JP2525929B2 - Two-way switching valve for intermittent vacuum filtration device - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a two-way switching valve for an intermittent vacuum filtration device, and more specifically, a two-way switching valve used together with an intermittent vacuum filtration device so that the vacuum filtration section of the filtration device is alternately connected to a vacuum source and the atmosphere. Regarding the valve.

[Prior art]

The intermittent vacuum filtration device is an endless filtration belt forming a substantially horizontal upper traveling portion, as described in a prior British patent application by the inventor of the present invention, for example, British Patent Application No. 8820005.0. Alternatively, a filter cloth is provided, and a filtration treatment material such as slurry to be filtered is supplied to the upper running portion of the endless filtration belt. The filtration belt or filter cloth is driven to advance intermittently, and when the upper traveling portion continuously travels above the vacuum boxes or vacuum tray rows over their entire length, each vacuum box or vacuum tray is moved from the slurry. Liquid is drawn from the slurry through the filter belt or filter cloth, which results in the separation of solids in the slurry that remain on the filter belt or filter cloth to form a filter cake. The inventors of the present invention alternately switch the connection between the vacuum source (when the belt is stopped) and the atmosphere (when the belt is operating) in the vacuum filtration unit (vacuum box or vacuum tray) of the intermittent vacuum filtration device. A so-called two-way switching valve has been proposed. The two-way switching valve has a main body pipe part having side openings communicating with the vacuum filtration part of the intermittent vacuum device and having both end openings communicating with the atmosphere and a vacuum source, and both end openings of the main body pipe part. More annular and annular step portions respectively arranged on both side portions of the side opening portion, a piston member reciprocally provided inside the main body pipe portion, and attached to one end portion of the piston member, In accordance with the reciprocating movement of the piston member, the piston moves inside the main body tube portion and comes into airtight contact with one of the two annular step portions, whereby the side opening portion and the other main body tube portion on the annular step portion side It is composed of a sealing disk member that can be electrically connected to the end opening. The side opening communicates with the opposite end openings of the main body tube portion that are connected to the vacuum source and the atmosphere so that a gap exists between the inner peripheral surface of the main body tube portion and the outer peripheral surface of the sealing disk member. To be done. In the intermittent vacuum filtration device, in order to efficiently perform the filtration process, connection switching between the vacuum filtration unit and the vacuum source or the atmosphere can be operated at a high repetition frequency (for example, 6 cycles per minute), and the filtration non-operation can be performed. Minimal operating periods are required.

[Problems to be Solved by the Invention]

The drawback of using a two-way switching valve of the type described above is that the airtightness is low, so that even if the vacuum port is closed by the sealing disk member, the flow of the filtrate does not completely stop,
Also, it does not stop at the moment it is closed. In other words, the flow of filtrate continues for some time after the vacuum source is closed. Depending on the two-way switching valve having the above-described structure, there is a risk that the filtrate may be accumulated on the sealing disk member and overflow from the ventilation hole provided at the one end opening of the main body tube portion. When the atmospheric pressure of the vacuum port and the atmospheric port are at the same level, or when the atmospheric pressure of the vacuum port is higher than the atmospheric pressure of the atmospheric port (this condition is not desirable), the filtrate always leaks when the vacuum source is closed. It is clear to do. If the sealing disk member subsequently moves to the other position and closes the vent hole, the filtrate may accumulate behind the disk member, or the extremely corrosive harmful filtrate may flow upward or sideways. There is a risk of scattering and part of it flowing out of the ventilation holes. It is an object of the present invention to solve the above-mentioned serious problems, and to solve the above-mentioned drawbacks, it is possible to provide a device for an intermittent vacuum filtration device.
It is to provide a one-way switching valve.

[Means for Solving the Problems]

According to the present invention, in order to solve the above-mentioned problems, according to the present invention, an annular step portion of the opening at both ends of the main body tube portion, which is in communication with the vacuum source, and / or a sealing disk in airtight contact with the annular step portion. A contact passage is provided on the contact surface of the member, and when the sealing disk member is in airtight contact with the annular step on the vacuum source side, the side opening, the contact passage, and the main body from the vacuum filtration portion of the intermittent vacuum filtration device. The filtrate can be circulated to the above vacuum source through the end opening of the pipe, and thus the filtrate that continues to flow even after the vacuum source is closed can be effectively sucked and discharged with a small suction amount. It In this way, reliable and safe operation can be ensured. The shape of the elongated holes or grooves forming the above-mentioned conduction path and the set number thereof can be designed according to the purpose of use. In the case of a material having good filterability, a relatively large elongated hole or groove is required because a large amount of the filtrate continues to flow due to gravity and a large amount of the filtrate remains in the pipe. Conversely, at the downstream end of the filter (which has less filtrate since it is mostly removed on the upstream side), smaller slots or grooves are suitable. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings showing embodiments.

