JPS6146209A - Automatic changeover valve for filter - Google Patents

Abstract

PURPOSE:To move smoothly and easily a main valve body in changing over the valve for backwashing by providing a through-hole which is opened and closed by an auxiliary valve body at the inside of the main valve body of a changeover valve on the untreated water side, and passing the untreated water through said main valve body. CONSTITUTION:An automatic changeover valve body 1 for filters consists of valves V and V' for communicating appropriately and alternately inlets 4 and 4', outlets and inlets 5 and 5', and outlet 6 and 6' which are provided respectively to cylindrical bodies 2 and 2' on the untreated water side and the backwashing side by sliding main valve bodies 8 and 8' which are connected unitedly with a reciprocating shift 7 through the inside of the cylindrical bodies 2 and 2'. In said main valve body 1, a through-hole 14, passing through the main valve body 8, is formed at the inside of the main valve body 8 on the untreated water side, and an auxiliary valve body 12 for opening and closing the through-hole 14 is provided to the end part on the untreated water side of said reciprocating shaft 7 inserted into the through-hole 14. A valve moving device 16 is further furnished to the main valve body 8 through a guide 17 for sliding and guiding the auxiliary valve body 12, and the movement of the reciprocating shaft 7 to the untreated water side is transmitted to the main valve body 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an automatic switching valve for a filter. In the filtration machine using the automatic switching valve material described in Japanese Patent Publication No. 54-26027, which was previously invented by the present inventor, even when the filtration process is stopped, the main valve body on the raw water side in the filtration tank and automatic switching valve has high Closing pressure may be applied. For example, when filtered water is pumped directly to an elevated tank for water supply, when a filter is installed in a basement and a receiving tank for filtered water is installed on a high floor or rooftop, when a tall activated carbon filtration tower or a This happens when the filtration tank, filtration basin, or filtration layer of a filtration machine becomes clogged with a large amount of suspended matter, and even if the filtration layer pump is stopped, water permeability is lost and the pressurized state persists forever. In such cases, even if you stop the filtration pump for the purpose of backwashing the filtration layer and start the backwash pump after a certain timing, the main valve body may not move and the valve may not be switched. . This is because the high water head pressure acts in the direction of closing the main valve body on the raw water side, and the discharge pressure generated by the rotation of the backwash pump runner is smaller than the former, and the main valve body rebounds against this pressing force. It is impossible to push back. In such a situation, the inside of the filtration tank becomes a sealed container, and the discharge pressure of the backwash pump also acts on the surface of the main valve body on the raw water side.
The force relationship between the two is balanced and the valve body cannot move at all. Furthermore, when a high head backwashing pump is used, the discharge pressure rises to the maximum and then suddenly switches, resulting in severe impact noise and vibration.

The present invention solves all these drawbacks. That is, in the present invention, the main valve body 8.8', which slides back and forth inside a cylindrical body 2.2' having three openings, an inlet, an outlet, and an outlet, is changed in position and stopped at a predetermined position. The two valves V and V' that enable switching between communication with the inlet/outlet and communication between the inlet/outlet and the outlet are installed so that the sliding direction of the main valve body matches (separately or integrally provided, Valve VSV
'In a switching valve in which the main valve bodies are connected by a reciprocating shaft that slidably passes through two opposing partition walls, a through hole 14 that passes through the main valve body 8 is provided inside the main valve body 8 on the raw water side. form,
The reciprocating shaft 7 is inserted into the through hole 14, and the auxiliary valve body 12 for opening and closing the through hole 14 is provided at the raw water side end of the reciprocating shaft 7, and the raw water side end of the reciprocating shaft 7 is provided at the tip of the main valve body 8 on the raw water side. This relates to an automatic switching valve for a filter, which is provided with a valve moving tool 16 that transmits movement to the main valve body 8.

