阅读说明：本技术 Lng车用瓶及其自增压系统、自增压方法 (LNG vehicle bottle and self-pressurization system and method thereof ) 是由 刘宏伟 王鑫东 龚伟 秦海兵 俞渊 刘岗 于 2019-11-06 设计创作，主要内容包括：本发明提供一种LNG车用瓶及其自增压系统、自增压方法。LNG车用瓶的自增压系统包括连接于LNG车用瓶的取液口至回气口之间的自增压管路及设置于自增压管路上的汽化器,自增压系统还包括电磁切断阀、压力检测机构和控制机构。电磁切断阀包括阀体和电磁线圈；阀体设置于自增压管路上以控制自增压管路与LNG车用瓶之间的通断；压力检测机构设置于自增压管路上,用于检测LNG车用瓶的气相空间的实时压力值；控制机构分别与电磁线圈和压力检测机构电连接；压力检测机构检测到LNG车用瓶的实时压力低于第一预设压力值时,控制机构控制进行自增压；在压力检测机构检测到LNG车用瓶的压力到达第二预设压力值时,控制机构控制停止自增压。(The invention provides an LNG vehicle bottle, a self-pressurization system and a self-pressurization method thereof. The self-pressurization system of the LNG vehicle bottle comprises a self-pressurization pipeline connected between a liquid taking port and a gas return port of the LNG vehicle bottle and a vaporizer arranged on the self-pressurization pipeline, and further comprises an electromagnetic cut-off valve, a pressure detection mechanism and a control mechanism. The electromagnetic cut-off valve comprises a valve body and an electromagnetic coil; the valve body is arranged on the self-pressurization pipeline to control the connection and disconnection between the self-pressurization pipeline and the LNG vehicle bottle; the pressure detection mechanism is arranged on the self-pressurization pipeline and used for detecting a real-time pressure value of a gas phase space of the LNG vehicle bottle; the control mechanism is respectively electrically connected with the electromagnetic coil and the pressure detection mechanism; when the pressure detection mechanism detects that the real-time pressure of the LNG vehicle bottle is lower than a first preset pressure value, the control mechanism controls self-pressurization; when the pressure detection mechanism detects that the pressure of the LNG vehicle bottle reaches a second preset pressure value, the control mechanism controls the stop of self-pressurization.)

1. The utility model provides a self-pressurization system of automobile-used bottle of LNG, including connect in the automobile-used bottle of LNG get between liquid mouth to the return-air port from the booster circuit and set up in vaporizer on the self-pressurization pipeline, its characterized in that, self-pressurization system still includes:

the electromagnetic cut-off valve comprises a valve body and an electromagnetic coil; the valve body is arranged on the self-pressurization pipeline to control the connection and disconnection between the self-pressurization pipeline and the LNG vehicle bottle;

the pressure detection mechanism is arranged on the self-pressurization pipeline and used for detecting the real-time pressure value of the gas phase space of the LNG vehicle bottle;

the control mechanism is electrically connected with the electromagnetic coil and the pressure detection mechanism respectively;

when the pressure detection mechanism detects that the real-time pressure of the LNG vehicle bottle is lower than a first preset pressure value, the control mechanism controls the electromagnetic coil to be electrified so as to open the valve body and further perform self-pressurization; when the pressure detection mechanism detects that the pressure of the LNG vehicle bottle reaches a second preset pressure value, the control mechanism controls the electromagnetic coil to be powered off to close the valve body and stop self-pressurization; the first preset pressure value is smaller than or equal to a second preset pressure value.

2. The self-pressurization system for LNG vehicle bottles of claim 1, wherein said electromagnetic shut-off valve is disposed between said liquid take-off port and said vaporizer.

3. The self-pressurization system of an LNG vehicle bottle according to claim 1, characterized in that the electromagnetic shut-off valve is a normally closed electromagnetic shut-off valve.

4. The self-pressurization system for bottles of LNG vehicles of claim 1, wherein said first preset pressure value is not greater than the lowest pressure value of the gas required for the engine of the LNG vehicle to be able to work; the second pressure preset value is larger than the lowest pressure value of gas required by the engine of the LNG vehicle to work and is not larger than the design pressure of the LNG vehicle bottle.

5. The self-pressurization system for LNG vehicle bottles of claim 1, wherein said pressure detection mechanism is a pressure sensor and is disposed near a return air port of said LNG vehicle bottle.

