JPS61119883A - Automatic switching valve for strainer - Google Patents

Abstract

PURPOSE:To enable shifting of a valve to filtering through easy movement of a valve body without a force being strong enough to push a main valve body on the raw water side of a pump for filtering, by a method wherein a second auxiliary valve body is movably held by means of a second valve moving tool, attached to a first auxiliary valve body. CONSTITUTION:A first valve moving tool 16A, transmitting movement of a shaft 7 to the reverse washing side to a main valve body, is located, in the rear position of a main valve body 8' on the reverse washing, to a reciprocating shaft 7. The reciprocating shaft 7 is inserted into a first through-hole 14A and a second through-hole 14B, and a second auxiliary valve body 12B, opening and closing the second through-hole 14B, is located to the end part on the reverse washing part of the reciprocating shaft 7. In order to transmit movement of the reciprocating shaft 7 to the reverse washing side to a first auxiliary valve body 12A, the second auxiliary valve body 12B is movably held by means of a second valve moving tool 16B situated to the first auxiliary valve body 12A. This constitution enables easy movement of the main valve body 8' and switching of the main valve body 8' to filtering.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an automatic switching valve for a filter. The present inventor invented it earlier in 1977.
In the automatic switching valve material filtration machine described in JP-26027, when the backwashing process is completed, high closing pressure may be applied to the filtration tank and the main valve body on the backwash side in the automatic switching valve. For example, in tall activated carbon filtration towers or rapid filtration machines, the automatic switching valve is installed at a relatively low position, and the filtrate delivery pipe opens directly into a water storage tank located below the switching valve. be. In such a case, even if the filtration pump is started after the backwash pump is stopped, the main valve body does not move and the valve cannot be switched. This is because the high water head pressure acts in the direction of closing the main valve body on the backwash side, and the discharge water flow pressure due to activation of the filtration pump is smaller than the former, and it rebounds against this pressing force and pushes back the main valve body. This is because it is not possible. In general, a filtration pump has a higher head than a backwash pump, but the flow rate is lower, so the energy to push the valve body is also smaller.

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. Two valves V and V' that enable switching between communication with the inlet/outlet and communication between the inlet/outlet and the outlet are provided individually or integrally so that the sliding direction of the main valve body matches, and the valve v, V' In a switching valve in which the main valve body is connected by a reciprocating shaft that slidably passes through two opposing partition walls, the main valve body 8 is placed inside the backwash side main valve body 8'. A first auxiliary valve body 12A is arranged, which has a first through hole 14A through which it passes, opens and closes the first through hole 14A on the backwash side of the main valve body 8', and has a second through hole 14B inside. A first valve moving tool 16A for transmitting movement of the shaft 7 toward the backwash side to the main valve body 8' is provided on the reciprocating shaft 7 at a rear position of the main valve body 8' on the backwash side, and a first through hole 14A A reciprocating shaft 7 is inserted into the second through hole 14B, and a second auxiliary valve body 12B for opening and closing the second through hole 14B is disposed at the end of the reciprocating shaft 7 on the backwashing side. In order to transmit side movement to the first sleeve auxiliary valve body 12A, a filtration mode is formed in which the second auxiliary valve body 12B is movably held by a second valve moving tool 16B provided on the first auxiliary valve body 12A. This relates to automatic switching valves.

The drawings will be explained in detail. Figure 1 is a schematic cross-sectional view of the automatic switching valve, Figures 2, 3, 4, and 5 are detailed partial cross-sectional views showing the operation of the valve, and Figure 6 is a schematic cross-sectional view of the filter. An example is shown.

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 an inlet on the raw water side, 4' is an inlet on the backwash side, 5 is an inlet on the raw water side, 5' is an inlet on the backwash side, 6 is an outlet on the raw water side, and 6' is an outlet on the backwash side. 7 is a reciprocating shaft made of metal or synthetic resin, and is preferably lightweight and has a smooth surface for sliding. 8 is the main valve body on the raw water side, and 8' is the main valve body on the backwash side.The position shown by the solid line is during backwashing, and the position shown by the dotted line is during filtration. The material of this valve body is as follows:
Made of metal, synthetic resin, or a composite thereof. The force with which this valve body operates is equal to the weight of this valve body plus the weight of the reciprocating shaft 7 multiplied by the coefficient of friction, so in order to make this valve body easy to operate, it must be lightweight. is desirable.

