JPH0442617Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a gas cutoff valve used as a safety device for a piping system that supplies gaseous fuel.

Conventional Technology In recent years, city gas supply companies and the LP gas supply industry have installed gas meters that measure gas usage as a means of ensuring safety and security when using gas. We are considering installing a gas cutoff valve to close the passage.

An example of the conventional gas cutoff valve mentioned above will be described below with reference to the drawings.

FIG. 2 shows a longitudinal sectional view of a conventional gas cutoff valve. In FIG. 2, a permanent magnet 2 is placed at the bottom of a U-shaped magnetic yoke 1, a core piece 3 is attracted onto it, and a non-magnetic metal guide pipe 4 is fitted outside the permanent magnet and core piece.
Further, an electromagnetic coil 6 wound around a coil bobbin 5 is fitted onto the outer periphery of the guide pipe 4, and a yoke 7 is further fitted onto the coil bobbin 5.
Cut-and-raised portions 1a are provided on both sides of the yoke 1, and a support 8 is fastened and fixed to the cut-and-raised portions with screws. On the other hand, the movable part of the gas cutoff valve has a structure in which the plunger 9 is inserted into the guide pipe 4 with a valve rubber 10 fitted and attached to the tip of the plunger 9. An O-ring 11 is used inside the guide pipe 4, and an O-ring 12 is used outside the guide pipe 4 to airtightly isolate the gas passage side where the valve rubber 10 is located and the atmosphere side where the coil 6 and yoke 1 are located.

Regarding the gas cutoff valve configured as above,
The operation will be explained below.

First, when the plunger 9 is pushed in with the setting rod 16, the attraction force of the permanent magnet 2, which is greater than the reaction force of the spring 13, is applied to the plunger 9 and the core piece 3.
It forms on the suction surface between the two and is held as it is by suction.
In this state, the valve rubber 10 is in an open state with the valve seat 14,
In other words, the valve is in an open state.

When the valve is closed, when the electromagnetic coil 6 is instantaneously energized in a direction that generates lines of magnetic force in the opposite direction to the permanent magnet 2, the attraction force between the core piece 3 and the plunger 9 decreases, and the reaction force of the spring 13 becomes relative. The plunger 9 separates from the core piece 3 and the valve rubber 10 closes the valve seat 14.

Problems to be Solved by the Invention However, in the above configuration, since the attracting surfaces of the core piece 3 and the permanent magnet 2 are fixed only by the magnetic force of the permanent magnet 2, the electromagnetic coil 6
Instantly energizes the plunger 9 and core piece 3.
When the magnetic force acts so that the core piece 3 and the permanent magnet 2 are detached, the attracting surfaces of the core piece 3 and the permanent magnet 2 may detach first, and the current value flowing through the electromagnetic coil 6 at the time of detachment is not constant, resulting in very unstable reliability. It was not working properly.

In view of the above-mentioned problems, the present invention prevents the attraction surfaces of the core piece and permanent magnet from separating before the plunger and core piece separate, and provides a reliable gas cutoff valve with a stable operating current value. It is something to do.

Means for Solving the Problems In order to solve the above problems, the gas cutoff valve of the present invention includes a permanent magnet that normally attracts a plunger having the valve at one end via a core piece to close the gas passage; An electromagnetic coil that excites a magnetic field in the opposite direction to the magnetic field of the permanent magnet in the event of an abnormality, causing the plunger to separate from the core piece and close the gas passage; A guide pipe installed in the
A bypass portion is provided between the core piece and the yoke to allow magnetic flux to flow directly from the core piece to the yoke.

Effects The present invention has the above-described configuration, so that before a current instantaneously flows through the electromagnetic coil and the plunger and the core piece are separated from the magnetic force of the permanent magnet, the attraction surface of the core piece and the permanent magnet is connected to the bypass portion of the core piece. Because it is attracted by magnetic force, it will not come off. Therefore, when the current flowing through the electromagnetic coil reaches a certain predetermined value, the attraction surfaces of the core piece and the plunger are always separated, and the gas passage is closed by the valve.

