one end of a third stop valve 38, the other end of the third stop valve 38 is connected to one end of a second pressure gauge 39 and one end of a second explosion-proof solenoid valve 40, the other end of the second explosion-proof solenoid valve 40 is connected to one end of a second check valve 41, the other end of the second check valve 41 is connected to one end of a fourth stop valve 42, the other end of the fourth stop valve 42 is connected to one end of a pressure transmitter 43 and one end of a third stop valve 44, the other end of the third shut-off valve 44 is connected to an input of a carburetor 45, and an output of the carburetor 45 is connected to a safety valve 46 and a temperature sensor 47, respectively. The pressure transmitter 43 is used to send a pressure signal to the pressure sensor.

The propane gas-saving combustion furnace has the beneficial effects that the heat value of propane is high, the propane gas-saving combustion furnace can be completely combusted without residue, the gas is saved for over three times, continuous gas supply is uninterrupted, safety, environment friendliness and high efficiency are realized, the flame temperature during combustion is high, the automation degree of time control and temperature control is high, the energy-saving effect is good, the design of a winter anti-freezing function is realized, pressure monitoring and analysis are realized, and the gas source is switched by one key, so that the continuous gas supply is uninterrupted; the installation cost is low, the installation cost is only equal to 10% of that of a natural gas pipeline with equal flow, grading pressure regulation is realized, and when a plurality of devices are shared, the phenomenon of fire fight is avoided, so that the installation is stable and efficient; multi-point computer monitoring, gas leakage alarm, and safe gas utilization control. Meanwhile, by adopting the device, continuous gas supply can be realized, the continuity and the stability of production are guaranteed, a solid foundation is laid for improving the production efficiency and the product quality, too many gas steel cylinders are not required to be stored, the occupied space of gas equipment is saved for users, the phenomenon of illegally storing the steel cylinders is avoided, the potential safety hazard is reduced, and the safety risk is reduced. This patent air supply system installation cost is low, uses the sexual valence relative altitude. The equipment with proper flow is selected and matched according to the gas consumption of the user, so that a capacity increasing room is left for meeting the requirement, and the equipment cost is controlled. The cost of installing a set of gas supply equipment can be recovered by only saving gas and improving the benefit brought by the production efficiency by 6-12 months; the gas supply system realizes modular production, is flexible to install, short in construction period and small in occupied space, and creates a safe, stable, efficient and energy-saving continuous gas supply system for users; the calorific value of the propane liquefied petroleum gas is obviously higher than that of methane natural gas, and the flame temperature is better, so that the function of propane is irreplaceable in some fields; the gas supply system is widely applicable to regions, and users with gas consumption requirements, whether in cities or villages, and whether in hills or seaports, can use the propane gas efficiently in places where the propane can be sent; this gas supply system uses the trade wide range, includes: industrial production, scientific research trials, food processing, washing services, heating services, regional gas supply, and the like.

The second embodiment is as follows: in this embodiment, a system for controlling an air passage for an LPG double steel tank according to the first embodiment is further described, and the system further includes: a first relay, a second relay, a third relay, a vaporizer power supply and an air source change-over switch 11; the first relay comprises a first relay coil 12 and a first relay switch 17, the second relay comprises a second relay coil and a second relay switch 18, and the third relay comprises a third relay coil and a third relay switch 19; the first relay switch 17, the second relay switch 18 and the third relay switch 19 are all provided with a first contact, a second contact, a third contact and a fourth contact; the first contact and the fourth contact are same-end contacts, the second contact and the third contact are same-end contacts, the first contact and the second contact are different-end contacts, and the third contact and the fourth contact are different-end contacts; the level signal output end of the server 3 is respectively connected with the fourth contact of the first relay switch 17, the fourth contact of the second relay coil 18, the fourth contact of the third relay switch 19 and the common end of the gas source change-over switch 11, a third contact of the first relay switch 17 is connected with one end of the electromagnetic valve A, a third contact of the second relay coil 18 is connected with one end of the electromagnetic valve B, a third contact of the third relay coil 19 is connected with the negative electrode of the vaporizer power supply, two free ends of the gas source change-over switch 11 are respectively connected with one end of the first relay coil and one end of the second relay coil, the low level signal output end of the server 3 is connected with the other end of the first relay coil, the other end of the second relay coil, the first contact of the first relay switch 17, the first contact of the second relay coil 18 and the first contact of the third relay 19 respectively.