9 is a raw water side elastic body, 9' is a backwash side elastic body, 9 is fixed to the main valve body 8, and 9' is fixed to the main valve body 8', respectively, and they are integrated. 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 the hardness is too soft (approximately 20 degrees), valve seat 1 will be damaged when high water pressure is applied during filtration.
This is undesirable because it may sink into the 0 side and cause abnormal deformation, resulting in non-operation due to abnormal resistance during switching. Main valve body 8
and 8' are made of a soft or elastic material, the elastic material 9
．． 9' can be omitted. 10 is the raw water side valve seat, 10'
The elastic bodies 9 and 9' are in close contact with each other on the backwash side valve seat to form a water seal. Since 9.9' is an elastic body, 10.10' is preferably a rigid body. 11 is a seal ring, and a V-U ring is used for the 0-IJ song. Materials are neoprene, python,
Made of Hiker Rubber (registered trademark), etc., it is water resistant, chemical resistant,
It must be oil resistant and weather resistant, and must not lose its elasticity even at low temperatures. 12A is the first auxiliary valve body,
12B is a second auxiliary valve body made of metal, synthetic resin, or a composite thereof, and 12B is fixed to the reciprocating shaft 7. Since 12B and 12A contact 12A and 12A to form a water seal, respectively, it is preferable that one contact surface be a rigid body and the other contact surface be an elastic body. 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 when high water pressure is applied during backwashing, it may sink into the other side that is in contact and cause abnormal deformation, which may cause malfunction due to abnormal resistance during switching.

A first through hole 14A is provided in the center of the main valve body 8' and passes through the main valve body 8'. Reference numeral 14B denotes a second through hole that is provided to penetrate through the center of the first auxiliary valve body 12A. Reference numeral 15 denotes a bearing part, which is a part of the main valve body 8', and a reciprocating shaft 7 is installed in the center hole.
The valve body 8' is slidably penetrated therethrough and supports the main valve body 8' with respect to the shaft 7. A first valve moving device 16A is made of metal, synthetic resin, or a composite thereof, and is fixed to the reciprocating shaft 7 to transmit movement of the shaft 7 toward the backwash side to the main valve body 8'. 16B is a second valve moving device made of the same material as 16A, and is integrated with the first auxiliary valve body 12A, so that the movement of the shaft 7 is controlled by the second auxiliary valve body 12B.
It is transmitted to the first auxiliary valve body 12A via. 17A is the first
The guide is made of metal, synthetic resin, or a composite thereof, and is fixed to the main valve body 8' using one or several rod-shaped bodies or a hollow cylinder having many holes. Guide 17
The inside of A is slidably fitted to the outer peripheral surface of the first auxiliary valve body 12A, and when the main valve body 8' moves, it plays the role of maintaining a correct posture parallel to the reciprocating axis 7. . 17B
is a second guide and is similar to the first guide 17A. One end is fixed to the first auxiliary valve body 12A, and the second valve moving tool 16B is fixed to the other end. The inside of the guide 17B is slidably fitted to the outer circumferential surface of the second auxiliary valve body 12B, and when the first auxiliary valve body 12A moves, it maintains a correct posture parallel to the reciprocating axis 7. . The guide 17B also serves as a support for the first auxiliary valve body 12A of the second valve moving tool 16B.

FIG. 2 shows a detailed partial cross-sectional view of the backwash side cylindrical body 2' of FIG. 1, and the reference numerals are the same as in FIG. 27 is a water purification pipe,
Reference numeral 28 denotes a drainage pipe, and the details of both 27 and 28 are shown in the embodiment shown in FIG.

FIG. 3 shows the state when the second auxiliary valve body 12B 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 first auxiliary valve body 12A is opened, which is the next stage from the state shown in FIG. 3, and is the second stage of operation.

FIG. 5 shows a state in which the main valve body 8' moves further from the state shown in FIG. 4 and is the third stage of operation.

