JPH0648067B2 - solenoid valve - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a solenoid valve, and more particularly to a stop valve with a solenoid pilot valve (sub valve) used in boilers, chemical reactors and other equipment.

(Prior art) Conventionally, the primary side pressure of the valve is utilized to speed up the valve opening / closing operation,
2. Description of the Related Art A solenoid valve having a structure in which a tight seal is provided in a valve seat portion and a valve opening / closing operation force is reduced is widely used. This type of solenoid valve obtains these effects by controlling the back pressure applied to the main valve body by opening and closing the sub valve.

FIG. 6 shows an example of such a solenoid valve.

As shown in the drawing, when the main valve 81 and the sub valve 91 are closed, the fluid is flowing into the back pressure chamber 88 through the gap between the main valve body 84 and the main valve body guide 87, and the main valve body Primary pressure on the back of 84. This back pressure causes the main valve body 84 to be the main valve seat.
Pressed against 83, holding a tight seal.

When opening the main valve 81, the sub valve 91 is opened via the valve rod 98 by an electromagnetic operating device. The fluid is discharged to the secondary side through the discharge hole 93 of the sub valve body 92 and the sub valve seat 94, and the back pressure decreases.
Therefore, the main valve 81 can be rapidly opened with a small operating force.

When closing the main valve 81, the sub valve 91 is closed by an electromagnetic operating device. As a result, the fluid flows into the back pressure chamber 88 from the primary side of the valve box 82 through the gap between the main valve body 84 and the main valve body guide 87, and the back pressure is applied to the main valve body 84. As a result, the main valve can be closed rapidly with a small operating force.

(Problems to be solved by the invention) By the way, in the above-mentioned conventional solenoid valve, when the main valve 81 is opened, a back pressure is applied from the primary side of the valve box 82 through the gap between the main valve body 84 and the main valve body guide 87. A fluid is supplied to the chamber 88.
However, since the main valve body guide 87 has a function of guiding the main valve body 84, the gap is small and the pressure increase in the back pressure chamber 88 is gentle. On the other hand, an upward force due to the primary pressure is applied to the annular portion 85 on the lower surface of the main valve body 81 outside the surface of the valve seat 83. Then, while the pressure in the back pressure chamber 88 is rising, there is a period during which the downward force due to the back pressure and the upward force due to the annular portion 85 substantially balance, and at this time, due to a slight force imbalance, the main valve Body 84 violently moves up and down. That is, the main valve 81 may hunt. When hunting occurs, the valve body 8
4, valve seat 83, valve stem 98 and other parts are damaged and noise is generated.

(Means for Solving the Problems) A solenoid valve according to the present invention has a main valve body having a sub-valve seat concentric with the main valve seat, a cylindrical shape extending toward the main valve seat and having an upper portion serving as a back pressure chamber. Of the main valve body, a sub valve body that is vertically inserted into a sub valve chamber formed in the main valve body, is connected to the valve stem, and an operating device that drives the valve stem to move up and down. A discharge hole is provided in the cylinder portion of the sub-valve body so as to vertically penetrate the cylinder portion of the sub-valve body and connect the sub-valve body and the back pressure chamber. And
A state in which the main valve body and the main valve body guide are provided with communication holes penetrating in the radial direction thereof so that the primary side of the valve box and the sub valve chamber communicate with each other, and the sub valve is opened The cylindrical portion of the sub-valve closes the communication hole of the main valve.

(Operation) When the main valve and the sub valve are closed, the primary side pressure is applied to the back of the main valve body through the communication holes of the main valve body and the main valve body guide. Due to this back pressure, the main valve body is pressed against the main valve seat, and a tight seal is maintained.

