JPS6243369Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pressure reducing valve with a built-in safety valve on the secondary side.

Recently, air pressure is used for air brakes, lock brakes, air suspensions, etc. in large trucks, buses, etc., and the working pressures are (6 to 8) Kg/cm ² and (3 to 4) Kg/cm, respectively. ^2,8Kg /
cm ² . Therefore, in this case, the air source is set at a maximum pressure of 8 kg/cm ² suitable for air suspension, and when used for other purposes, the pressure is reduced to an appropriate pressure using a pressure reducing valve.

The one shown in Figure 1 is a conventional pressure reducing valve, where 1 is a valve box, 2 is a primary side connection port, 3 is a secondary side connection port, 4 is a partition wall, 5 is an opening, 6 is a valve seat, and 8 is a movable valve. A diaphragm serves as a wall, 9 is a spring, 10 is a valve, and 11 is a valve body. In FIG. 2, A _v is the area of the opening 5 of the partition wall, A _d is the area of the diaphragm 8, and p _i is the primary fluid pressure. , p _p is the secondary fluid pressure.

In FIG. 2, when the primary and secondary fluid pressures p _i and p _p act on the valve body 11, the valve body flows through the vertical groove 11A cut into the sliding surface of the valve body 11 on the primary side. Bottom surface 1
The force p _i A _v acts upward from 1B, and also on the secondary side via the surface of the diaphragm 8, p _p (A _d −A
_v ) acts upward, and the resultant force of these forces acting on the valve body 11 is F _a . On the other hand, a downward pressing force F _s is exerted on the valve body 11 by the spring 9, and the following three cases can be considered as the relationship between these forces.

p _i A _v +p _p (A _d −A _v )=F _a 〓F _s ∴p _p 〓F _s −p _i A _v /A _d −A _v =K In the above equation, F _a <F _s, that is, p _p < At K (specified value), the valve 10 continues to open. Therefore, when the secondary pressure p _p is less than the specified value K, high-pressure fluid flows from the primary side to the secondary side, and the secondary pressure p _p gradually increases until it reaches the specified value K, which is lower than the primary pressure p _i . Valve 10 closes and the pressure reducing valve stops operating. In addition, the pressure difference p _i −p _p between the primary and secondary sides is as follows.

p _i - _{p p} = p _i -F _s - p _i A _v /A _d - A _v = p _i
A _d −F _s /A _d −A _v Therefore, by appropriately selecting the diaphragm area A _d , the opening area A _v , and the spring strength F _{s ,} the outlet pressure K can be selected in any manner.

Next, after a while, the fluid pressure on the secondary side p _p
falls below the specified value K, F _a <F _s and valve 10
opens, the primary fluid is supplied, and the secondary fluid pressure p
_p increases and reaches the specified value K. This operation is repeated to maintain the secondary pressure at the specified value K. However, if the secondary fluid pressure p _p rises above the specified value K for some reason, the primary and secondary fluid pressures against the valve body 11 The resultant force F _a due to p _i and p _p overcomes the spring force F _s . That is, when F _a > F _s , the valve body 11 is pushed upward and the valve 10 continues to close, and there is no action to return the secondary fluid pressure p _p to the specified value K, and in some cases, the secondary fluid pressure The pressure p _p rose further, and there were concerns that the related machinery on the secondary side would eventually break down. To prevent this, a separate safety valve was often installed on the secondary side outside the safety valve.

The purpose of the present invention is to eliminate the drawbacks of the conventional devices mentioned above, and to save labor on piping work required when using a separate safety valve on the secondary side by incorporating a safety valve inside the pressure reducing valve. To provide a pressure reducing valve.

An embodiment of the pressure reducing valve according to the present invention will be described below with reference to FIG.

Here, the same or equivalent components as those of the conventional device will be described using the same reference numerals.