FIG. 6 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 containing silica sand, granular activated carbon,
Natural or artificial filter media such as anthracite, zeolite, various mineral particles, chamotte, synthetic resin particles, synthetic fibers, etc. are used singly or in a plurality of layers depending on various filtration purposes. 20 is a filtration bed pump, 21 is a backwash pump, which is a land-based centrifugal pump, an axial flow pump, a mixed flow pump, and
Submersible pumps are used. 23 is a cleaning drainage basin, 24
is 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. 26 is a backwash water discharge pipe, and 27 is a water purification pipe through which backwash water and filtered water flow. 28
29 is a water pipe for backwashing; 30 is an exhaust valve for exhausting the air in the filtration tank 18 and for allowing air to flow into the tank 18 as needed. 31 is a check valve that prevents the water in the pipes 24 and 25 from flowing back toward the pump 20 when the pump 20 is stopped. 32 is a check valve that prevents the water in the pipes 27 and 29 from flowing back toward the pump 21 when the pump 21 is stopped. Reference numeral 34 denotes an opening, and the raw/drainage pipe 25 opens at the upper part of the filtration tank 18, and is the outlet of the raw water during filtration, and the wastewater that has backwashed the filtration layer 19 flows into the pipe 25 during backwashing. It becomes the entrance. The distance between the upper surface of the opening 34 and the upper surface of the filtration layer 19 is called the sand depth, and when the filter medium is filter sand, the standard value is 50 to 60 ai. 35 is a raw water chamber. 36 has an inverted U shape at the top of the water purification pipe. A 37 siphon cut valve is provided at the top. This valve is the filtration layer pump 20, the backwash pump 2
This is to inhale air and turn off the siphon when 1 is stopped. The height of the water purification pipe upper part 36 is approximately the same height as the opening 34. The reason for this is that when the filtration bed pump 20 stops and then starts up, if there is not enough water in the raw water chamber 35, the water jetting out from the opening 34 will disturb the upper surface of the fixed bed of the filtration bed 19, causing the filtrate This is because it impairs accuracy. Ht is the static water head applied to the main valve body 8' on the backwash side, and the water surface represents the state when the backwash process is performed at the top of the opening 34 and the pump 21 is stopped.

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 6, the positions of the main valve bodies 8 and 8' shown by solid lines represent the states during backwashing and immediately after stopping backwashing, and the positions shown by dotted lines represent the states during filtration and after filtration. This shows the state immediately after stopping. The conditions under which the main valve bodies 8 and 8' can be moved from the backwash position shown by the solid line to the filtration position shown by the dotted line by starting the filter bed pump 20 will be described. In FIG. 6, the state of the water when the backwashing process is completed, the backwash pump 21 is stopped, and the backwash wastewater is discharged from the pipe 26 is as follows: 2
Inside, the backwash water discharge pipe 26 is empty of water. In addition, the main valve body 8 is inside the filtered water delivery pipe 28 and inside the backwash side cylindrical body 2'.
The water to the left of ′ is empty. On the other hand, on the right side of the main valve body 8' on the backwash side, the water is full and the hydrostatic pressure of Ht is applied to the main valve body 8'.
rests on the surface of The main valve body 8' receives water pressure of Ht.
If the pressure receiving surface of is A'd, the force acting in the closing direction is HtxA'. The pressure receiving surface of the main valve body 8 on the raw water side that receives the water flow from the filtration bed pump 20 is ACFI! shall be. 6th
In the case of the pressurized filter shown in the figure, A''' and A are.If the discharge pressure of the pump 20 is Hp, the force required to move the valve bodies 8 and 8' is Hp-A>Ht-A. '10 reciprocating axis 7
is the sliding resistance.

