JP2006017657A - Gas leakage sensitivity device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lessen gas leakage in gas leakage determination by determining the gas leakage of an upper side isolation valve, even in a simultaneous energization type double isolation valve. <P>SOLUTION: A gas leakage sensitive device comprises a gas supply passage 3, a first isolation valve 4 provided in the gas supply passage 3, a second isolation valve 5 provided in a downstream side gas supply passage 3 of the first isolation valve 4, an auxiliary passage 6 formed in parallel to the second isolation valve 5, a sensing valve 7, provided in the auxiliary passage 6, a pressure sensing means 8 for sensing pressure between the first isolation valve 4 and the second isolation valve 5, and a gas leakage sensing means 9 for closing the sensing valve 7 with a set delay time from the closing of the first sensing valve 4 and the second sensing valve 5 and for sensing the leakage of the first isolation valve 4, on the basis of change of sensing pressure of the pressure-sensing means after closing the sensing valve 7. In addition, the first isolation valve 4 and the second isolation valve 5 are the simultaneous energization type valve 11. Furthermore, a piping diameter of the auxiliary passage 6 is smaller than that of the gas supply passage 3 or an orifice is provided in the auxiliary passage 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gas leak detection device that detects a gas leak of a shutoff valve provided in a gas supply path such as a boiler having a gas burner.

  In boilers and the like, a double shut-off valve is provided in the gas supply path in order to reduce the risk of gas leakage. In order to detect a gas leak in the upstream shut-off valve, when the combustion is stopped when no gas is used, the shut-off valve on the downstream side is closed after a predetermined time has passed since the shut-off valve on the upstream side is closed. When there is an increase in pressure between the two, it is determined that there is a leak in the upstream shut-off valve (see Patent Document 1).

JP 2003-130347 A

  According to such a conventional gas leak detection device, if the double shutoff valve is a simultaneous energization type, the upstream shutoff valve and the downstream shutoff valve cannot be driven separately. The method cannot be implemented. Moreover, in the conventional apparatus, gas leaks through the gas supply path between the closing of the upstream shut-off valve and the closing of the downstream shut-off valve. Therefore, the amount of gas leakage during the gas leakage determination cannot be reduced.

  The problem to be solved by the present invention is that it is possible to make a gas leak judgment of an upstream shut-off valve even with a simultaneous energization type double shut-off valve, and the amount of gas leak at the time of gas leak judgment is reduced. It is possible to reduce it.

  This invention was made in order to solve the said subject, and the invention of Claim 1 is a gas supply path, the 1st cutoff valve provided in this gas supply path, and the downstream of this 1st cutoff valve A second shutoff valve provided in the gas supply path on the side, an auxiliary passage formed in parallel with the second shutoff valve, a detection valve provided in the auxiliary passage, the first shutoff valve and the second shutoff valve A pressure detecting means for detecting the pressure between the first shut-off valve and the second shut-off valve, the detection valve is closed after a set time delay, and the detected pressure of the pressure detecting means after the detection valve is closed Gas leak detecting means for detecting leak of the first shut-off valve based on the change is provided.

    The invention according to claim 2 is characterized in that, in claim 1, the first shut-off valve 4 and the second shut-off valve 5 are simultaneously energized shut-off valves 11.

  According to the first and second aspects of the invention, the gas leakage of the upstream first shutoff valve can be detected even in the simultaneous energization type double shutoff valve.

    Furthermore, the invention described in claim 3 is characterized in that, in claim 2, the pipe diameter of the auxiliary passage 6 is made smaller than that of the gas supply passage, or an orifice is provided in the auxiliary passage.

  According to the invention described in claim 3, the amount of gas flowing out through the auxiliary passage at the time of gas leak determination can be reduced, and safety can be improved.

  According to this invention, even if it is a simultaneous energization type double shut-off valve, it is possible to determine the gas leak of the upstream shut-off valve, and to reduce the amount of gas leak at the time of gas leak judgment.

  Next, an embodiment of the present invention will be described. This embodiment is preferably implemented in a gas leak detection device such as a boiler provided with a double shutoff valve in the gas supply path, but the gas supply destination device by gas supply is not limited to the burner. .

