JPH0481075B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention has two valve stems inside the valve body,
This invention relates to a dual safety valve that has a function to detect an abnormality when one valve stem does not operate or is delayed in operation.

Prior Art For example, in a control fluid circuit used in a press machine, double control valves are provided for safety.
A safety mechanism that uses a monitor to detect a malfunction in one of the control valves and performs safety operations such as stopping the entire fluid circuit is known, for example, as disclosed in Japanese Patent Laid-Open No. 110885/1985. has been disclosed.
FIG. 5 shows the conventional double safety valve used in this safety mechanism using JIS symbols.

In Fig. 5, from the pressure fluid supply source to the supply pipe P
is connected to the suction port of valve 51 and valve 51', and the operating pipe A connected to the press device is connected to the suction port of valve 51 and valve 51'.
1' discharge port. Valve 51 and valve 5
In this example, reference numeral 1' indicates a three-port solenoid valve having an exhaust port in addition to an intake port and a discharge port. The discharge port is connected to the discharge pipe R.

A monitor 52 has a piston 52a whose both ends are pressed by springs and is held at a neutral position, and a microswitch 52b which detects the movement of the piston 52a. The other end is connected to the valve 5 of the operating pipe A by a conduit 53'.
It is connected to the part connected to the discharge port 1'.

A discharge branch conduit 56 to which an orifice 55 is connected is connected to the conduit 53, and a discharge branch conduit 5 to which an orifice 55' is connected to the conduit 53'.
6' are branch-connected.

In this double type 3 port valve, both valves 51, 5
A monitor 52 detects the pressure difference near the discharge port due to opening and closing of the valve 1', and when a pressure difference occurs, it is recognized as an abnormality.

Problems with the Prior Art When the valves 51 and 51' move in the direction in which their suction ports are connected to their discharge ports,
If one valve does not operate or moves slowly,
Since a pressure difference occurs near the discharge ports of the valves 51, 51', the monitor 52 that detects this pressure difference responds quickly.

However, when the valves 51 and 51' move in the direction in which the discharge port is connected to the discharge port, if one of the valves does not operate or its movement is delayed, the fluid flowing from the discharge port to the discharge port is controlled by the monitor 52. Conduits 53, 53' detected by
Since it is discharged without passing through the port, the pressure difference near the discharge port is small. For this reason, there was a problem that the responsiveness of the monitor 52 was poor.

Means for Solving the Problems The present invention solves the above problems by forming the valve body into a valve body.
A supply port to which fluid is supplied, an outlet port to which an actuator operated by the fluid is connected, a discharge port to discharge the fluid supplied to the actuator side, two valve stems provided inside the valve body, and the supply port. A supply chamber connected to the port, a fluid chamber connected to the outlet port, a discharge chamber connected to the discharge port, and supply openings provided at two locations communicating the supply chamber and the fluid chamber. a discharge opening that communicates the fluid chamber and the discharge chamber and is provided at two locations coaxially with the supply opening; and a discharge opening that is provided at each of the two valve stems;
A first poppet valve body that opens and closes the supply opening, a second poppet valve body that opens and closes the discharge opening, and a pilot valve that is provided for each valve stem and that opens and closes the first and second poppet valves. have,
The first and second poppet valves are such that when the first poppet seats on the valve seat of the supply opening, the second poppet valve opens the valve seat of the discharge opening, and the first poppet valve opens the valve seat of the discharge opening. When opening the valve seat of the discharge opening, the second poppet valve is configured to sit on the valve seat of the discharge opening, and the second poppet valve is configured to be able to detect an abnormality when one valve stem does not operate or is delayed in operation. In the heavy safety valve, a common chamber between the supply opening and the discharge opening, through which fluid flows from the supply chamber to the fluid chamber and fluid flows from the fluid chamber to the discharge chamber; and the common chamber. a first diaphragm disposed on the supply opening side of the common chamber; a second diaphragm disposed on the fluid chamber side of the common chamber and formed to have a smaller aperture than the first diaphragm; A monitor flow path formed between one throttle is provided in each of the two valve stems, and the abnormality is detected based on a pressure difference between the monitor flow paths belonging to each valve stem. The problem was solved with a double safety valve.

Embodiments The structure and operation of the present invention will be explained in detail based on embodiments shown in the drawings.