In the embodiment, a pressure transmitter is arranged at the access end of the vaporizer, the pressure change of an in-use gas source is sensed at all times, when the pressure of the gas source is sensed to be reduced to a preset value, the gas utilization rate of the gas source reaches 99.85 percent, and a gas source pressure monitoring module sends out an audible and visual alarm, at the moment, a field worker immediately rotates a change-over switch, opens a standby gas source and immediately recovers the gas pressure, the alarm is stopped, and the gas supply is recovered to be normal; the air source switching unit consists of a three-gear switch and two green indicating lamps, the switch is arranged in the middle, the indicating lamps are divided into two sides, the switch is set to be A/off/B, the A lamp is on when the switch points to the A air source, and the A air source supplies air; when the switch points to the gas source B, the lamp B is on, and the gas source B supplies gas; when the switch points to 'off', the air source is closed, which is equivalent to cutting off the air source in emergency stop. Pressure 0.8MP constant: total gas amount: 50kg, specific gravity of fuel gas: 2.36kg/m3, cylinder volume: 0.12566m3, gas gaseous volume 21.18644, cylinder volume/gas gaseous volume of 0.0059, and when the pressure drop 1/4 reaches 0.2MP, the gas amount is about 0.0015.

The third concrete implementation mode: the embodiment further describes a system for controlling an air passage for an LPG double steel tank, as shown in fig. 2, the system further includes a temperature control digital display module 4, the temperature control digital display module 4 includes a display and a temperature sensor, the temperature sensor is used for collecting the internal temperature of the vaporizer, a temperature signal output end of the server 3 is connected to a temperature signal input end of the temperature control digital display module 4, a high temperature alarm value is arranged inside the server 3, when the temperature signal received by the server 3 is higher than the high temperature alarm value, the server 3 sends a temperature signal to the temperature control digital display module 4, one end of the third relay coil is connected to the temperature signal input end of the temperature control digital display module 4, and the other end of the third relay coil is connected to a second output end 4-2 of the temperature control digital display module 4.

Aiming at different demands of users in different industries on gas supply, equipment is put in a targeted manner. For example, the demand for gas-fired hot water boilers for heating is: the boiler is guaranteed to be normally started to supply heat on time, and the heating effect can be achieved only when the heating temperature standard is met. Under the condition, the investment cost of equipment is saved for customers, a set of vaporizer device and an intelligent clock-controlled constant-temperature digital display control box are used, the start-stop time can be set in cooperation with the start-stop time of the boiler, and high-degree automation can be realized. The boiler stops firing and the steel cylinder is replaced without influencing heating. And a pressure monitoring and switching device is not needed, so that equipment investment is reduced, and cost is reduced. For example, the gas appliances in the central kitchen are many, and the functions are different, the respective placement positions are different and are scattered, so that a complete set of the gas supply system of the invention is required to be installed to support the efficient and necessary operation of the central kitchen.

The application of the device can ensure that the full effective utilization rate of the fuel gas reaches 99.9 percent, and the fuel gas is completely combusted without residue. Liquid fuel gas is vaporized through heat exchange, molecular bonds of the fuel gas reach a saturated state, the heat value can be completely released, the fuel gas efficiency is improved by about 18%, and the fuel gas is completely vaporized in a liquid phase without residue, so that nearly 20% of original residues are efficiently utilized. Therefore, the device can improve the LPG use efficiency by more than 30 percent for users;

the server gets rid of dependence on manual operation, can be automatically started and stopped at a plurality of time periods according to work and rest time every day, is favorable for saving power consumption and reducing labor cost, and belongs to the initiative in the domestic cognition range at the present stage; the production efficiency of gas using enterprises is improved, the labor intensity of workers is reduced, and the high-quality product rate of products is improved, so that a solid foundation and good conditions are created; taking metal cutting in the steel structure industry as an example, the production efficiency can be improved by 30% by using the conservative theory of the gas supply system, the production can be increased by 25% in two months every year, and therefore, the effective productivity of three numerical control cutting machines can be created by using the gas supply system for every two numerical control cutting machines.