6. The self-pressurization system for LNG vehicle bottles of claim 1, further comprising a combustible gas detection mechanism for detecting whether there is a leakage of combustible gas; the combustible gas detection mechanism is positioned above the self-pressurization pipeline and is electrically connected with the control mechanism, and the control mechanism controls the electromagnetic cut-off valve to be closed according to information transmitted by the combustible gas detection mechanism;

the combustible gas detection mechanism adopts an explosion-proof structure.

7. The self-pressurization system of a bottle for LNG vehicle as claimed in claim 1, wherein said control mechanism adopts an explosion-proof structure; the electromagnetic cut-off valve adopts an explosion-proof structure.

8. A LNG vehicle cylinder comprising a gas cylinder and a self-pressurizing system as claimed in any one of claims 1 to 7; the gas cylinder is provided with a liquid taking port and a gas return port, and a self-pressurization pipeline of the self-pressurization system is connected between the liquid taking port and the gas return port.

9. A self-pressurization method of an LNG vehicle bottle, characterized in that the self-pressurization system of an LNG vehicle bottle according to any one of claims 1 to 7 is used; the self-pressurization method comprises the following steps:

detecting a real-time pressure value in the LNG vehicle bottle at present; when the real-time pressure value is lower than the first pressure preset value, the control mechanism controls the electromagnetic coil to be electrified so as to open the valve body to carry out self-pressurization;

detecting a real-time pressure value in the LNG vehicle bottle at present; when the real-time pressure value reaches the second pressure preset value, the control mechanism controls the electromagnetic coil to be powered off to close the valve body and stop self-pressurization.

10. The self-pressurization method for LNG vehicle bottles of claim 9,

detecting whether combustible gas exists above the self-pressurization pipeline in real time; when combustible gas is detected, the control mechanism controls the electromagnetic coil to be powered off to close the valve body.

Technical Field

The invention relates to the technical field of natural gas fuel supply, in particular to an LNG vehicle bottle and a self-pressurization system and a self-pressurization method thereof.

Background

With the rapid development pace of natural gas technology in the world, Liquefied Natural Gas (LNG) is widely used in many fields as a green energy source recognized in the world today. The development in the automobile industry is particularly prominent, and the research and development of LNG automobiles are of great significance for saving energy and improving urban atmospheric quality.

The gas cylinder is the fuel storage equipment of LNG car, and under the prerequisite that the gas cylinder provided stable fuel supply for the engine, the car just can be stably driven. As the gas cylinder continuously conveys LNG to the engine, the liquid level in the gas cylinder is reduced, the gas phase space is increased, and the pressure in the gas cylinder is gradually reduced, so that the gas supply pressure of the engine cannot be met. This requires pressurizing the cylinder to ensure stable delivery of fuel, i.e., a self-pressurizing system for the cylinder.

At present, a self-pressurization system of an LNG vehicle bottle mostly adopts the method that low-temperature liquid is taken from a liquid taking port of the vehicle bottle, flows through a liquid phase stop valve, a flow passing valve and a pressure regulating valve (spring thimble type) in sequence, flows to a vaporizer to be vaporized into gas, and then returns to the upper layer gas phase space in a gas bottle through a one-way valve and a gas phase stop valve. However, the setting of the pressure range value of the self-pressurization system is influenced by a pressure regulating valve structure (a spring thimble type), so that the pressure range value is inaccurate in a low-temperature environment, a loop is not cut off when the pressure range value is higher than a set value, and the pressurization cannot be accurately stopped; and when the pressure is lower than the set value, the LNG vehicle bottle is not opened, and the pressurization cannot be accurately carried out, so that the LNG vehicle bottle stops supplying gas to an engine of the LNG vehicle.

Disclosure of Invention

The invention aims to provide an LNG vehicle bottle capable of accurately performing pressurization and stopping pressurization, a self-pressurization system thereof and a self-pressurization method thereof, so as to solve the problems in the prior art.