In FIG. 1, a valve body 1 includes a supply port 2 to which fluid is supplied, an outlet port 3 to which an actuator operated by the fluid (not shown) is connected, and a discharge port 4 to discharge the fluid supplied to the actuator side. is formed. A supply chamber 5 is connected to the supply port 2, and a fluid chamber 6 is connected to the outlet port 3. A discharge chamber 7 is connected to the discharge port 4 .

The supply chamber 5 and the fluid chamber 6 communicate with each other at two locations, the first supply opening 8 and the second supply opening 9, and the fluid chamber 6 and the discharge chamber 7 communicate with each other through the first discharge opening 1.
0 and the second discharge opening 11 are in communication with each other. In this case, the first discharge opening 10 and the second discharge opening 11 are formed to have a larger opening area than the first supply opening 8 and the second supply opening 9. Further, the first supply opening 8 is formed coaxially with the first discharge opening 10, and the second supply opening 9 is formed coaxially with the second discharge opening 11.

The first supply opening 8 and the first discharge opening 10 include
A first valve stem 14 is provided therethrough, and a second supply opening 9 is provided through the second discharge opening 11, and a second valve stem 17 is provided therethrough. The first valve stem 14 and the second valve stem 17 have the same structure, so in order to simplify the explanation, the first valve stem 14 will be described in detail.

The first valve stem 14 has a first poppet valve body 12 seated on the valve seat of the first supply opening 8 and a second poppet valve body 13 seated on the valve seat of the first discharge opening 10.
and is provided. When the first poppet valve body 12 seats on the valve seat of the first supply opening 8, the second poppet valve body 13 opens the first discharge opening 10;
Conversely, the second poppet valve body 13 is connected to the first discharge opening 10.
When seated on the valve seat, the first poppet valve body 12
A first poppet valve body 12 and a second poppet valve body 13 are provided on the first valve stem 14 so as to open the first supply opening 8 .

The first valve stem 14 has a first poppet valve body 12.
A first piston 18 having a larger pressure receiving area and a first valve stem guide rod 19 having a smaller pressure receiving area than the first piston 18 are formed.
8 is slidably guided by the first cylinder part 20 of the main body 1, and the guide rod 19 of the first valve stem 14 is slidably guided by the second cylinder part 21 of the main body 1.

The first cylinder portion 20 has a pilot passage 26
is connected to the outlet port of the first pilot solenoid valve 27. The supply port of the first pilot solenoid valve 27 is connected to the second cylinder portion 21 through a flow path 30.
is communicated with the supply chamber 5 via a flow path 31.

A first common chamber 14A is provided between the first supply opening 8 and the first discharge opening 10, through which the fluid flowing from the supply chamber 5 to the fluid chamber 6 and the fluid flowing from the fluid chamber 6 to the discharge chamber 7 pass. ing. A first throttle 35 is arranged on the first supply opening 8 side of the first common chamber 14A, and a second throttle 37 is arranged on the fluid chamber 6 side of the first common chamber 14A. The second diaphragm 37 is formed so that its aperture amount is smaller than that of the first diaphragm 35.

A first monitor flow path 33 is opened between the first throttle 35 and the first supply opening 8, and the first monitor flow path 33 is connected to a monitor (not shown).

In addition, to explain the correspondence between the first valve stem 14 and the second valve stem 17, the first poppet valve body 12
and the third poppet valve body 15 and the second poppet valve body 13
and the fourth poppet valve body 16, the first piston 18 and the third piston 22, the guide rod 19 and the guide rod 23, the first
The cylinder part 20, the third cylinder part 24, the second
The cylinder part 21 and the fourth cylinder part 25, the pilot flow path 26 and the pilot flow path 28, the first pilot solenoid valve 27 and the second pilot solenoid valve 29,
The flow path 31 and the flow path 32, the first common chamber 14A and the second common chamber 17A, the first aperture 35 and the first aperture 36, the second
Aperture 37, second aperture 38, first monitor channel 33
and the second monitor channel 34 correspond to each other.

Note that one or more second apertures 37 and 38 can be formed. Further, a ring body 39 is formed by integrating the first diaphragm 35 and the second diaphragm 37 or by integrating the first diaphragm 36 and the second diaphragm 38 as shown in FIG. 2, and is attached to the fluid chamber 6. You can also do it like this. Ring body 39
can be constructed with an annular wall of diameter approximately corresponding to the discharge openings 10,11.