【Example】

In FIG. 1, the valve main body of the two-way switching valve of the present invention is constructed by using a T-shaped pipe member 10 having a side opening, and a cylinder is provided at each end of the main body pipe of the T-shaped pipe member 10. Insert members 11 and 12 are attached, and annular step portions 13 and 14 facing each other are formed on both sides of a lateral arm portion 15 formed at an intermediate portion of the main body tube portion. Then, shallow outward facing step portions 16 and 17 are formed on the inner peripheral surface of the T-shaped tube member 10 at positions spaced from both end portions by a certain distance, and the cylindrical insertion member 11 and the cylindrical insert member 11 are formed on these step portions 16 and 17, respectively. One end of 12 is locked and positioned, and the cylindrical insertion members 11 and 12 are welded or screwed to this position. The annular step portions 13 and 14 formed in this manner are T
It is substantially perpendicular to the longitudinal axis of the V-shaped tube member 10. Sealing members 21, 21 'such as rubber on both sides of the disk 20
And the disc 20 is connected to a piston rod 22 extending in the longitudinal direction of the T-shaped tubular member 10. As shown in the upper part of FIG. 1, the piston rod 22 extends from a pneumatic cylinder 23 mounted on top of the cylindrical insert 11. The diameter of the disk 20 is made smaller than the inner diameter of the main body tube portion of the T-shaped tube member 10, and the inner peripheral surface of the main body tube portion and the disk 20 are
A gap is formed between the outer peripheral surfaces of the. The diameter of the disk 20 is such that the peripheral edge portion can surely contact the annular step portions 13 and 14. Sealing members 21 and 21 'made of, for example, a rubber material are attached to both surfaces of the disk 20, respectively. Among these sealing members, a sealing member 21 'that can come into contact with the annular step portion 14 is provided with a radial groove 28 or an elongated hole 29 having a shape as shown in FIGS. 1a and 1b. One cylindrical insertion member 11 is formed by using a perforated tube or spool and is provided with a large number of through holes 18. The valve device of the above embodiment is held between the plates 24, 25 by four tie rods 26 (only one is shown in FIG. 1). Practically, the lateral arm portion 15 of the T-shaped tube member 10 is welded or flange-attached to a pipe 27 as shown in FIG. 1, and the pipe 27 has an intermittent vacuum filtration device (third embodiment) which will be described later.
(Fig. 4, Fig. 4) in communication with a vacuum tray arranged under the filter or filter belt. The other cylindrical insert 12 is in communication with a vacuum source. Cylindrical insert
Each hole 18 of 11 is directly connected to the atmosphere. Pneumatic cylinder
23 drives the disk 20 to move forward or backward via the piston rod 22, so that the sealing members 21 ', 21 on both sides of the disk 20 alternate with the lower annular step 14 and the upper annular step 13, respectively. To be in airtight contact with. When the disk 20 is pulled up by the pneumatic cylinder 23 through the piston rod 22 and comes into contact with the upper annular step portion 13, the lateral arm portion 15 of the T-shaped tube member 10 is inserted into the cylindrical insertion member.
Conduct with 12. In this way, the pipe 27 connected to the lateral arm portion 15, and therefore the vacuum tray of the intermittent vacuum filtration device, which is in communication with the pipe 27, is electrically connected to the cylindrical insertion member 12, and the filtrate from the filtration device is discharged. Are sucked toward the vacuum source via the two-way switching valve. On the other hand, as the disk 20 is pushed down by the pneumatic cylinder 23 via the piston rod 22, the vacuum pressure decreases, and the filtrate discharge line to the vacuum source is released. However, in this case, even if the disk 20, and thus the sealing member 21 ', comes into contact with the lower annular step 14, the radial groove 28 or the slot 29 provided in the sealing member 21' completely closes the vacuum pressure. Not, the filtrate sucked from the filter material present in the filter part of the above-mentioned filtration device or the upper part of the vacuum tray is a vacuum source connected to the lower cylindrical insert member 12 through the radial groove 28 or the elongated hole 29. Continue to be sucked towards. When the disk 20 reciprocates in the T-shaped tube member 10 as described above, when the disk 20 is brought into pressure contact with the upper annular stepped portion 13, a strong vacuum is generated in the lower cylindrical insert member 12, while the lower side is A vacuum is generated in the lower cylindrical insertion member 12 through the radial grooves 28 or the elongated holes 29 of the sealing member 21 ′ which is brought into pressure contact with the annular step portion 14, although it is weak, and in this manner, the vacuum is generated in accordance with the reciprocating motion of the disk 20. The vacuum force acting on the arm portion 15 changes alternately. The speed at which the disk 20 moves between the two annular steps 13 and 14 is actually very high, and the time required for one-way movement is on the order of a fraction of a second. Usually, the switching of the movement of the disk 20 is performed at intervals of 10 seconds, for example. Precipitation of filtrate on the disk 20, overflow from each through hole 18 of the cylindrical insertion member 11, especially piston rod
The problem of splashing the accumulated filtrate through each hole 18 during the upward stroke of 22 is effectively solved by the radial groove 28 or the long hole 29 formed in the sealing member 21 'attached to the disk 20. be able to. FIG. 2 shows a further improved embodiment of the two-way switching valve of the present invention. Also in this embodiment, the cylindrical insertion members 111 and 112 are used.