The drawings will be explained in detail. Figure 1 is a schematic cross-sectional view of an automatic switching valve, Figures 2, 3, and 4 are detailed partial cross-sectional views showing the operation of the valve, and Figure 5 is a schematic cross-sectional view of a filter showing an embodiment. 1. 1 in FIG. 1 is the automatic switching valve main body according to the present invention. 2 is a cylindrical body on the raw water side, and 2' is a cylindrical body on the backwash side, which is made of metal, synthetic resin, or a composite thereof. 3 is a sealed bearing made of metal, synthetic resin, or a composite thereof. 4 is the raw water side inlet, 4' is the backwash side inlet, 5 is the raw water side inlet, 5' is the backwash side inlet, 6 is the raw water side outlet,
6' is a backwash side outlet. 7 is a reciprocating shaft made of metal or synthetic resin, and is preferably lightweight and has a smooth surface for sliding movement. 8 is the main valve body on the raw water side, 8I is the main valve body on the backwash side, and the position shown by the solid line is during filtration.
The position indicated by the dotted line is during backwashing. The material of the valve body is metal, synthetic resin, or a composite thereof. The force with which this valve body operates is determined by the weight of this valve body and the reciprocating shaft 7.
Since it is the value obtained by adding the weight of , multiplied by the coefficient of friction,
In order to make this valve body easy to operate, it is desirable that it be lightweight. 9 is an elastic body on the raw water side, and 9' is an elastic body on the backwash side.

9 is fixed to the main valve body 8, and 9' is fixed to the main valve body 8'. The material of the elastic body is made of synthetic rubber such as neoprene, Paiton, Hiker (registered trademark), natural rubber, or synthetic resin, and it tightly adheres to the other side to form a water seal.

The hardness of the elastic body is preferably around 60 degrees. If it is too soft with a hardness of about 20 degrees, it is undesirable because it may sink into the valve seat 10 side and cause abnormal deformation when high water pressure is applied during filtration, and may cause malfunction due to abnormal resistance during switching. If the valve bodies 8 and 8' are made of a soft or elastic body, the elastic body 9.9' can be omitted. 10 is the raw water side valve seat, 1
0' is a backwash side valve seat, and elastic bodies 9 and 9' are in close contact with each other to seal water. Since 9.9' is an elastic body, 10.10' is preferably a rigid body. 11 is the seal ring and 0-IJ song is V-
A ring is used.

The material should be neoprene, Piton, Hiker Rubber (registered trademark), etc., and should be water resistant, chemical resistant, oil resistant, weather resistant, and not lose its elasticity even at low temperatures.

An auxiliary valve body 12 is made of metal, synthetic resin, or a composite thereof, and is fixed to one end of the reciprocating shaft 7. 13 is an elastic material made of neoprene, pyton, hiker rubber (registered trademark)
It is made of an elastic material such as synthetic rubber, natural rubber, or synthetic resin, and when it is fixed to the auxiliary valve body 12 and comes into close contact with the main valve body 8, it seals water. If the entire auxiliary valve body 12 is made of an elastic or soft material, 13 can be omitted. A through hole 14 is provided in the center of the main valve body 8 and passes through the main valve body. Reference numeral 15 denotes a bearing portion, which is a part of the main valve body 8. A reciprocating shaft 7 is slidably inserted through the central hole, and the main valve body 8 is supported with respect to the shaft 7. A valve moving device 16 is made of metal, synthetic resin, or a composite thereof, and is integrated with the main valve body 8 and transmits the movement of the shaft 7 to the main valve body 8 via the auxiliary valve body 12. 17 is a guide made of metal, synthetic resin, or a composite thereof;
A hollow cylinder having one or more rod-like bodies or many holes is used, and one end is fixed to the main valve body 8 and the other end is the valve moving tool 1.
6 is fixed. The inside of the guide 17 is the auxiliary valve body 12
When the main valve body 8 moves, it is slidably fitted to the outer circumferential surface of the
It serves to maintain a correct posture parallel to the reciprocating axis 7. The guide 17 also serves as a support for the valve moving tool 16 with respect to the main valve body 8.