The greater Ht, the greater the discharge pressure required. If A' becomes smaller than A, Hp can also be smaller. However, making A' extremely smaller than A increases the backwash water resistance, causes a decrease in the backwash flow rate per unit time, and impairs the recovery performance of the filtration layer 19 due to backwashing, so this must be avoided. Next, the discharge pressure and flow rate of the filtration bed pump will be described.The maximum filtration resistance in general rapid filtration is within 10 Ω, and including the piping resistance, it is 207 r.
＋、Choose one or more. The flow rate is small compared to the backwash pump 21. When the filtration rate is 6 m/hour and the backwash rate is 36 m/hour, the flow rate of the filtration application pump 20 is 6 m = 36 rrL = 'A of the flow rate of the backwash pump 21. The pump 20 has a high head but a small flow rate. Between the outer peripheral surface of the raw water side main valve body 8 and the inner wall surface of the raw water side cylindrical body 2,
A gap between the two circles is provided. This gap is the main valve body 8 on the raw water side.
When moving to the left from the position shown by the dotted line to the position shown by the solid line, the water in the raw water side cylindrical body 2 is not compressed and flows through the gap to the right of the main valve body 8 (main valve body It plays the role of smoothing the switching by escaping in the direction opposite to the direction of movement. The backwash side cylindrical body 2' also has a similar function. Since the flow rate of the filtration application pump 20 is small, if the gap area is too wide for the flow rate, a large amount of water will pass through the gap.
As a result of the water escaping, the discharge pressure Hp of the pump 20 no longer acts on the left side of the main valve body 8 shown by the solid line within the raw water side cylindrical body 2, and the force pushing the main valve body 8 to the right is weak. Become.

The present invention does not require that the size of the main valve body 8' on the backwash side be smaller than that of the main valve body 8 on the raw water side (as shown in FIGS. 1 to 5).
A first auxiliary valve body 12A and a second auxiliary valve body 12B are provided in the central portion of the main valve body 8'. Since the pressure receiving area of the auxiliary valve body 12A112B is small as shown in the drawing, the force required to open it is small, and it can be opened easily by the pushing force of the main valve body 8 on the raw water side. When the valve body 12B opens, water starts to be discharged through the second through hole 14B and the first through hole 14A as shown in FIG. 3. In FIG. The water in the pipe flows out to the filtered water delivery pipe 28 through 14B and 14A, and the water level in the pipe drops.Also, when flowing water occurs, the second
Water pressure in the opposite direction to that when closing will be applied to the back surface of the auxiliary valve body 12B and the back surface of the first auxiliary valve body 12A, that is, the left side, so push the first auxiliary valve body 12A in the closing direction, that is, to the left. The power decreases. Furthermore, since the pressure receiving area of 12A is small, the pushing force of the main valve body 8 on the raw water side easily pushes the first auxiliary valve body 1.
2A can be opened.As shown in Fig. 4, the auxiliary valve body 1
When 12A opens following 2B, the flow rate of water discharged through the first through hole 14A increases. In Figure 6, water purification pipe 2
The water in the left pipe of No. 7 flows out through the through holes 14B and 14A to the filtrate delivery pipe 28, and the water in the pipe flows out completely and becomes empty, or drops to a position where it is in equilibrium with the water head in the pipe 28. . In such a situation, the main valve body 8' on the backwash side shown by the solid line
The pressures on the right and left sides are completely balanced, and the force that was pushing the backwash side main valve body 8' in the closing direction, that is, to the left, is now zero. Therefore, even if the force pushing the raw water side main valve body 8 of the filtration application pump 20 is not so strong, it is possible to easily move the main valve body 8' to the right and switch the valve to filtration.

Next, the main valve body 8' and its operations and functions will be explained in detail using FIGS. 1 to 5. FIG. 1 shows a backwashing state in which the main valve body 8' is closed. The backwash side elastic body 9' is in close contact with the backwash side valve seat 10', and the first auxiliary valve body 12
A is in close contact with the main valve body 8', and the second auxiliary valve body 12B is in close contact with the first auxiliary valve body 12A.
4B is sealed with water. When backwashing is being performed, backwash water enters the backwash side cylindrical body 2' through the backwash side inlet 4', exits through the backwash side inlet/outlet 5', and is sent to the filter. Backwash wastewater that has been backwashed within the filter enters the raw water side cylindrical body 2 from the filter through the raw water side inlet/outlet 5, and is discharged to the outside of the system from the raw water side outlet 6. Figure 2 shows the main valve body 8' in the state shown in Figure 1.
The part is enlarged. When switching from backwashing to filtration, first stop the supply of backwash water from the backwash side inlet 4' shown in Figure 1, lower the water pressure applied to the main valve body 8' on the backwash side to the lowest level, and then Raw water is sent from side population 4. This water flow acts on the pressure receiving surface on the left side of the main valve body 8 on the raw water side and pushes the main valve body 8 to the right, and the reciprocating shaft 7 moves to the right and the second auxiliary valve body 12B
Open. FIG. 3 shows the operation of this first stage of switching. The right side of the second auxiliary valve body 12B comes into contact with the left side of the second valve moving tool 16B fixed to the first auxiliary valve body 12A via the second guide 17B, and the valve body 12B stops opening.