In order to solve the above technical problem, the present invention provides a self-pressurization system for an LNG vehicle bottle, including a self-pressurization pipeline connected between a liquid inlet and a return air inlet of the LNG vehicle bottle, and a vaporizer disposed on the self-pressurization pipeline, the self-pressurization system further including: the electromagnetic cut-off valve comprises a valve body and an electromagnetic coil; the valve body is arranged on the self-pressurization pipeline to control the connection and disconnection between the self-pressurization pipeline and the LNG vehicle bottle; the pressure detection mechanism is arranged on the self-pressurization pipeline and used for detecting the real-time pressure value of the gas phase space of the LNG vehicle bottle; the control mechanism is electrically connected with the electromagnetic coil and the pressure detection mechanism respectively; when the pressure detection mechanism detects that the real-time pressure of the LNG vehicle bottle is lower than a first preset pressure value, the control mechanism controls the electromagnetic coil to be electrified so as to open the valve body and further perform self-pressurization; when the pressure detection mechanism detects that the pressure of the LNG vehicle bottle reaches a second preset pressure value, the control mechanism controls the electromagnetic coil to be powered off to close the valve body and stop self-pressurization; the first preset pressure value is smaller than or equal to a second preset pressure value.

In one embodiment, the electromagnetic shut-off valve is disposed between the liquid taking port and the vaporizer.

In one embodiment, the electromagnetic shut-off valve is a normally closed electromagnetic shut-off valve.

In one embodiment, the first preset pressure value is not greater than the lowest pressure value of gas required by the engine of the LNG truck to work; the second pressure preset value is larger than the lowest pressure value of gas required by the engine of the LNG vehicle to work and is not larger than the design pressure of the LNG vehicle bottle.

In one embodiment, the pressure detection mechanism is a pressure sensor and is disposed near a return air port of the LNG vehicle bottle.

In one embodiment, the device further comprises a combustible gas detection mechanism for detecting whether combustible gas leaks; the combustible gas detection mechanism is positioned above the self-pressurization pipeline and is electrically connected with the control mechanism, and the control mechanism controls the electromagnetic cut-off valve to be closed according to information transmitted by the combustible gas detection mechanism; the combustible gas detection mechanism adopts an explosion-proof structure.

In one embodiment, the control mechanism adopts an explosion-proof structure; the electromagnetic cut-off valve adopts an explosion-proof structure.

The invention also provides an LNG vehicle bottle, which comprises a gas bottle and the self-pressurization system; the gas cylinder is provided with a liquid taking port and a gas return port, and a self-pressurization pipeline of the self-pressurization system is connected between the liquid taking port and the gas return port.

The invention also provides a self-pressurization method of the LNG vehicle bottle, which adopts the self-pressurization system of the LNG vehicle bottle; the self-pressurization method comprises the following steps:

detecting a real-time pressure value in the LNG vehicle bottle at present; when the real-time pressure value is lower than the first pressure preset value, the control mechanism controls the electromagnetic coil to be electrified so as to open the valve body to carry out self-pressurization;

detecting a real-time pressure value in the LNG vehicle bottle at present; when the real-time pressure value reaches the second pressure preset value, the control mechanism controls the electromagnetic coil to be powered off to close the valve body and stop self-pressurization.

In one embodiment, whether combustible gas exists or not is detected in real time above the self-pressurization pipeline; when combustible gas is detected, the control mechanism controls the electromagnetic coil to be powered off to close the valve body.

According to the technical scheme, the invention has the advantages and positive effects that:

the self-pressurization system of the LNG vehicle bottle comprises a control mechanism, a self-pressurization pipeline connected between a liquid taking port and an air return port of the LNG vehicle bottle, and a vaporizer, an electromagnetic cut-off valve and a pressure detection mechanism which are arranged on the self-pressurization pipeline. The pressure detection mechanism is used for detecting a real-time pressure value of a gas phase space of the LNG vehicle bottle, and the control mechanism controls the electromagnetic cut-off valve to be opened to realize self pressurization when the pressure detection mechanism detects that the real-time pressure of the LNG vehicle bottle is lower than a first preset pressure value; when the pressure detection mechanism detects that the pressure of the LNG vehicle bottle reaches a second preset pressure value, the control mechanism controls the electromagnetic cut-off valve to be closed to stop self-pressurization; the first preset pressure value is less than or equal to the second preset pressure value. The self-pressurization accurate opening or the accurate stopping is realized through the cooperation of the pressure detection mechanism, the electromagnetic cut-off valve and the control mechanism.