FIG. 2 shows a detailed partial cross-sectional view of the cylindrical body 2 shown in FIG. 1, and the reference numerals are the same as in FIG. 25 is the raw/drainage pipe,
26 is a backwash water discharge pipe, and the details of both 25 and 26 are shown in the embodiment shown in FIG.

FIG. 3 shows the state when the auxiliary valve body 12 is opened from the state shown in FIG. 2, which is the first stage of operation. The arrow → indicates the flow of water, and the arrow ← indicates the direction in which the reciprocating shaft 7 moves.

FIG. 4 shows a state in which the main valve body 8 moves further from the state shown in FIG. 3, which is the second stage of operation.

FIG. 5 is a schematic cross-sectional view of a filter equipped with the automatic switching valve 1 according to the embodiment, and shows a tall filter such as an activated carbon filtration tower. 18 is a filtration tank, 19 is a filtration layer made of natural or artificial filter media such as silica sand, granular activated carbon, anthracite, zeolite, various mineral particles, chamotte, or synthetic resin particles,
Synthetic fibers and the like are used singly or in multiple layers depending on various filtration purposes. 20 is a filter layer pump, and 21 is a backwashing pump, each of which is a land-based centrifugal pump, an axial flow pump, a mixed flow pump, a submersible pump, or the like. 22 is an elevated water tank from which water is supplied to various locations. Reference numeral 23 denotes a washing drainage basin, and 24 denotes a raw water pipe through which raw water, which is water to be filtered, is sent toward the filter.

25 is a raw/drainage pipe through which raw water flows upward and backwash wastewater flows downward. Reference numeral 26 indicates a backwash water discharge pipe, and 27 indicates a water purification pipe. The filtered water flows from the lower part of the filtration tank 18 toward the automatic switching valve 1, and the backwash water flows in opposite directions from the switching valve 1 to the lower part of the filtration tank 18. flows. n is filtrate delivery pipe, 2
9 is a water pipe for backwashing, and 30 is an exhaust valve that exhausts the air in the filtration tank 18 and allows air to flow into the tank 18 as needed. 31 is a check valve to prevent water from flowing back toward the pump 20 in the pipes 24 and 25 when the pump 20 is stopped.

Reference numeral 32 is a check valve that, when the pump 21 is stopped, opens the pipe 27.
This is to prevent the water in 29 from flowing back toward the pump 21. Reference numeral 33 denotes a check valve, which is provided in a part of the filtered water delivery pipe 28. This check valve operates when the filtration layer pump 20 is once stopped.
Water in the tube 28 is prevented from flowing back toward the filtration tank 18 in the opposite direction of filtration. The reason is that it flows backwards.
This is because the fixed bed of the filtration layer 19 may be loosened, and the accuracy of the filtrate may be temporarily lowered when the filtration layer pump 20 is started next time. If the top of the pipe 28 is equal to or lower than the top of the filtration tank, no backflow phenomenon will occur and the check valve 33 is not required. However, in this case, when the pump 20 stops, there is a risk that a siphon phenomenon will occur and the water in the tank 18 will be discharged, so a siphon cut valve for sucking air is installed at the top of the pipe 28. 34 is the opening and the raw/drainage pipe 25
is opened at the upper part of the filtration tank 18, and serves as an outlet for raw water during filtration, and serves as an inlet for backwashing the filtration layer 19 and flowing into the pipe 25 during backwashing. Opening 34
The distance between the top surface of the filter layer 19 and the top surface of the filter layer 19 is called the sand water depth.
The standard is 0 to 60 yen. 35 is a raw water room. H
t represents the static water head applied to the main valve body 8 when the filtration tank 18 is full, and HI! is the static water head applied to the main valve body 8 when pumping water to the elevated water tank 22, and Hi is the automatic switching valve 1.
This is the hydrostatic head applied to the pump 21.