In FIG. 3, 1 is a valve box, which has a primary side connection port 2, a secondary side connection port 3, and a partition wall 4 that partitions the primary side and the secondary side, and the partition wall 4 has an opening 5. A valve seat 6 is provided on the lower edge of the opening 5. A diaphragm 8 that responds to the fluid pressure on the secondary side is equipped with a movable valve seat 7 that communicates with the outside air above the opening 5.
The diaphragm 8 is pressed downward by a spring 9, and the valve seat 6 formed on the lower surface of the opening 5 and the movable valve seat 7 to which the diaphragm 8 is attached are
Two valves 10A, 10 facing each other from below
The valve body 11 having a diameter B is slidably supported by the valve body 1 at its lower part, and a vertical groove 11A is provided in the sliding part of the valve body 11, and the lower surface 11B of the valve body 11 is connected to the primary side connection port 2. It communicates with

The operation of the embodiment described above will be explained with reference to FIGS. 2 and 3.

Primary and secondary fluid pressures p _i and p _p act on the valve body 11, and if A _v is the area of the partition wall opening 5 and A _d is the area of the diaphragm 8, then on the primary side, the sliding surface of the valve body 11 is The valve body 11 passes through the cut vertical groove 11A.
The force p _i A _v acts upward from the lower surface 11B of the diaphragm 8, and furthermore, on the secondary side, the force p _p (A _d
−A _v ) acts upward and the resultant force of these forces is F _a
It is. On the other hand, a downward pressing force F _s acts on the valve body 11 from the spring 9 via the diaphragm 8, and the following three cases can be considered as the relationship between these forces.

p _i A _v +p _p (A _d −A _v )=F _a 〓F _s ∴p _p 〓F _s − p _i A _v /A _d −A _v =K In the above equation, F _a <F _s and p _p < When K (specified value), the valve 10 continues to open and high pressure fluid flows in from the primary side.
The secondary fluid pressure p _p gradually increases, and when it reaches a specified value K lower than the primary side pressure p _i , the valve 10 closes and the operation of the pressure reducing valve stops.

However, if the secondary fluid pressure p _p falls below the specified value K after a while, the pressure reducing valve opens again, and this operation is repeated to keep the secondary fluid pressure p _p always at the specified value K. do.

Next, if the secondary fluid pressure p _p rises above the specified value K for some reason, the primary and secondary fluid pressures p _i , p _p
The resultant force F _a becomes larger than the spring force F _s , and the diaphragm 8 to which the movable valve seat 7 is attached moves upward, opening the valve 10B, releasing the excess pressure on the secondary side, and reducing the secondary side pressure p. The operation is performed so that _p becomes the specified value K.

According to the present invention, the diaphragm and the upper part of the valve body were conventionally integrated on the secondary side, but the diaphragm and the valve body are separated, a movable valve seat is attached to the diaphragm, and a valve is mounted to oppose the movable valve seat from below. Since a new valve is installed on the valve body, even if the secondary fluid pressure attempts to rise above the specified value K, this newly installed valve will open, allowing the excess pressure to escape and return to the specified value, eliminating the risk of occurrence due to increased pressure. Failure of secondary side equipment can be prevented.

Furthermore, if this pressure reducing valve is used, since a safety valve is built-in, the piping work that would be required when a separate safety valve is used on the secondary side can be saved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional pressure reducing valve, FIG. 2 is an explanatory diagram of the operation of a conventional pressure reducing valve, and FIG. 3 is a sectional view of a pressure reducing valve according to the present invention. 1... Valve box, 2... Primary side connection port, 3... Secondary side connection port, 4... Partition wall, 5... Opening, 6... Valve seat, 7... Movable valve seat, 8... Movable wall (diaphragm), 9... Spring, 10A, 10B... Valve, 11
... Valve body.

Claims (1)

[Scope of utility model registration request] A valve box 1 is provided with a partition wall 4 having an opening 5 with a valve seat 6 on the lower surface between the primary connection port 2 and the secondary connection port 3, and a movable valve body 1 that communicates with the outside air above the opening 5. A movable wall 8 to which the valve seat 7 is attached and responds to the fluid pressure on the secondary side, a spring 9 that presses the movable wall 8 from above, a valve seat 6 formed in the opening 5 and a movable valve seat 7 formed in the movable wall 8. A pressure reducing valve comprises two valve parts 10A and 10B which are opposed from below, respectively, and a valve body 11 which is slidably supported by a valve body 1 below the valve body 1 and responds to the primary fluid pressure.