Drawings

FIG. 1 is a schematic structural diagram of one embodiment of a LNG vehicle bottle of the invention;

the reference numerals are explained below:

1. a gas cylinder; 11. a liquid taking port; 12. an air return port; 2. a self-pressurization system; 21. a self-pressurizing pipeline; 22. an electromagnetic cut-off valve; 23. a vaporizer; 24. a one-way valve; 25. a gas phase stop valve; 26. a pressure detection mechanism; 27. a combustible gas detection mechanism; 28. and a control mechanism.

Detailed Description

Exemplary embodiments that embody features and advantages of the invention are described in detail below in the specification. It is to be understood that the invention is capable of other embodiments and that various changes in form and details may be made therein without departing from the scope of the invention and the description and drawings are to be regarded as illustrative in nature and not as restrictive.

For further explanation of the principles and construction of the present invention, reference will now be made in detail to the preferred embodiments of the present invention, which are illustrated in the accompanying drawings.

Referring to fig. 1, the present invention provides a LNG vehicle cylinder, which includes a gas cylinder 1 and a self-pressurization system 2.

The gas cylinder 1 has a liquid take-out port 11 and a gas return port 12. The liquid taking port 11 is communicated with the liquid phase space of the gas cylinder 1, and the gas return port 12 is communicated with the gas phase space of the gas cylinder 1.

The self-pressurization system 2 is used for pressurizing the gas cylinder 1, and mainly comprises a self-pressurization pipeline 21, a control mechanism 28, and an electromagnetic cut-off valve 22, a vaporizer 23, a one-way valve 24, a gas phase cut-off valve 25 and a pressure detection mechanism 26 which are sequentially arranged on the self-pressurization pipeline 21.

The self-pressurization pipeline 21 is connected between the liquid taking port 11 and the gas return port 12 of the gas cylinder 1. Specifically, the self-pressurizing line 21 has an inlet end and an outlet end. The inlet end is communicated with the liquid taking port 11, and the outlet end is communicated with the air return port 12.

The electromagnetic cut-off valve 22 is arranged on the self-pressurization pipeline 21 and used for controlling the connection and disconnection between the self-pressurization pipeline 21 and the gas cylinder 1. Specifically, the solenoid cut-off valve 22 is close to the inlet end, so that the cryogenic liquid in the gas cylinder 1 can flow to the vaporizer 23 located downstream of the solenoid cut-off valve 22 by the opening of the solenoid cut-off valve 22.

The electromagnetic shut-off valve 22 includes a valve body and an electromagnetic coil. The valve body is arranged on the self-pressurization pipeline 21 to control the connection and disconnection between the self-pressurization pipeline 21 and the liquid taking port 11 of the gas cylinder 1. Specifically, in the present embodiment, the electromagnetic shut-off valve 22 is a normally closed electromagnetic shut-off valve 22, that is, the valve body is in a closed state when the electromagnetic coil of the electromagnetic shut-off valve 22 is not energized, and the valve body is in an open state after the electromagnetic coil is energized.

Further, the electromagnetic cut-off valve 22 is of an explosion-proof structure. And the electromagnetic shut-off valve 22 is also resistant to low temperatures.

A vaporizer 23 is located downstream of the solenoid shut-off valve 22 for vaporizing the cryogenic liquid into a gas. The vaporizer 23 may be configured in a manner similar to that of the related art, such as an air-temperature type, a water-bath type, etc., which will not be described in detail herein.

A check valve 24 is located downstream of the vaporizer 23 and allows only the gas vaporized by the vaporizer 23 to pass in the upstream-to-downstream direction for preventing the gas from being poured back into the vaporizer 23.

The gas shutoff valve 25 is located downstream of the check valve 24, and the gas can be delivered, and the flow rate of the delivered gas can be shut off or adjusted by opening, closing or adjusting the degree of opening of the gas shutoff valve 25.

The pressure detection mechanism 26 is disposed downstream of the gas phase cut-off valve 25 and near the return port 12 of the gas cylinder 1, and detects a real-time pressure value of the gas phase space of the gas cylinder 1 by communicating with the gas phase space of the gas cylinder 1 through the self-pressurization pipeline 21 and the return port 12.

Specifically, in the present embodiment, the pressure detection mechanism 26 is a pressure sensor.