Next, the operation and function of the automatic switching valve according to the present invention will be explained in detail using the drawings. In Figures 1 and 5, the positions of the main valve bodies 8 and 8' indicated by solid lines represent the states during filtration and when filtration is stopped, and the positions indicated by dotted lines indicate the states during backwashing and when backwashing is stopped. This shows the state immediately after stopping. The conditions under which the valve bodies 8 and 8' can be moved from the filtration position shown by the solid line to the backwash position shown by the dotted line by starting the backwash pump 21 will be described.

The surface of the main valve body 8 on the raw water side that receives water pressure (hereinafter referred to as the pressure receiving surface)
Let be Acd and the water pressure be Hky/ci.

Assuming that the pressure receiving surface of the main valve body 8' on the backwash side is A'cIi, and the water pressure at the time of starting the backwash pump 21 is Hp by/ctA, the moving force is at least 'Hp・A'>H-A+reciprocating shaft. The sliding resistance is 7. Describing the relationship between A and A', in the case of a pressure filter such as the filtration tank 18 shown in FIG. 5, A=A'.
It is. In the case of an open type rapid filtration basin, A >A'. The size of area A is determined by the flow resistance value of the backwash flow rate. This is because a pressurized type can easily obtain a high head, but an open type cannot obtain a high head because backwashing water is discharged using a natural head. The next condition is that if there is no water flow in the pipe from the backwashing pump 5, no pressure will be generated to push the main valve body 8' (1). The gap between the inner wall surface of the pump 21 and the inner wall surface is about 2 to 4 meters for large diameter pumps and 1 to 2 meters for small diameter pumps, and water can flow through the gap.The water that flows through the gap when the pump 21 is activated is
It flows into the filtration tank 18 or into the filtrate delivery pipe 28. If water cannot flow into either of the two, that is, if there is no place for water to escape, the water in the pipe 29 will not flow, and no energy will be obtained to push the valve body 8'. 1 in tube 29
Even if water flows, the main valve body 8' may remain stationary without moving. In this state, if the lift of the backwash pump 21 is sufficiently high, water flows through the gap between the outer peripheral surface of the main valve body 8' and the inner wall of the cylindrical body 2', and rises in the pipe 28 from the outlet 6. Then, the check valve 33 is pushed up and a large amount of water is discharged from the mouth at the tip of the pipe 28. This state occurs because the force pushing the main valve body 8' to the left is smaller than the force acting in the direction of closing the main valve body 8. This force in the closing direction is equal to unit area pressure x pressure receiving area, so if the valve body 8 has a small pressure receiving area, the force acting in the closing direction will be small, whereas the force trying to push it open will be large. Of course it's easy to open (
Become. On the other hand, in view of the flow rate required for backwashing, it is not permissible to make the main valve body 8 extremely smaller than 8'. The main company proposed that the main valve body 8 be provided with an auxiliary valve body 12 in the central part of the main valve body 8, as shown in FIGS. Auxiliary valve body 1
As shown in the drawing, the pressure-receiving area of No. 2 is small (because it is small, the force required to open it is small and it can be easily opened by the pushing force of the main valve body 8'. When the auxiliary valve body 12 opens, the main valve body 8
Water discharge begins through the through hole 14 passing through. When flowing water occurs, water pressure in the opposite direction acts on the back surface of the auxiliary valve body 12 and the back surface of the main valve body 8, that is, on the right side, so the force that acts in the direction of closing the main valve body 8, that is, in the right direction, decreases. It is.

Furthermore, the pressure receiving area of the next main valve body 8 becomes smaller by the surface area that the auxiliary valve body 12 received pressure. Therefore, the force acting on the main valve body 8 in the closing direction becomes small, and the main valve body 8 can be easily opened (moved in the direction) by the pushing force of the main valve body 8'.