  The outline of this embodiment will be described. This embodiment includes a gas supply path, a first cutoff valve provided in the gas supply path, a second cutoff valve provided in the gas supply path downstream of the first cutoff valve, and the second cutoff valve. An auxiliary passage formed in parallel with the valve, a detection valve provided in the auxiliary passage, a pressure detection means for detecting pressure between the first cutoff valve and the second cutoff valve, the first cutoff valve, A gas leak detecting means for closing the detection valve after a predetermined time from the closing of the second shut-off valve, and detecting a leak of the first shut-off valve based on a change in detected pressure of the pressure detecting means after the detection valve is closed; It is characterized by having.

  In this embodiment, when detecting gas leakage from the first shut-off valve, the first shut-off valve and the second shut-off valve are first closed, and then the detection valve is closed after a predetermined time. Then, when a leak occurs in the first shut-off valve, the pressure between both shut-off valves increases, and when no leak occurs, the pressure between both shut-off valves does not change. By detecting the pressure change between the two shutoff valves by the pressure means, the gas leak detection means can determine the presence or absence of gas leak in the first shutoff valve.

  Next, components of this embodiment will be described. The pipe diameter of the gas supply path is determined by the specifications of the equipment to which gas is supplied through the gas supply path. The device is a gas using device such as a gas burner.

  The first shut-off valve and the second shut-off valve have a function of interrupting the gas flow of the gas supply, and are disposed on the upstream side and the downstream side of the gas supply path, respectively. Both shut-off valves are preferably a simultaneous energizing type that can be energized (opened) and energized (stopped) only at the same time, and is an integral solenoid valve. However, it can be set as the solenoid valve which can control energization and energization stop independently.

  The auxiliary passage has a function of releasing gas existing in the passage between the two shutoff valves, and is connected to the gas supply passage so as to be in parallel with the second shutoff valve. The detection valve is provided in the auxiliary passage. And preferably, the total flow resistance of the auxiliary passage and the detection valve is the total flow resistance of the gas supply path and the second shutoff valve between the connection points to the gas supply path at both ends of the auxiliary path. It is comprised so that it may become smaller. The adjustment of the flow resistance can be realized by using a pipe having a pipe diameter smaller than that of the gas supply path, or by providing a resistor such as an orifice in the auxiliary passage, or by adjusting the flow resistance of the detection valve. it can.

  Due to such an increase in the flow resistance, the amount of gas flowing out through the auxiliary passage between the closing of the shutoff valves and the closing of the detection valve can be reduced, and particularly when the equipment used is a burner, a gas leak determination is made. The risk due to gas leaks can be reduced.

Further, the gas leak detection means controls both the shutoff valve and the detection valve, detects a change in pressure between the shutoff valves by the pressure detection means, and whether or not there is a gas leak in the first shutoff valve. It has the function to judge. More specifically, the gas leakage detection means first closes both the shutoff valves and opens the detection valves when the operation of the gas using device is stopped, and closes the detection valves after a predetermined time elapses. A pressure change in the closed space (detection space) between the valves is detected by the pressure detecting means. When the pressure rises after the detection valve is closed, control is performed to determine that there is a gas leak. The pressure detection means may have a switch function for detecting the arrival of the set pressure by itself, but may be a sensor having only a function for detecting pressure.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic explanatory view of a boiler for carrying out the present invention, and FIG. 2 is a time chart for explaining the operation of the embodiment.

  First, referring to FIG. 1, the gas leak detection device of this embodiment includes a gas supply path 3 that supplies gas to the burner 2 of the boiler 1, a first shut-off valve 4 provided in the gas supply path 3, A second shutoff valve 5 provided in the gas supply path 3 downstream of the first shutoff valve 4, an auxiliary passage 6 formed in parallel with the second shutoff valve 5, and a detection valve provided in the auxiliary passage 6 7, a pressure switch 8 for detecting the pressure between the first shut-off valve 4 and the second shut-off valve 5, and a controller 9 as a gas leak detecting means for detecting a leak of the first shut-off valve 4; As a main part.

  The burner 2 is a gas burner that burns gas fuel. The shut-off valves 4 and 5 are provided in series with the gas supply path 3, and when the combustion operation of the burner 2 is started, the fuel valves 4 and 5 are opened, and when the combustion operation is stopped, the both shut-off valves are shut off. The valves 4 and 5 are closed.

  Both the shut-off valves 4 and 5 are configured as a simultaneous shut-off type and an integral double shut-off valve 11. The simultaneous energization type is a solenoid valve of a type that performs simultaneous energization and simultaneous energization stop, in which the shutoff valves 4 and 5 cannot be controlled independently. The integral type is an electromagnetic valve in which the both shut-off valves are integrated. In this embodiment, they are integrated, but the first pipe 12 between the shut-off valves 4 and 5 is exposed so that the auxiliary passage 7 described later can be connected. However, an integrated double shut-off valve having a connection port (not shown) that connects between the shut-off valves 4 and 5 and to which the auxiliary passage 7 can be connected can be provided.