The distance between the left side of the second auxiliary valve body 12B and the right side of the first auxiliary valve body 12A, which was water-sealed by the valve body, is approximately 2 cm when the outer diameter of the valve body 12B is 41 cm, and is approximately 2 cm when the outer diameter is 71 cm. In this case, about 3 cm is appropriate. The flow of water when the second auxiliary valve body 12B opens is indicated by an arrow ←. That is, the water in the pipe 27 is divided into →backwash side inlet/outlet 5'→inside the backwash side casing 2'→gap between second auxiliary valve body 12B and first auxiliary valve body 12A÷second through hole 14B+first through hole Hole 14A → left side of main valve body 8′ ÷ backwash side hole 6′ → pipe 28.

FIG. 4 shows that the second auxiliary valve body 12B pushes the second valve moving tool 16B, pulls the first auxiliary valve body 12A through the second guide 17B, and separates it from the main valve body 8' to the right, causing the valve to move. The second stage operation is shown with the body 12A open. The right side of the first valve moving tool 16A fixed to the reciprocating shaft 7 comes into contact with the left side of the bearing portion 15 of the main valve body 8', and the opening of the valve body 12A is stopped. 1st
The appropriate distance between the left side of the auxiliary valve body 12A and the right side of the water-sealed main valve body 8' is about 3 to 4 cm when the outer diameter of the valve body 12A is 100I. Auxiliary valve body 12B, 12A
The arrow ← indicates the flow of water when it opens. Arrow→
represents the direction in which the reciprocating shaft 7 moves.

Water flow is from pipe 27 + backwash side inlet/outlet 5' → backwash side cylindrical body 2
' Inside → From the gap between the second auxiliary valve body 12B and the first auxiliary valve body 12A, the second through hole 14B, the first auxiliary valve body 12A and the main valve body 8
′ ÷ first through hole 14 A + left side of main valve body 8 ′ → backwash creation hole 6 ′ → pipe 28.

FIG. 5 shows the third stage operation in which the first valve moving tool 16A pushes the main valve body 8' and pulls it away from the valve seat 10' to the right, opening the main valve body 8'. The arrow ← indicates the flow of water, and the arrow →
indicates the direction in which the reciprocating shaft 7 moves. From the gap with the auxiliary valve body 12A to the second through hole 14B, the gap between the first auxiliary valve body 12A and the main valve body 8' → the first through hole 14A, the inner wall of the cylindrical body 2' and the main valve body 8'
Gap with the outer peripheral surface → left side of main valve body 8' → backwash creation hole 6'
→It becomes tube 28. The movement of the main valve body 8' further progresses, and the first
As shown by the dotted line in the figure (the main valve body 8 on the raw water side is connected to the valve seat 10 on the raw water side).
The valve switching movement from backwashing to filtration is completed when the valve is in close contact with the valve.