Next, the operation and function of the valve bodies 8 and 8' will be explained in detail using FIGS. 1 to 4. FIG. 1 shows a filtration state in which the main valve body 8 is closed. The raw water side elastic body 9 is in close contact with the raw water side valve seat 10, and the elastic body 13, which is a part of the auxiliary valve body 12, is in close contact with the main valve body No. 8 to seal the through hole 14 with water. When filtration is being performed, raw water enters the raw water side cylindrical body 2 from the raw water side port 4, exits from the raw water side entrance 5, and is sent to the filter. The filtered water enters the backwash side cylindrical body 2' through the backwash side inlet/outlet 5', exits through the backwash side outlet 6', and is sent to a target location. FIG. 2 shows an enlarged view of the main valve body 8 in the state shown in FIG. When switching from filtration to backwashing, first stop feeding raw water from the raw water side inlet 4 shown in Fig. 1, lower the water pressure applied to the main valve body 8 on the raw water side to the lowest level, and then switch to the backwash side inlet 4'. Send more water for backwashing. This water flow pressurizes the pressure receiving surface on the right side of the main valve body 8' on the backwash side and pushes the main valve body 8' to the left, and the reciprocating shaft 7 moves to the left to open the auxiliary valve body 12. FIG. 3 shows the operation of this first stage of switching. The left side of the auxiliary valve body 12 contacts the right side of the valve moving tool 16 fixed to the main valve body 8 via the guide 17, and the valve body 12 stops opening. The distance between the right side of the elastic body 13 fixed to the auxiliary valve body 12 and the surface of the main valve body 8 that seals the through hole 14 is such that the outer diameter of the auxiliary valve body 12 is 50 mm.
When the diameter is 100, the appropriate position is 3C11, and when the outer diameter is 100, the appropriate position is 51. The arrow indicates the flow of water when the auxiliary valve body 12 opens →
It is shown in The water in the pipe 25 is transferred to the raw water side inlet/outlet 5 → the inside of the raw water side cylindrical body 2 → the gap between the elastic body 13 and the main valve body 8 → the through hole 1
4→Right side of main valve body 8÷Lower for raw water side 6→Pipe 26.

In FIG. 4, the auxiliary valve body 12 pushes the valve moving tool 16, and the valve moving tool 16 pulls the main valve body 8 through the guide 17 to move the valve seat 1.
0 to the left, and the main valve body 8 is in an open state,
The operation of the second stage is shown. The arrow ÷ indicates the flow of water;
A thick arrow + indicates the direction in which the reciprocating shaft 7 moves. The flow of water is as follows: pipe 25 + raw water side inlet/outlet 5 + inside of raw water side cylindrical body 2 ÷ gap between elastic body 13 and main valve body 8 ÷ through hole 14 , inner wall of cylindrical body 2 and outer peripheral surface of main valve body 8 The gap is divided by the right side of the main valve body 8 ÷ the raw water side bottom 6 + the pipe 26. The movement of the main valve body 8 further progresses until it reaches the position shown by the dotted line in FIG. 1, and the valve switching operation from filtration to backwashing is completed. At this time, the backwash side main valve body 8' is in close contact with the backwash side valve seat 10'. Communication for each day during backwashing is between the raw water side inlet 5 and raw water side outlet 6 in the raw water side cylindrical body 2, and the backwash side inlet 4' and backwash side inlet 5' in the backwash side cylindrical body 2'. It's mouth. The communication for each day during filtration is as follows: main valve bodies 8 and 8' are located at the positions shown by solid lines, raw water side port 4 and raw water side inlet/outlet 5 are connected to the raw water side cylindrical body 2, and backwash is connected to the raw water side cylindrical body 2'. They are a side entrance/exit 5t and a backwash side exit 6'. 14, in the drawing, a large number of holes are drilled radially around the outer periphery of the reciprocating shaft 7 and near the bearing part 15; However, in order not to increase water flow resistance, the cross-sectional area should be equal to or slightly thicker than the entrance of the through hole 14.In the drawing, the guide 1
7 guides the posture of the main valve body 8 on the outer peripheral surface of the auxiliary valve body 12, but this shape is not the only one.

In a part of the through hole 14, near where the elastic body 13 is in contact with the main valve body 8, a large opening area is provided by a method such as a bearing part 15, and a part of the outer circumferential surface of the reciprocating shaft 7 is May be guided. In this case, 17 becomes part of the valve moving tool 16.