The electromagnetic cut-off valve 22 is opened, the gas cylinder 1 is communicated with the self-pressurization pipeline 21, low-temperature liquid of the gas cylinder 1 flows to the vaporizer 23 through the liquid taking port 11, the low-temperature liquid is vaporized by the vaporizer 23 to form gas, and then the gas sequentially passes through the one-way valve 24 and the gas phase cut-off valve 25 and enters the gas phase space of the gas cylinder 1 through the gas return port 12, so that the pressure in the gas cylinder 1 is increased, and the accurate self-pressurization process is realized.

The electromagnetic cut-off valve 22 is closed to cut off the communication between the gas cylinder 1 and the self-pressurization line 21, and the pressurization is accurately stopped.

This application replaces liquid phase stop valve, excess flow valve and air-vent valve through electromagnetism trip valve 22, has not only simplified from turbocharging system 2, has still reduced the resistance from among the turbocharging pipeline 21, and then has improved the speed of the cryogenic liquids flow direction vaporizer 23 in the gas cylinder 1, and then has improved the pressure boost speed.

After the liquid phase stop valve is replaced, the leakage of combustible gas at the sealing position of the valve body and the valve core of the liquid phase stop valve in a low-temperature environment is avoided, and the leakage probability of the self-pressurization pipeline 21 is effectively reduced.

After replacing the excess flow valve, the situation that the excess flow valve can not effectively cut off the self-pressurization pipeline 21 in a low-temperature environment is avoided, the self-pressurization pipeline 21 is cut off by closing the electromagnetic cut-off valve 22, and then the communication between the self-pressurization pipeline 21 and the liquid outlet of the gas cylinder 1 is effectively cut off.

The control mechanism 28 is electrically connected to the solenoid and the pressure detection mechanism 26, respectively. In this embodiment, the control mechanism 28 is electrically connected to the coil and the pressure detection mechanism 26 through electric wires, respectively.

Specifically, the control mechanism 28 is of an explosion-proof construction.

The control mechanism 28 is electrically connected to the pressure detection mechanism 26 to receive the real-time pressure value of the gas cylinder 1 detected by the pressure detection mechanism 26, and when the real-time pressure value reaches a first preset pressure value, the control mechanism 28 controls the electromagnetic coil to be electrified to open the valve body, so as to start to self-pressurize the gas cylinder 1. The control mechanism 28 receives the real-time pressure value of the gas cylinder 1 detected by the pressure detection mechanism 26, and when the real-time pressure value reaches a second preset pressure value, the control mechanism 28 controls the electromagnetic coil to be powered off to close the valve body so as to stop self-pressurization.

Specifically, the first preset pressure value is smaller than the second preset pressure value. The first pressure preset value is not larger than the lowest pressure value of gas required by the engine of the LNG vehicle to work, and the first pressure preset value is lower than the first pressure preset value, so that the engine of the LNG vehicle cannot work. The second preset pressure value is greater than or equal to the first preset pressure value. The second pressure preset value is larger than the lowest pressure value of gas required by the engine of the LNG vehicle to work and is not larger than the design pressure of the gas cylinder 1.

For example, the minimum pressure value of the gas required for the engine operation of an LNG vehicle is 1.0Mpa, and the design pressure of the gas cylinder 1 is 1.5 Mpa. At this time, the first preset pressure value can be designed to be 0.8Mpa, 0.9Mpa or 1.0Mpa, and the second preset pressure value can be designed to be 1.0Mpa, 1.2Mpa or 1.3Mpa, etc. When the first pressure preset value and the second pressure preset value are both 1.0Mpa, namely, the pressure is increased when the pressure is lower than 1.0Mpa, and the pressure is stopped when the pressure reaches 1.0 Mpa.

Further, the self-pressurization system 2 further includes a combustible gas detection mechanism 27 for detecting whether there is a leakage of combustible gas. Specifically, the combustible gas detection mechanism 27 is disposed above the self-pressurization line 21.

The combustible gas detection mechanism 27 is electrically connected with the control mechanism 28 and is conveyed to the control mechanism 28 when detecting a signal with combustible gas, so that the control mechanism 28 controls the power-off of the electromagnetic coil according to the signal to close the valve body, further the communication between the self-pressurization pipeline 21 and the gas cylinder 1 is cut off, the source of the combustible gas is stopped, the leakage of the combustible gas is avoided, and the use safety of the gas cylinder 1 is ensured.

In this embodiment, the combustible gas detection means 27 is of an explosion-proof structure, and is connected to the control means 28 by an electric wire.