When opening the main valve, when the sub valve is fully opened, the fluid in the back pressure chamber flows out to the secondary side through the discharge hole of the sub valve body and the sub valve seat,
Back pressure is reduced. When the back pressure drops, the main valve opens with a small operating force. At this time, since the communication hole of the main valve body is closed by the raised cylindrical portion of the sub valve body, there is no fluid flow from the primary side into the back pressure chamber, and the back pressure drops rapidly. As a result, the upward force due to the primary pressure applied to the annular portion on the lower surface of the main valve body becomes larger than the downward force due to the back pressure in an instant, and the main valve rapidly fully opens. Therefore, valve hunting does not occur.

When the main valve is closed, when the sub valve is closed, fluid flows from the primary side of the valve box into the back pressure chamber through the communication holes of the main valve body and the main valve body guide, and back pressure is applied to the main valve body. And the main valve closes. Since the fluid flows into the back pressure chamber through the communication hole and the discharge hole as described above, the back pressure applied to the main valve body rapidly increases. Therefore, the main valve is closed at once and no hunting occurs.

(Embodiment) FIG. 1 shows an example of a solenoid valve according to the present invention, and is a longitudinal sectional view of the solenoid valve as a whole. The solenoid valve is roughly divided into a main valve 1 and an operating device 45. The main valve 1 is composed of a valve box 2, a lid 8, a main valve body 11, a main valve body guide 21, a valve rod 41 and the like, and includes a sub valve 30.

As shown in FIG. 1, the main valve body 11 is cup-shaped,
The inside is the sub valve chamber 12 of the sub valve 30. A sub valve opening 13 is provided at the bottom of the main valve body 11 concentrically with the main valve opening 5.
The upper edge of the main valve opening 5 serves as a main valve seat 6. The upper edge of the sub valve opening 13 is a sub valve seat 14. Further, the peripheral wall 15 of the main valve body 11 is provided with a communication hole 16 which penetrates the peripheral wall 15 in the radial direction.

In the valve box 2, a cylindrical main valve body guide 21 extends toward the main valve seat 6, and the main valve body guide 21 is located above the valve box 2
And is fixed by the lid 8. A back pressure chamber 25 is provided inside the main valve body guide 21 above the main valve body 11. Further, the reverse seat with which the reverse seat surface 42 of the valve rod 41 is in contact with the upper part of the main valve body guide 21.
27 are provided. The peripheral wall 22 of the main valve body guide 21 is provided with a communication hole 23 penetrating in the radial direction similarly to the main valve body 11, and the communication holes 16 and 23 of the main valve body 11 and the main valve body guide 21 are continuous. The primary side 3 of the valve box 2 and the auxiliary valve chamber 12 are connected to each other. The communication holes 16 and 23 of the main valve body 11 and the main valve body guide 21 are
The back pressure chamber 25 has a sufficiently large diameter so that the primary side fluid can be rapidly supplied. Furthermore, both communication holes 16, 23
Are always in communication regardless of whether the main valve 1 is in the fully open position or in the fully closed position.

The sub-valve body 31 of the sub-valve 30 has a valve body portion 33 formed at the lower end of a cylindrical portion 32, and the valve body portion 33 is a sub-valve seat provided on the main valve body 11.
Sit on 14 and seal the fluid. Further, a discharge hole 35 is formed in the cylindrical portion 32 of the sub-valve body 31 so as to vertically penetrate therethrough. The discharge port 35 connects the sub valve chamber 12 and the back pressure chamber 25. The sub valve body 31 is connected to the lower end of the valve rod 41 via a pin 43, and moves up and down in the sub valve chamber 12.

A disc nut 37 is attached to the upper portion of the main valve body 11, and the disc nut 37 limits the lift of the sub valve body 31. With the sub-valve 30 fully open, the top surface of the cylindrical portion 32 of the sub-valve body 31 is in close contact with the bottom surface of the disc nut 37, and the communication hole of the main valve body 11 is formed.
Block 16 In addition, the disc nut 37 has a discharge hole for the auxiliary valve body 31.
A through hole 38 is provided so as to communicate with 35, and the auxiliary valve chamber 12 and the back pressure chamber are formed by the discharge hole 35 and the through hole 38.
I'm in contact with 25.