During filtration, the main valve bodies 8 and 8' are indicated by dotted lines in FIG. Inside, there is a backwash side inlet/outlet 5' and a backwash side outlet 6'. The communication for each day during backwashing is as follows: the main valve bodies 8 and 8' are located at the positions shown by solid lines, and the raw water side inlet/outlet 5 and the raw water side outlet 6 in the raw water side cylindrical body 2.
, a backwash side inlet 4' and a backwash side inlet/outlet 5' in the backwash side cylindrical body 2'. 14A, in the drawing, a number of holes are drilled radially to the outer peripheral surface of the reciprocating shaft 7 in the vicinity of the bearing part 15, but the shape is not limited to this. It may also be provided through. However, in order not to increase water flow resistance, the cross-sectional area of the inlet of the first through hole 14A should be equal to or slightly larger. Also, in the drawings, the first guide 17A maintains the posture of the main valve body 8' on the outer peripheral surface of the first auxiliary valve body 12A, and the second guide 17B maintains the posture of the main valve body 8' on the outer peripheral surface of the second auxiliary valve body 12B. Although each person has their own version of the t2A posture, they cannot be confined to just this form. Through hole 1
4A and 14B, a through hole is provided in the vicinity of the inlet where the auxiliary valve bodies 12A and 12B come into contact, using a method similar to the bearing part 15 to have a sufficiently wide opening area, and a part of the outer circumferential surface of the reciprocating shaft 7 is used as an auxiliary valve. One valve body 8' may be held for the valve bodies 12A and 12B. In this case, the illustrated guide 17B becomes a part of the valve moving tool 16B.

The operation and functions of the filter according to the embodiment shown in FIG. 6 will be explained in detail. During and after the filtration process,
The main valve bodies 8 and 8' in the automatic switching valve 1 are in the positions indicated by the dotted lines.

When entering the backwashing process, the filtration application pump 20 is stopped, and then the backwashing pump 21 is started. Backwash water is pump 21
The water is pumped up and pressurized to push open the check valve 32, flow through the backwash water pipe 29, and jet out from the backwash side inlet 4' into the backwash side cylindrical body 2'. This jet flow is caused by the auxiliary valve body 12B,
12A and the right surface of the main valve body 8' on the backwash side, and push the main valve body 8' to the left. The main valve body 8 on the raw water side also has a reciprocating shaft 7
Move left through. The backwash side main valve body 8' is fixed to the backwash side valve seat 10', and the auxiliary valve body 12B is fixed to 12A, 12A
are in close contact with the main valve body 8', and seal the backwash water sent by the pump 21 to the filtrate delivery pipe 28, respectively. The backwash water in the backwash side cylindrical body 2' is connected to the backwash side inlet/outlet 5'.
The water exits the water purification pipe 27, goes up the water purification pipe 27, makes a U-turn at the upper part 36 of the water purification pipe, goes downward on the right side of the water pipe 27, and flows into the tank from the lower part of the filtration tank 18. The inflowing backwash water expands the filter layer 19 and backwashes the blocked suspended matter. Raw water room 3
The dirty backwash water discharged in step 5 is drained from the opening 34 to the source/drain pipe 2.
5, enters the raw water art body 2 from the raw water side entrance 5, flows down the backwash water discharge pipe 26 from the raw water side outlet 6, and is discharged to the washing drainage basin 23. Although there is a gap between the inner wall of the cylindrical body 2 and the outer peripheral surface of the main valve body 8, the check valve 31
Therefore, the backwashed waste water will not flow back to the pump 20 through the pipe 24. Backwash time is usually about 6 to 8 minutes. When the backwashing is completed, the backwashing pump 21 is stopped. The main valve bodies 8 and 8' remain in the position shown by the solid line. Since the mouth at the tip of the pipe 26 is open to the atmosphere at the drainage basin 23, the water in the raw water chamber 35 flows through the pipe 25 + inlet/outlet 5 → tubular body 2 → outlet 6 → pipe up to the upper surface position of the opening. 26 and is discharged to the outside, and as time passes, the water disappears and becomes a space. At this time, air enters the raw water chamber 35 from the exhaust valve 30. The inside of the water purification pipe 27 is full of water, and the water pressure of Ht is acting on the right side of the main valve body 8' on the backwash side in the closing direction.

Under such conditions, the filtration application pump 20 is started.