The invention also provides a self-pressurization method of the LNG vehicle bottle, and the self-pressurization system 2 comprises the following steps:

and S1, detecting the real-time pressure value of the gas phase space in the gas cylinder 1, and comparing the real-time pressure value with a first pressure preset value.

And S2, when the real-time pressure value is lower than the first pressure preset value, controlling the electromagnetic coil to be electrified to open the valve body, and pressurizing the gas cylinder 1 by the self-pressurization system 2.

Specifically, the first preset pressure value is smaller than the second preset pressure value. The first pressure preset value is not larger than the lowest pressure value of gas required by the engine of the LNG vehicle to work, and the first pressure preset value is lower than the first pressure preset value, so that the engine of the LNG vehicle cannot work.

After the gas cylinder 1 is filled with liquefied natural gas with lower saturated vapor pressure through the gas filling station or after the gas cylinder 1 continuously supplies gas and the pressure is reduced, the real-time pressure value of the gas cylinder 1 is lower than the first pressure preset value.

The control mechanism 28 controls the electromagnetic coil to be electrified to open the valve body, so that the low-temperature liquid in the gas cylinder 1 flows to the self-pressurization system 2 through the liquid taking port 11. The vaporizer 23 of the self-pressurization system 2 vaporizes the low-temperature liquid into gas, and the gas enters the gas phase space of the gas cylinder 1 through the gas return port 12 after passing through the one-way valve 24 and the gas phase stop valve 25, so that the pressure in the gas cylinder 1 is increased, and the purpose of pressurization is achieved.

And S3, when the real-time pressure value reaches the second pressure preset value, controlling the electromagnetic coil to be powered off to close the valve body, and stopping pressurizing.

Specifically, the second pressure preset value is greater than or equal to the first pressure preset value. Wherein the second pressure preset value is greater than or equal to the first pressure preset value. The second pressure preset value is larger than the lowest pressure value of gas required by the engine of the LNG vehicle to work and is not larger than the design pressure of the gas cylinder 1.

S4, detecting whether combustible gas exists above the self-pressurization pipeline 21 in real time; upon detection of the presence of combustible gas, the control mechanism 28 controls the solenoid to de-energize causing the valve body to close.

During the self-pressurization of the self-pressurization system 2, the combustible gas detection mechanism 27 simultaneously detects whether there is a combustible gas leak from the self-pressurization system 2, and sends the signal to the control mechanism 28.

If detect combustible gas, control mechanism 28 control electromagnetism trip valve 22 closes, and cuts off the intercommunication between self-pressurization system 2 and the gas cylinder 1, has stopped combustible gas's source, and then has avoided combustible gas's leakage, has guaranteed the safe in utilization of the automobile-used bottle of LNG.

If the combustible gas is not detected, the control means 28 does not send a command in accordance with the signal from the combustible gas detection means 27.

It is specifically noted that in other embodiments, the control mechanism 28 may not be limited to its physical state, i.e., the control mechanism 28 in the above-described embodiments may be a separate structure, integrated with a display in the LNG vehicle, or integrated with a level gauge transmitter of the LNG vehicle bottle.

According to the technical scheme, the invention has the advantages and positive effects that:

the self-pressurization system of the LNG vehicle bottle comprises a control mechanism, a self-pressurization pipeline connected between a liquid taking port and an air return port of the LNG vehicle bottle, and a vaporizer, an electromagnetic cut-off valve and a pressure detection mechanism which are arranged on the self-pressurization pipeline. The pressure detection mechanism is used for detecting a real-time pressure value of a gas phase space of the LNG vehicle bottle, and the control mechanism controls the electromagnetic cut-off valve to be opened to realize self pressurization when the pressure detection mechanism detects that the real-time pressure of the LNG vehicle bottle is lower than a first preset pressure value; when the pressure detection mechanism detects that the pressure of the LNG vehicle bottle reaches a second preset pressure value, the control mechanism controls the electromagnetic cut-off valve to be closed to stop self-pressurization; the first preset pressure value is less than or equal to the second preset pressure value. The self-pressurization accurate opening or the accurate stopping is realized through the cooperation of the pressure detection mechanism, the electromagnetic cut-off valve and the control mechanism.

While the present invention has been described with reference to several exemplary embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration, rather than of limitation. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.