FIG. 3 schematically shows this device based on JIS symbols. In FIG. 3, symbol M indicates a monitor.

The operation of this device will be explained below.

Normally, the pilot valves 27 and 29 are in an inoperative state, and the fluid in the first and third cylinder parts 20 and 24 is discharged to the outside, and the fluid in the second and fourth cylinder parts 20 and 24 is discharged to the outside.
1 and 25 are under fluid pressure, the first supply opening 8 and the second supply opening 9 are closed, and the first discharge opening 10 and the second discharge opening 11 are opened.
Therefore, the fluid supply to the fluid chamber 6 is stopped and the fluid chamber 6 communicates with the discharge chamber 7, so that the fluid of the actuator connected to the outlet port 3 is transferred to the discharge port 4.
is discharged from. Fluid, for example air, is discharged from the fluid chamber 6 through the second restriction 37 , 38 into the discharge chamber 7 and into the discharge port 4 . The pressure of the fluid is the second
From the apertures 37 and 38 to the common chambers 14A and 17A, the first
Monitor channels 33, 34 via throttles 35, 36
Detected by The fluid pressure is mainly caused by the second throttle 3
7 and 38, the detected pressure becomes close to the pressure at the discharge port 4.

When the pilot valves 27, 29 are actuated, the pistons 18, 22, which have a larger pressure receiving area than the poppet valve bodies 12, 15, are moved upward from the position shown in FIG. 1 and close the discharge openings 10, 11. , the supply openings 8, 9 are opened. Therefore, the supply chamber 5 communicates with the fluid chamber 6, and the fluid passes from the supply chamber 5 through the supply openings 8, 9, through the first throttles 35, 36, and into the common chamber 14.
A, 17A and the second throttles 37, 38 to the fluid chamber 6, and from the outlet port 3 to the actuator. The pressure drop of the fluid is mainly caused by the first restriction 3
5, 36, the pressure of which is close to that of supply port 2. Therefore, the pressure in both monitor channels 33, 34 is the same when both valve stems 14, 17 are actuated simultaneously and when they are not actuated.

Now, if we look at the case where the first valve stem 14 does not operate for some reason and the second valve stem 17 operates,
The second supply opening 9 and the first discharge opening 10 are opened, the first supply opening 8 and the second discharge opening 11 are closed, and the fluid in the outlet port 3 passes through the second restriction 37 to the first discharge. It passes through the opening 10 and is discharged into the discharge chamber 7. The fluid in the supply chamber 5 is supplied to the second supply opening 9, the first
It flows into the fluid chamber 6 through the throttle 36 and the second throttle 38. Since the flow rate discharged from the first discharge opening 10 is greater than the flow rate flowing in through the second supply opening 9, the fluid supplied to the fluid chamber 6 is further supplied to the second supply opening 9.
It is discharged through the restriction 37 to the first discharge opening 10 and is not supplied to the outlet port 3.

At this time, since the pressure of the fluid supplied from the supply chamber 5 mainly decreases at the first throttle 36, the monitor flow path 34 on the upstream side of the first throttle 36 Detects pressure close to . On the other hand, the pressure in the monitor channel 33 mainly drops at the second throttle 37, and the detected pressure is close to that at the discharge port 4. Therefore, a clear pressure difference is generated between the detected pressures of the monitor channels 33 and 34, and the monitor M can immediately detect an abnormality based on the pressure difference.

The first valve stem 14 is actuated and the second valve stem 17
The case in which the first valve stem is inoperative is exactly the same as the case in which the first valve stem is inactive, so a description thereof will be omitted.

When the movement of one of the two valve stems does not occur or is delayed, the conventional valve also responds quickly if the valve stem moves in the direction of opening the supply opening, but in the case of movement in the direction of closing. Conventional valves are slow. However, in the example shown in Fig. 1, when the normally moving valve stem opens the discharge opening in the closing direction, a second restriction is provided between the discharge opening and the fluid chamber, so the monitor flow path is closed. A pressure close to that of the discharge port is immediately applied. On the other hand, pressure close to the pressure of the supply port is acting on the monitor flow path of a valve stem that does not close due to a malfunction, so as soon as the valve stem starts moving, a pressure difference is created in both monitor flow paths, and the monitor Detect abnormality. Therefore, the response is quick.