A spring case 46 containing a coil spring 47 is fixed in the lid 8. The coil spring 47 is attached to the top of the spring case 46 and the valve rod 41.
Is compressed between a spring seat 48 attached to the. Therefore, the spring force acts to constantly push down the main valve body 11 via the valve rod 41 and the sub valve body 31.

A solenoid 51 is attached to the upper flange 9 of the lid 8 about the valve rod axis. Further, an annular permanent magnet 53 is attached adjacent to the top of the solenoid 51. The upper and lower sides of the permanent magnet 53 are magnetic poles. A cylindrical iron core 55 penetrates through the solenoid 51 and the permanent magnet 53. The lower end of the iron core 55 is fixed to the lid 8,
The top is closed by a cap 56. The lower half of the iron core 55 is connected to the plunger chamber 57, and the plunger 61 is housed therein. The plunger 61 is fixed to the valve rod 41 by a pin 62. A DC power source and an operation switch (neither of which is shown) are connected to the solenoid 51.

The solenoid 51 and the permanent magnet 53 are housed in a housing 65. At the top of the housing 65, a pair of proximity switches 68 are arranged vertically spaced from each other. In addition, the valve lift detection piece
69 is installed. The proximity switch 68 detects whether the valve is fully open or fully closed depending on the position of the detection piece 69.

Here, the operation of the solenoid valve configured as described above will be described.

FIG. 2 shows a state in which the main valve 1 and the sub valve 30 are closed. In this state, the fluid enters the back pressure chamber 25 from the primary side 3 of the valve box 2 through the communication holes 16 and 23 of the main valve body 11 and the main valve body guide 21, and the through hole 38 of the disc nut 37. At this time, the solenoid 51 is deenergized. The main valve body 11 is pressed against the main valve seat 6 by the pressure of this fluid, that is, the back pressure, and a tight seal is maintained.

When the main valve 1 is opened, when the solenoid 51 is biased, the plunger 61 rises against the force of the coil spring 47, the valve rod 41 rises, and the sub valve 30 is fully opened. As a result, as shown in FIG. 3, the fluid in the back pressure chamber 25 flows through the through hole 38 of the disc nut 37 and the sub valve body 31.
Through the discharge hole 35 and the auxiliary valve opening 13 to the secondary side 4, and the back pressure is reduced. When the back pressure decreases, the main valve 1 opens with a small operating force. At this time, since the communication hole 16 of the main valve body 11 is closed by the raised cylindrical portion 32 of the sub-valve body 31, no fluid flows from the primary side 3 into the back pressure chamber 25, and the back pressure rapidly increases. Go down. Therefore, the upward force due to the primary pressure applied to the annular portion 18 on the lower surface of the main valve body 11 becomes larger than the downward force due to the back pressure, and the main valve 1 is rapidly fully opened. That is, valve hunting does not occur.

When the main valve 1 is fully opened, the top surface of the plunger 61 is in close contact with the attraction surface 58 of the iron core 55, so that the main valve 1 can be fully opened only by the attractive force of the permanent magnet 53. Therefore, when the proximity switch 68 detects that the main valve 1 is fully opened, the solenoid 51 is automatically deenergized. FIG. 4 shows a state where the main valve 1 is fully opened.

When closing the main valve 1, when the solenoid 51 is biased in the opposite direction so as to cancel the attraction force of the permanent magnet 53, the force of the coil spring 47 overcomes the attraction force of the permanent magnet 53 and the valve rod 41 descends. As a result, the sub valve 30 is closed, and the fluid flows into the back pressure chamber 25 from the primary side 3 of the valve box 2 through the communication holes 16 and 23 of the main valve body 11 and the main valve body guide 21, and the through hole 38 of the disc nut 37. However, back pressure is applied to the main valve body 11. Then, the main valve 1 is closed. Since the fluid flows into the back pressure chamber 25 through the communication holes 16 and 23 and the through hole 38 as described above, the back pressure applied to the main valve body 11 rapidly increases. Therefore, the main valve 1 is closed at once and no hunting occurs.