The operation and functions of the filter of the embodiment shown in FIG. 5 will be explained in detail.

When backwashing is completed, the main valve bodies 8 and 8' in the automatic switching valve 1 are in the position shown by the dotted lines. When entering the filtration process,
Start the filtration pump 20. Raw water, which is water to be filtered, is sucked into the pump 20 and pressurized, flows through the check valve 31 and the pipe 24, and is ejected from the raw water side port 4 into the raw water side cylindrical body 2.

This jet stream pressurizes the left surfaces of the auxiliary valve body 12 and the main valve body 8 on the raw water side, pushing the main valve body 8 to the right (the main valve body 8' on the backwash side also moves to the right via the reciprocating shaft 7). The raw water side main valve body 8 is fixed on the raw water side valve seat 10 as shown by the solid line, and the auxiliary valve body 12 is in close contact with the main valve body 8 and seals the raw water sent by the pump 20. The raw water in the cylindrical body 2 exits the raw water side entrance 5, ascends the raw water/drainage pipe 25, and enters the raw water chamber 35 at the top of the filtration tank 18 through the opening 34.The raw water is pressurized by the pump 20. The water is filtered while flowing down the filtration bed 19, which is a fixed bed, and flows into the purified water pipe 27 from the lower part of the filtration tank 18 as filtered water. It enters the wash side cylindrical body 2', enters the filtered water pipe 28 from the backwash side outlet 6', rises and pushes the check valve 33 open, and enters the elevated water tank 22 for water supply from the tip of the pipe 28.
supplied within. When the filtration layer 19 becomes clogged with suspended matter, the filtration flow rate decreases, so filtration is stopped and a backwashing process begins. The method for detecting the timing of backwashing is to generate an electrical signal and send it to the control panel when a predetermined filtration resistance value is reached. Alternatively, there is a method in which a program timer is built into the control panel and commands are given once or several times every month, week, or day. Of course, the driver may manually perform the operation by looking at the pointer of the filtration pressure gauge or by looking at the filtration flow meter.

First, the filter bed pump 20 is stopped. Stand still for several to several tens of seconds until the pressure inside the filtration tank 18 reaches its lowest level. Next, the backwash pump 21 is started.

The backwash water sucked in by the pump 21 is pressurized, opens the check valve 32, ascends the pipe 29, and is ejected from the backwash water inlet 4' into the backwash side cylindrical body 2I.

This jet collides with the right surface of the main valve body 8' on the backwash side and starts moving to the left. First, the auxiliary valve body 12 opens via the reciprocating shaft 7, and then the valve moving tool 16 pushes the main valve body 8 on the raw water side, and 8 and 8
' Move to the position indicated by the dotted line, and the switch from filtration to backwashing is completed. The backwash water in the backwash side cylindrical body 2' flows from the lower part of the filtration tank 18 through the water purification pipe 27, and is filtered into the filtration tank 18.
Expand and backwash ii19. The dirty washing water that has come out of the raw water chamber 35 flows down the raw water/drainage pipe 25 from the opening 34.
The water enters the raw water side cylindrical body 2 from the raw water side outlet 5, flows down the backwash water discharge pipe 26 from the raw water side outlet 6, and is discharged into the wash drainage basin 23.

Although there is a gap between the inner wall of the cylindrical body 2 and the main valve body 8, the check valve 31 prevents backwashed wastewater from flowing back into the pump 20 through the pipe 24. The conditions under which water flow is generated by the backwash pump 21 will be explained. When the filtrate delivery pipe 12 is at a higher level than the filtration tank 18 (4) when pumping water to the elevated water tank 22, when the filtration is stopped and the water is stationary,
゛This valve body 8 has HI! The water head pressure is applied to the backwash pump 21, which is HI! A head pressure of +H1 is applied.