Example The following is a gas cutoff valve according to an example of the present invention.
This will be explained with reference to the drawings.

FIG. 1 shows a longitudinal sectional view of a gas cutoff valve in one embodiment of the present invention. In Figure 1,
A permanent magnet 2 is placed at the bottom of a U-shaped magnetic yoke 1, a core piece 3 is placed on top of the permanent magnet 2, a non-magnetic metal guide pipe 4 is fitted outside the permanent magnet and the core piece, and the guide pipe 4 is An electromagnetic coil 6 wound around a coil bobbin 5 is fitted around the outer periphery, and a yoke 7 is further fitted onto the coil bobbin 5. The core piece 3 is provided with a magnetic bypass section 3a. Further, cut-and-raised portions 1a are provided on both sides of the yoke 1, and a support 8 is fastened and fixed to the cut-and-raised portions with screws. on the other hand,
The movable part of the gas cutoff valve has a structure in which the plunger 9 is inserted into the guide pipe 4, with a valve rubber 10 fitted and attached to the tip of the plunger 9. An O-ring 11 is used inside the guide pipe 4, and an O-ring 12 is used outside the guide pipe 4 to airtightly isolate the gas passage side where the valve rubber 10 is located and the atmosphere side where the coil 6 and yoke 1 are located.

Regarding the gas cutoff valve configured as above,
The operation will be explained below using FIG.

FIG. 1 is a longitudinal cross-sectional view of the gas cutoff valve when the valve rubber 10 of the gas cutoff valve is open and the gas passage is open during normal operation. First, when the plunger 9 is pushed in with the setting rod 16, the plunger 9 moves and comes into contact with the core piece 3, and a suction force greater than the reaction force of the spring 13 is applied to the yoke 1, the yoke 7, the plunger 9, and the core piece 3. Due to the magnetic flux of the permanent magnet 2 flowing through the plunger 9 and the core piece 3,
It forms on the suction surface between the parts and is held as it is by suction. In this state, the valve rubber 10 separates from the valve seat 14, the valve becomes open, and gas begins to flow in the direction of the arrow.

In the event of an abnormality, when the electromagnetic coil 6 is instantaneously energized to generate a magnetic field in the opposite direction to that of the permanent magnet 2,
Magnetic force is generated by the electromagnetic coil 6 to reduce the attraction force between the core piece 3 and the plunger 9 and the attraction force between the permanent magnet 2 and the core piece 3, but the attraction force between the core piece 3 and the permanent magnet 2 is reduced by the core piece. Since the magnetic flux flowing through the bypass portion 3a is greater than the attraction force of the attraction surface between the core piece 3 and the plunger 9, the attraction surface between the plunger 9 and the core piece 3 is reliably separated.

Effects of the invention As described above, this invention provides a bypass section between the core piece and the yoke for the magnetic flux directly from the core piece to the yoke, so the magnetic force generated by instantaneously energizing the electromagnetic coil in the event of an abnormality, etc. Since the attracting surface between the permanent magnet and the core piece does not separate, and the attracting surface between the plunger and the core piece reliably separates, it is possible to create a reliable gas cutoff valve with a stable operating current value.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a gas cutoff valve according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a conventional gas cutoff valve. 2... Permanent magnet, 3... Core piece, 4... Guide pipe, 6... Electromagnetic coil, 9... Plunger, 10... Valve rubber (valve).

Claims (1)

[Scope of utility model registration request] A permanent magnet that normally attracts a plunger with a valve at one end through the core piece to open the gas passage, and when an abnormality occurs, excites a magnetic field in the opposite direction to the magnetic field of the permanent magnet to separate the plunger from the core piece and open the gas passage. An electromagnetic coil that closes the plunger, a core piece, a guide pipe with a permanent magnet on the inside and an electromagnetic coil on the outside, and a guide pipe that is installed between the core piece and the yoke to direct magnetic flux from the core piece to the yoke. Gas shutoff valve with bypass section.