In contrast to the example shown in FIG. 1, rings 40 and 41 in which the first throttle is fixed to the valve stems 14 and 17 as shown in FIG.
and the main body 1. That is, the ring 40 and the main body 1 correspond to the first aperture 35.
A diaphragm 42 formed by the first diaphragm 36
A diaphragm 43 formed by the ring 41 and the main body 1 corresponds to the diaphragm 43 . Furthermore, in FIG. 4, the fluid chamber communicating with the first supply opening 8 and the fluid chamber communicating with the second supply opening 9 are separated, and each is a first fluid chamber 44.
and a second fluid chamber 45. First fluid chamber 44
through the second throttle 37' and the second fluid chamber 45.
is connected to the outlet port 3 via a second restriction 38'. The second apertures 37', 38' may have a simple aperture structure different from the example shown in FIG.
In the example shown in FIG. 4, other structures are the same as those in the example shown in FIG. 1, so corresponding parts are given the same reference numerals and explanations will be omitted. The operation is also exactly the same as the example shown in FIG. 1, so the explanation will be omitted.

Effects According to the invention, when the supply opening of one valve stem is open and the supply opening of the other valve stem is closed,
Since the monitor flow path is formed between the supply opening and the first restriction, the fluid pressure of the supply port is input to the monitor flow path of the valve stem with the supply opening open;
The fluid pressure reduced by the second and first throttles is input to the monitor flow path of the valve stem with the supply opening closed. Therefore, in the case of a movement of the valve stem in the direction of opening the supply opening, pressure fluctuations can be sensitively sensed even when one of the valve stems is not activated.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a double safety valve according to the present invention, Fig. 2 is a perspective view of a ring body in which a first throttle and a second throttle are integrally formed, and Fig. 3 is a configuration of a double safety valve according to the present invention. FIG. 4 is a sectional view of a modification of the example shown in FIG. 1, and FIG. 5 is an explanatory diagram of a conventional double safety valve using JIS symbols. 1... Main body, 2... Supply port, 3... Outlet port, 4... Discharge port, 5... Supply chamber, 6, 4
4,45...fluid chamber, 7...discharge chamber, 8,9...
Supply opening, 10, 11...Discharge opening, 12,
13, 15, 16...Poppet valve body, 14, 17
... Valve stem, 14A, 17A ... Common chamber, 3
3, 34...Monitor channel, 35, 36, 42,
43...first aperture, 37, 38, 37', 38'...
...Second aperture.

Claims (1)

[Claims] 1. A supply port formed in the valve body to which fluid is supplied, an outlet port to which an actuator operated by the fluid is connected, a discharge port to discharge the fluid supplied to the actuator side, and the inside of the valve body. two valve stems provided in the valve, a supply chamber connected to the supply port, a fluid chamber connected to the outlet port, and a discharge chamber connected to the discharge port;
Supply openings provided at two locations communicating the supply chamber and the fluid chamber; and discharge openings provided at two locations coaxial with the supply opening communicating the fluid chamber and the discharge chamber. a first poppet valve element provided on each of the two valve stems for opening and closing the supply opening and a second poppet valve element for opening and closing the discharge opening; and a pilot valve that opens and closes the first and second poppet valves, and when the first poppet is seated on the valve seat of the supply opening of the valve, the second poppet valve opens and closes the discharge opening. the second poppet valve is configured to open the valve seat of the opening, and when the first poppet valve opens the valve seat of the supply opening, the second poppet valve seats on the valve seat of the discharge opening; In a double safety valve capable of detecting an abnormality when the valve does not operate or is delayed in operation, between the supply opening and the discharge opening, the fluid flowing from the supply chamber to the fluid chamber and the fluid chamber a common chamber through which fluid flows from to the discharge chamber; a first throttle disposed on the supply opening side of the common chamber; and a throttle amount from the first throttle disposed on the fluid chamber side of the common chamber. is formed into a small second
A restriction and a monitor flow path formed between the supply opening and the first restriction are provided in each of the two valve stems, and the abnormality is determined by the pressure difference in the monitor flow path belonging to each valve stem. A double safety valve characterized by detecting.