  The burner 2 is provided with a blower passage 13 for supplying combustion air and supplying purge air such as pre-purge and post-purge.

  The auxiliary passage 6 has a pipe diameter smaller than that of the gas supply path 3.

  Next, a control configuration by the controller 9 will be described. The controller 9 inputs signals from a load detection sensor 15 for detecting the pressure (load) in the pressure switch 8 and the boiler body 14 of the boiler 1, and the both shut-off valves 4, 5, and the detection valves 7 and the water supply pump 16 to the can body 14 are controlled. The control by the controller 9 includes combustion control for controlling the combustion of the burner 2 so that the signal of the load detection sensor 15 becomes a set value, and the water level in the can body 14 by controlling the feed water feed water 16. And water supply control for controlling to a set value. The combustion control includes gas leak detection control, which is a feature of the present invention. These controls are executed by a control procedure stored in advance.

Here, the gas leak detection operation of the first shutoff valve 4 according to this embodiment will be described below with reference to FIG. The detection of the leakage state of the first shutoff valve 4 is performed when the combustion of the burner 2 is stopped. The shutoff valves 4 and 5 are closed to end the combustion operation. Then, the controller 9 closes the first cutoff valve 4 and the second cutoff valve 5 and opens the detection valve 7. This state is held for the first set time T1. Thereby, the gas which exists in the 1st pipe line 12 between the said both shut-off valves 4 and 5 flows out into the said burner 2 side via the said auxiliary | assistant channel | path 6. FIG. As a result, the pressure (detected pressure) in the first pipe 12 drops as shown by the curve A in FIG. 2, and when the pressure reaches the first set pressure P1, the pressure switch 8 changes from ON to OFF. The pressure finally reaches the second set pressure P2.

  When the first set time T1 elapses, the controller 9 performs pressure monitoring during the second set time T2. Here, if a gas leak occurs in the first shutoff valve 4, the detected pressure starts to rise as shown by a curve B in FIG. 2, exceeds the first set pressure P1, and the pressure switch 8 Turns on. Thereby, the said controller 9 determines with the said 1st cutoff valve 4 having gas leak, and alarms gas leak with the alarm device which is not shown in figure. Conversely, when the detected pressure does not change, it is determined that there is no leakage of the first shutoff valve 4.

  The present invention is not limited to the embodiment described above, and both the shut-off valves 4 and 5 can be electromagnetic valves that can be controlled independently. In this case, the both shut-off valves 4 and 5 are configured to be controlled simultaneously by the controller 9 when determining gas leakage.

  In the embodiment, the gas switch is detected by using the pressure switch 8, but the pressure is detected by a simple pressure sensor (not shown), and the controller 9 exceeds the first set pressure P1. Can be configured to determine that.

It is a schematic explanatory drawing of the boiler which implements this invention. It is a time chart explaining operation | movement of the Example.

Explanation of symbols

3 Gas supply path 4 First shut-off valve
5 Second shut-off valve 6 Auxiliary passage 7 Detection valve 8 Pressure detection means 9 Controller

Claims (3)

  A gas supply path 3; a first cutoff valve 4 provided in the gas supply path 3; a second cutoff valve 5 provided in the gas supply path 3 on the downstream side of the first cutoff valve 4; An auxiliary passage 6 formed in parallel with the valve 5, a detection valve 7 provided in the auxiliary passage 6, and a pressure detection means 8 for detecting the pressure between the first shut-off valve 4 and the second shut-off valve 5; The detection valve 7 is closed after a set time delay from the closing of the first shutoff valve 4 and the second shutoff valve 5, and the first pressure based on the change in the detected pressure of the pressure detection means 8 after the detection valve 7 is closed. A gas leak detection device comprising gas leak detection means 9 for detecting a leak of the shut-off valve 4.   The gas leak detection device according to claim 1, wherein the first shut-off valve 4 and the second shut-off valve 5 are simultaneously energized shut-off valves 11.   The gas leak detection device according to claim 1 or 2, wherein a pipe diameter of the auxiliary passage (6) is made smaller than that of the gas supply passage (3) or an orifice is provided in the auxiliary passage (6).

Images