In this embodiment, the top of the iron core 55 is capped as described above.
Since it is blocked with 56, the hot fluid that has flowed in is iron core 55
The convection that occurs inside is small. Therefore, overheating of the solenoid 51 is prevented. Further, when the main valve 1 is fully opened, the reverse seat 27 is in contact with the reverse seat surface 42 of the valve rod 41, so that the hot fluid is prevented from flowing into the iron core 55. Further, since the solenoid 51 is deenergized when the main valve 1 is fully opened, there is no fear that the coil will burn due to long-time energization.

FIG. 5 shows another embodiment of the present invention. The same parts as those in the above embodiment are designated by the same reference numerals, and the description of these parts will be omitted.

A peripheral portion 74 where the communication hole 73 opens in the sub valve chamber 72 is inclined downward. On the other hand, the top of the cylindrical portion 76 of the sub valve body 75 is a similarly closed closing portion 77, and the closing portion 77 closes the opening of the communication hole 73 of the main valve body 71. In this structure the closure
The wedge action of 77 tightly closes the opening of the communication hole 73.

The present invention is not limited to the above embodiment, and for example, the coil spring may be set so as to push up the valve rod, that is, open the sub valve.

Further, in the portion where the valve rod penetrates the partition between the back pressure chamber and the coil spring chamber, by making the gap between the valve rod and the through hole small, the inflow of fluid into the coil spring chamber can be suppressed. As a result, the temperature rise of the coil spring and other parts can be prevented, and in this case, the reverse seat can be omitted.

(Effects of the Invention) In the solenoid valve of the present invention, since hunting does not occur when opening and closing the valve, the hunting does not damage the valve seat, the valve body and other parts, and does not generate noise.

[Brief description of drawings]

FIG. 1 shows an example of a solenoid valve according to the present invention, and is a longitudinal sectional view of the solenoid valve as a whole. FIGS. 2 to 4 are operation explanatory views of the solenoid valve. FIG. 5 shows another embodiment of the present invention. FIG. 5 is a longitudinal sectional view of a main portion of a solenoid valve, and FIG. 6 is a vertical sectional view of a main portion of a conventional solenoid valve. 1 ... Main valve, 2 ... Valve box, 8 ... Lid, 11 ... Main valve body,
12 …… Sub valve chamber, 14 …… Sub valve seat, 15 …… Peripheral wall, 16 …… Communication hole, 21 …… Main valve disc guide, 22 …… Peripheral wall, 23 …… Communication hole,
25 …… back pressure chamber, 30 …… sub valve, 31 …… sub valve body, 32 …… cylinder part, 35 …… discharge hole, 37 …… disc nut, 41 …… valve rod,
45 …… Operating device, 81 …… Main valve, 84 …… Main valve disc, 87 …… Main valve disc guide, 88 …… Back pressure chamber, 91 …… Sub valve, 92 …… Sub valve disc.

Claims (1)

[Claims] 1. A main valve body having a sub-valve seat concentric with the main valve seat, a cylindrical main valve body guide extending toward the main valve seat and having an upper portion as a back pressure chamber, and formed in the main valve body. A sub-valve body vertically inserted into the sub-valve chamber and connected to the valve stem, and an operating device for raising and lowering the valve stem. In a solenoid valve having a discharge hole that connects a seat and a back pressure chamber in a cylindrical portion of a sub-valve body, the main valve body and the main valve such that the primary side of the valve box and the sub-valve chamber communicate with each other. Communication holes penetrating in the radial direction are provided in the peripheral wall of the body guide, and the cylinder portion of the sub-valve body closes the communication hole of the main valve body when the sub-valve is opened. Solenoid valve.