Therefore, the pump head for starting the pump 21 and obtaining the required amount of water flow must be higher than the piping water resistance value including Hj'+Hi and the check valves 32 and 33. Instead of sending filtered water directly to the elevated water tank 22, the filtration tank 18
When water is sent to the water storage tank #C at a lower position, the water head pressure applied to the main valve body 8 is Hl, and the water head pressure applied to the backwash pump 21 is Ht+Hi when filtration is stopped and the water is at rest.

In this case, the pump head is selected to be larger than H4+Hi10 pipe flowing water resistance value.

A usage example will be explained in detail. The pressure receiving surface of the main valve body 8 on the raw water side is A.
and its diameter was set to 10 am. The pressure receiving surface of the main valve body 8' on the backwash side was designated as A', and both diameters were designated as 10011.

The pressure receiving surface of the auxiliary valve body 12 was set to a, and its diameter was set to 5.51. The area of A is 10"X-' = 78.5 ailS
The area of a is 5.5” X f = 23.7 cd, a
+A is 23.7c+#+78.5aJζ0.30a is A
(7) It is three-tenths. The height H/ of the water head applied to the main valve body 8 is 8 m. The water pressure on side A is 0.8ky/a
lX 78.5a#=62.8&g, water pressure on 3 sides is 0.8ky/al x23.7cd=18.96&
It is g. In the conventional method without the auxiliary valve body 12,
Count 62.8ky, and if there is no pressing force exceeding this, the main valve body 8
It is not possible to open the door. In contrast, the auxiliary valve body 12 only needs to have a pressing force slightly greater than 18.96&g. The flow rate required to backwash the filtration layer 19 when selecting the backwashing pump 21 is H18m+resistance 1trL of automatic switching valve 1+piping resistance 2rrL==1177L in total in terms of a lift of 0.8-1 per minute. Therefore, the caliber is 80
We selected a submersible centrifugal pump for fresh water with an output of 2.2 kW. The performance of this pump is that when the head is 12 m, the flow rate is 0.8-1 m/min, and when the head is 14.5 yn (7), the flow rate is 0.6 m/min. The inner diameter of the through-hole 14 at the portion in contact with the elastic body 13 shown in FIG. 11ζ was 5 cm. The cross-sectional area of the through hole 14 is s"xf-=19.6cIK. Auxiliary valve body 1
The area of the pressure receiving surface S of the main valve body 8 after 2 openings is A 78.5a
f-19,6cd=58.9aj.

S+A or 58.9ail + 78.5cd=0.
75, s-plane m is 7596 of the A area. Furthermore, the through hole 14
When water starts flowing through the valve body 8, as described above, a reverse pressure is applied to the right side of the main valve body 8, and as water flows, the water pressure in that area decreases, so the pressure is relatively reduced by 30%.

The force in the closing direction applied to the main valve body 8.8 surface after the auxiliary valve body 12 opens is the force on the A surface 62.8&gX (1005%
-305%) ÷100 X75%÷100″, 33kg
It is. On the other hand, the force acting in the pushing direction obtained by starting the backwash pump 21 is 1.2&g since A' = A.
X 78.5all=94.2ky. Therefore, S
It is possible to easily open the main valve body 8, which has a large area. The filtration pump 20 was stopped from the state of the filtration process shown in FIG. 5, and after a certain timing, the backwash pump 21 was started. Immediately after startup, the auxiliary valve body 12 opens in the first stage operation, and water starts to be discharged from the backwash water discharge pipe 26.
Subsequently, the second stage operates and a large amount of water is vigorously discharged.
It became llζ. No water is discharged from the tip of the filtered water delivery pipe 28 (the main valve bodies 8 and 8' have completely moved to the position shown by the dotted line, and the switch from filtration to backwashing has been completed).