The fourth concrete implementation mode: the present embodiment further describes a system for controlling an air passage for an LPG double steel tank according to the first embodiment, further including: the device comprises an alternating current power supply 20 and an alternating current switch 1, wherein the alternating current switch 1 is provided with a first contact 1-1, a second contact 1-2, a third contact 1-3 and a fourth contact 1-4; the zero line end of the alternating current power supply 20 is connected with the second contact 1-2 of the alternating current switch 1, the third contact 1-3 of the alternating current switch 1 is connected with the low level signal input end of the server 3, the live wire end of the alternating current power supply 20 is connected with the first contact 1-1 of the alternating current switch 1, and the fourth contact 1-4 of the alternating current switch 1 is connected with the level signal output end of the server 3.

The fifth concrete implementation mode: in this embodiment, a system for controlling an air passage for an LPG double steel tank according to the first embodiment is further described, and the system further includes: a power supply indicator lamp 2, a vaporizer heat preservation indicator lamp 5, a vaporizer heating indicator lamp 6, a low-pressure acousto-optic alarm lamp 9, a high-pressure acousto-optic alarm lamp 10, an A air source working indicator lamp 14 and a B air source working indicator lamp 15;

one end of the power supply indicator lamp 2 is connected with the end of the alternating current switch 1, the other end of the power supply indicator lamp 2 is connected with the end of the alternating current switch 1, one end of the vaporizer heat preservation indicator lamp 5 is connected with the low level signal input end of the server 3, the other end of the vaporizer heat preservation indicator lamp 5 is connected with the first output end 4-1 of the temperature control digital display module 4, one end of the vaporizer heating indicator lamp 6 is connected with the low level signal input end of the server 3, the other end of the vaporizer heat preservation indicator lamp 5 is connected with the second output end 4-2 of the temperature control digital display module 4, one end of the low-voltage acousto-optic alarm lamp 9 is connected with the pressure signal input end of the pressure sensor 8, the other end of the low-voltage acousto-optic alarm lamp 9 is connected with the first output end 8-1 of the pressure sensor 8, one end of the high-voltage acousto-optic alarm lamp 10 is connected with the pressure signal input end of the pressure sensor 8, the other end of high pressure audible and visual alarm lamp 10 is connected with second output 8-2 of pressure sensor 8, and the one end of A air supply work pilot lamp 14 is connected with the one end of first relay coil, and the other end of A air supply work pilot lamp 14 is connected with the other end of first relay coil, and the one end of B air supply work pilot lamp 15 is connected with the one end of second relay coil, and the other end of B air supply work pilot lamp 15 is connected with the other end of second relay coil.

In the embodiment, two channel air sources are respectively controlled and switched by two normally closed explosion-proof electromagnetic valves, a pressure gauge is arranged to display the pressure condition of the air sources, a one-way valve ensures the traveling direction singleness of the container, and the two channels are combined into one channel to be connected with a pressure transmitter to provide real-time pressure change data for a pressure monitoring computer and then connected with the air inlet end of a vaporizer; the server adopts an independent 220V power supply to start and stop at regular time through an intelligent clock-controlled computer palm controller system, controls a computer to display the working state of the vaporizer through a constant-temperature digital display, monitors and analyzes the pressure change of the air source through a pressure intelligent monitoring computer, and indicates that 99.9 percent of the air source is consumed when the pressure of the air source is reduced to a set lower limit, and then the computer gives an audible and visual alarm to prompt the switching of the air source; on-site staff immediately rotate a change-over switch, an on-site gas source is changed into a standby gas source, the standby gas source is switched on, the air pressure rises, and the gas supply is recovered to be normal; and informing the guarantee personnel to replace the steel cylinder with the purified gas source in time, and opening the valve for later use after replacement.

Claims

1. A system for controlling an air passage for an LPG double steel tank, comprising: two electromagnetic valves, a pressure sensor (8) and a server (3); two solenoid valves set up respectively on the passageway between two LPG steel tanks and gas appliances, pressure sensor (8) are used for gathering the pressure of the inside gas of current use steel bottle, the pressure signal input part of the pressure signal output part connection server (3) of pressure sensor (8), the storage battery signal input part of two solenoid valves is connected respectively to two level signal output parts of server (3), server (3) inside is equipped with minimum pressure warning value, server (3) are including comparing the module, comparing the module is used for comparing pressure signal and minimum pressure warning value, when pressure signal is less than minimum pressure warning value, server (3) send low level signal to the solenoid valve of opening and make it close, send high level signal to the solenoid valve of closing simultaneously again and make it open.