Raw water, which is the water to be filtered, is pumped up by the pump 20, pressurized, pushes open the check valve 31, flows through the raw water 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 surface of the main valve body 8 on the raw water side, and the main valve body 8 receives this force and starts moving to the right. First, the second auxiliary valve body 12B opens via the reciprocating shaft 7 (as shown in FIG. 3), and then the first auxiliary valve body 12A opens (as shown in FIG. 4). Subsequently, the main valve body 8' is pushed to the right (as shown in FIG. 5) and begins to move. Both the valve bodies 8 and 8' move to the positions indicated by dotted lines in FIGS. 1 and 6, and the switch from backwashing to filtration is completed. The main valve body 8 on the raw water side is fixed on the raw water side valve seat 10 and directs the raw water sent by the pump 20 into the pipe 26 as shown by the dotted line.
Water seal against. 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 above the filtration tank 18 through the opening 34. Raw water, which is water to be filtered and which is pressurized by the pump 20, is filtered while flowing down the filtration layer 19, which is a fixed bed, and flows into the water purification pipe 27 from the lower part of the filtration tank 18 as filtered water. The filtered water that has ascended through the pipe 27 reaches the purified water pipe upper part 36, makes a U-turn, descends the left pipe 27, enters the backwash side cylindrical body 2' through the backwash side entrance 5', and enters the backwash side outlet 6'. The filtered water flows through the filtered water delivery pipe 28 and is supplied to a filtered water tank or a water distribution reservoir. When the filtration layer 19 becomes clogged with suspended matter, the amount of filtration water decreases, so filtration is stopped and a backwashing process begins. As a method for detecting the timing to perform backwashing, when a predetermined filtration resistance value or filtration flow rate value is reached, an electric signal is generated and sent to the control panel.

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 perform manual operation by looking at the pointer of the pressure gauge or the flow meter of the filtrate. First, filtration pump 2
Stop 0. Stand still for several to several tens of seconds until the pressure inside the filtration tank 18 reaches its lowest level. After that, the backwash pump 21
When you start it, it will start the backwashing process as described above.

In the drawing, two auxiliary valve bodies 12A and 1 are attached to the main valve body 8' on the backwash side.
2B, but if a high hydrostatic head is applied to the main valve body 8' when backwashing is stopped, or if the outer diameter of the main valve body 8' is as large as 30-40cm or 50Q11, If three or several auxiliary valve bodies are provided and the auxiliary valve body with the smallest diameter is sequentially opened to the main valve body, valve switching can be performed effectively.

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', the present invention is limited to this. It is not something that will be done. The switching valve described in Japanese Utility Model Publication No. 56-52449 can also be effectively applied to an automatic switching valve provided separately for the raw water side cylindrical body and the backwash side cylindrical body as shown in the drawing.

Applications of the automatic switching valve according to the present invention include not only filters for water, oil, solvents, etc. that require switching between filtration and backwashing, but also equipment d that requires switching between flow in the opposite direction, such as a receiving valve. It can also be effectively used as an automatic switching valve for a device for mixing two or several types of liquids contained in a liquid tank.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of an automatic switching valve for a filter according to the present invention. 2-5 are partial cross-sectional views showing various stages of operation of the switching valve of FIG. 1; FIG. FIG. 6 is a schematic diagram of a filter incorporating the switching valve of FIG. 1. 2.2'...Cylindrical body 8.8'...Main valve body, 7...Reciprocating shaft ■, 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, In the switching valve in which the main valve bodies are connected by a reciprocating shaft that slidably passes through the two opposing partition walls of the valves V and V', a main valve body 8 is provided inside the backwash side main valve body 8'. ′
A first auxiliary valve body 12A is arranged, which opens and closes the first through hole 14A on the backwash side of the main valve body 8' and has a second through hole 14B inside. A first valve moving tool 16A is provided on the reciprocating shaft 7 at a rear position of the main valve body 8' on the backwash side to transmit the movement of the shaft 7 toward the backwash side to the main valve body 8'. 14A and second through hole 14
A reciprocating shaft 7 is inserted into B, and a second auxiliary valve body 12B that opens and closes the second through hole 14B is arranged at the end of the reciprocating shaft 7 on the backwashing side to prevent movement of the reciprocating shaft 7 toward the backwashing side. An automatic switching valve for a filter, in which the second auxiliary valve body 12B is movably held by a second valve moving tool 16B provided on the first auxiliary valve body 12A in order to transmit information to the first auxiliary valve body 12A.