Next, the auxiliary valve body 12 was fixed to the main valve body 8 in the form of a conventional product, and the switching operation from filtration to backwashing was performed under the same conditions as the former. The filtration pump 20 was stopped from the filtration process, and the backwash pump 21 was started after a certain timing. Immediately after that, irregular internal vibrations occur inside the automatic switching valve 1, and after a few seconds, the vibrations stop, and backwash water begins to be discharged from the tip of the pipe 28 into the elevated water tank 22, and no switching operation is performed at all. There wasn't. At this time, the pointer on the pressure gauge attached to the top of the filtration tank 1 was pointing at 0.8 krt/al when it was stationary before starting the backwash pump 21, but it was 1.2 krt/al.
ky/d. The force acting in the closing direction on the main valve body 8 fixed to the auxiliary valve body 12 is 1.2&g/
There is a note that the dXA area is 78.5d-94.2&g.

This example of use shows how useful the auxiliary valve body 12 according to the invention is.

Next, the relationship and ratio between the auxiliary valve body 12, the through hole 14, and the main valve body 8 will be explained in detail. It is important to set the size of the through hole 14 to a sufficient cross-sectional area so that the resistance to water flow is as small as possible relative to the amount of water discharged. If the size of the auxiliary valve body 12 is close to that of the main valve body 8, it will be difficult to open because there is no large difference in the pressure receiving area between the two. The smaller the auxiliary valve body 12 is, the smaller the pressure-receiving area becomes, so the force required to open the valve becomes smaller. However, the population area of the through hole 14 that is closed by the auxiliary valve body 12 becomes smaller, and the water discharge flow rate per unit time becomes smaller (therefore, the pressure area around it becomes smaller. Also, the area remaining after excluding the cross-sectional area of the through hole 14 Since there is not much difference between the pressure receiving area of the main valve body 8 and the pressure receiving area of the main valve body 8 as a whole, a large force is required to move the main valve body 8 in the second stage operation, which is not suitable.

The pressure receiving area of the auxiliary valve body 12 is 2 of the pressure receiving area of the entire main valve body 8.
It is desirable that the pressure receiving area of the main valve body 8 after the auxiliary valve 4° body 12 is opened is in the range of 50 to 8096 of the pressure receiving area of the main valve body 8 as a whole.

Although the present invention describes an integrated automatic switching valve 1 in which a common sealed bearing 3 is provided in the center of the raw water side cylindrical body 2 and the backwash side cylindrical body 2', it is not limited to this. It's not something you can do.

For example, the switching valve described in Japanese Utility Model Publication No. 56-52449 can be effectively applied to an automatic switching valve provided separately for the raw water side and the backwash side as shown in the drawing.

Applications of the automatic switching valve according to the present invention include not only water, oil, and solvent filtration machines that require switching between filtration and backwashing, but also equipment that requires switching between flow in the opposite direction, such as liquid receivers. It is also usefully used as an automatic switching valve for a device for mixing two or several types of liquids contained in a tank.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view showing one embodiment of the automatic switching valve for filtration according to the present invention. 2-4 are partially enlarged sectional views of FIG. 1 showing various stages of operation of the valve. FIG. 5 is a schematic cross-sectional view of a filter incorporating the automatic switching valve of the present invention. 2.2'...... Cylindrical body 8.8'...... Main valve body ■, v'...... Valve

Claims (1)

[Claims] By changing the position of the main valve body 8, 8' that slides back and forth inside the cylindrical body 2, 2' having three openings, an inlet, an outlet, and an outlet, and stopping at a predetermined position, Two valves V and V' that enable switching between communication between the inlet and the outlet and communication between the inlet and the outlet are provided individually or integrally so that the sliding direction of the main valve body matches, the valve V;
In a switching valve in which the main valve bodies are connected by a reciprocating shaft that slidably passes through two opposing partition walls, a through hole 14 that passes through the main valve body 8 is provided inside the main valve body 8 on the raw water side. , insert the reciprocating shaft 7 into the through hole 14,
An auxiliary valve body 1 that opens and closes a through hole 14 at the raw water side end of the reciprocating shaft 7
2, and a valve moving tool 16 for transmitting the movement of the reciprocating shaft 7 toward the raw water side to the main valve body 8 at the tip end of the main valve body 8 on the raw water side.