2. The system for controlling an air passage for an LPG tanlc as set forth in claim 1, further comprising: the first relay, the second relay, the third relay, the vaporizer power supply and the air source switch (11); the first relay comprises a first relay coil and a first relay switch (17), the second relay comprises a second relay coil and a second relay switch (18), and the third relay comprises a third relay coil and a third relay switch (19); the first relay switch (17), the second relay switch (18) and the third relay switch (19) are respectively provided with a first contact, a second contact, a third contact and a fourth contact; the first contact and the fourth contact are same-end contacts, the second contact and the third contact are same-end contacts, the first contact and the second contact are different-end contacts, and the third contact and the fourth contact are different-end contacts; the level signal output end of the server (3) is respectively connected with the fourth contact of the first relay switch (17), the fourth contact of the second relay coil, the fourth contact of the third relay switch (19) and the common end of the air source change-over switch (11), a third contact of the first relay switch (17) is connected with one end of the electromagnetic valve A, a third contact of the second relay coil is connected with one end of the electromagnetic valve B, a third contact of the third relay coil is connected with the negative electrode of the vaporizer power supply, two free ends of the gas source change-over switch (11) are respectively connected with one end of the first relay coil and one end of the second relay coil, and a low level signal output end of the server (3) is respectively connected with the other end of the first relay coil, the other end of the second relay coil, a first contact of the first relay switch (17), a first contact of the second relay coil and a first contact of the third relay.

3. The system for controlling the gas passage for the LPG double-steel tank as claimed in claim 2, further comprising a temperature control digital display module (4), wherein the temperature control digital display module (4) comprises a display and a temperature sensor, the temperature sensor is used for collecting the temperature inside the vaporizer, the temperature signal output end of the server (3) is connected with the temperature signal input end of the temperature control digital display module (4), a high temperature alarm value is arranged inside the server (3), when the temperature signal received by the server (3) is higher than the high temperature alarm value, the server (3) sends a temperature signal to the temperature control digital display module (4), one end of the third relay coil is connected with the temperature signal input end of the temperature control digital display module (4), and the other end of the third relay coil is connected with the second output end (4-2) of the temperature control digital display module (4).

4. The system for controlling an air passage for an LPG double steel tank as claimed in claim 3, further comprising: the device comprises an alternating current power supply (20) and an alternating current switch (1), wherein the alternating current switch (1) is provided with a first contact (1-1), a second contact (1-2), a third contact (1-3) and a fourth contact (1-4); the zero line end of the alternating current power supply (20) is connected with the second contact (1-2) of the alternating current switch (1), the third contact (1-3) of the alternating current switch (1) is connected with the low level signal input end of the server (3), the fire line end of the alternating current power supply (20) is connected with the first contact (1-1) of the alternating current switch (1), and the fourth contact (1-4) of the alternating current switch (1) is connected with the level signal output end of the server (3).

5. The system for controlling an air passage for an LPG double steel tank as claimed in claim 4, further comprising: a power supply indicator lamp (2), a vaporizer heat preservation indicator lamp (5), a vaporizer heating indicator lamp (6), a low-pressure acousto-optic alarm lamp (9), a high-pressure acousto-optic alarm lamp (10), an A air source working indicator lamp (14) and a B air source working indicator lamp (15);

one end of the power supply indicator lamp (2) is connected with the end of the alternating current switch (1), the other end of the power supply indicator lamp (2) is connected with the end of the alternating current switch (1), one end of the vaporizer heat preservation indicator lamp (5) is connected with the low level signal input end of the server (3), the other end of the vaporizer heat preservation indicator lamp (5) is connected with the first output end (4-1) of the temperature control digital display module (4), one end of the vaporizer heating indicator lamp (6) is connected with the low level signal input end of the server (3), the other end of the vaporizer heat preservation indicator lamp (5) is connected with the second output end (4-2) of the temperature control digital display module (4), one end of the low-voltage acousto-optic alarm lamp (9) is connected with the pressure signal input end of the pressure sensor (8), the other end of the low-voltage acousto-optic alarm lamp (9) is connected with the first output end (8-1) of the pressure sensor (8), the one end of high pressure reputation alarm lamp (10) is connected with the pressure signal input of pressure sensor (8), the other end of high pressure reputation alarm lamp (10) is connected with second output (8-2) of pressure sensor (8), the one end and the one end of first relay coil of A air supply work pilot lamp (14) are connected, the other end and the other end of first relay coil of A air supply work pilot lamp (14) are connected, the one end and the one end of second relay coil of B air supply work pilot lamp (15) are connected, the other end and the other end of second relay coil of B air supply work pilot lamp (15) are connected.