Are respectively fitted to opposite end portions of the main body pipe portion of the T-shaped pipe member 110, and annular step portions 113, 11 facing each other are provided on both side portions of the lateral arm portion 115 in the main body pipe portion of the T-shaped pipe member 110.
4 is formed. In this embodiment, the T-shaped tube member 1
The formation of the step portion for defining the fixing position of the cylindrical insertion members 111, 112 on the inner peripheral surface of 10 is omitted. Instead, the outer peripheral surface of one end of the upper cylindrical insert member 111 formed by using a spool member having a large number of through holes 118 is welded to the quadrangular flange 124. The square flange 124
Is fixed to the top of the T-shaped tubular member 110 via a gasket 128. On the other hand, the lower cylindrical insert member 112 is similarly connected to the quadrangular flange 125 and also connected to the lower end portion of the T-shaped pipe member 110 via the gasket 129. Regarding this embodiment, the most important difference from the first embodiment shown in FIG. 1 is that, as is apparent from FIG. 2a, grooves 130 are radially provided in the upper edge portion of the lower cylindrical insertion member 112. That is. Inside the T-shaped tube member 110, a steel disk 120 whose both surfaces are covered with a rubber sealing member 121 is screwed and fixed to a piston 122 of a pneumatic cylinder 123 above the spool 111. In this case, neither of the rubber sealing members 121 is provided with a groove or an elongated hole. Practically, similar to the embodiment of FIG.
The lateral arm portion 115 is connected to the vacuum tray to form a part of the filtering means, and the cylindrical insertion member 112 is connected to the vacuum source. The cylinder 123 reciprocates the disk 120 to make air-tight contact with the annular stepped portion 113 or 114, thereby alternately connecting the filtrate line with the vacuum source and the atmosphere. Operation and advantages are similar to the embodiment of FIG. 1, but
In this embodiment, when the disk 120 is connected to the step portion 114 at the lower end position, the residual filtrate is discharged through the groove 130 of the cylindrical insertion member 112. When the groove or slot is provided in the sealing disk member (20, 21 ') itself as shown in FIG. 1, or as shown in FIG. 2, an annular ring adjacent to the vacuum port of the two-way switching valve. Whether it is in contact with the step or not, it is possible to make various changes in its structure, particularly in the shape, size and position of the groove. In order to fully understand the true value and purpose of the two-way switching valve shown in FIG. 1 and FIG. 2 described above, there are two types of modifications of the vacuum filtration device that enable effective use of the device. It is shown in FIG. In the first intermittent vacuum filtration system shown in FIG. 3, an infinite filter belt 30 is passed around rollers 31-37,
The rollers are supported by the frame 40 and the upper running portion is substantially horizontal.
30 and the downward return traveling part are formed. In the upper traveling portion 38, the reciprocating motion of the cylinder 42 causes the downstream roller 31 to intermittently move forward in the direction indicated by the arrow. When the roller 31 is pushed forward to the position shown by the broken line, the upper traveling portion moves forward by a certain distance. The backward movement of the downward return traveling unit is prevented by a one-way device incorporated in the pair of rollers 33, 34, for example, a one-way drive device or a pawl ratchet device. As the roller 31 advances, the tensioning roller 36 moves to the right along the guide slot. When the roller 31 is pulled back again, the tensioning roller 36 moves to the left under the influence of the weight 44, and the looseness of the belt is eliminated. Every time the upper arm 38 makes one step, the slurry to be filtered is supplied to the upstream side of the arm via the supplying means 46.
While the upper arm 38 is advancing intermittently, the belt 30 and the slurry deposited on it are washed by the spray 47 and moved on the continuous sections of the vacuum tray 48. Each compartment is joined by a respective pipe 50 to a manifold 52, which is in communication with a vacuum source, such as a vacuum pump 54. The two-way switching valve of FIG. 1 or 2 is installed in a pipeline, generally indicated at 60, from the manifold 52 to the pump 54. While the belt 30 is stopped, the vacuum tray 48 and the slurry are vacuumed. Each time the belt 80 is intermittently advanced, the disk 20 or 12
The vacuum is stopped by moving 0 from step 13 or 113 to step 14 or 114. Then, the communication pipeline is released to the atmosphere, and this state is maintained for a while. When the roller 31 reaches the foremost position and the belt 30 stops again, the disk 20 moves backwards in the device 60 to join the step 13 or 113 and the vacuum is reapplied. By the end of the upper traveling section, the slurry is completely dehydrated and a solid filter cake remains on the belt 30,
This remaining filter cake is removed by doctor blade 56 before cleaning at 58. The example of the second intermittent vacuum filtration device shown in FIG. 4 is further schematicized. Since this operates in the same manner as the example of FIG. 3, detailed description will be omitted. Among the constituent parts in the figure, those equivalent to the constituent parts in the apparatus of FIG. 3 are indicated by adding a dash (') to the same numeral reference.

[Brief description of drawings]

FIG. 1 is a side sectional view of a first embodiment of a two-way switching valve according to the present invention applied to a vacuum filtration device, FIG. 1a is an enlarged bottom view of a sealing disc member, and FIG. 1b is another sealing disc member. FIG. 2 is an enlarged bottom view of FIG. 2, FIG. 2 is a side sectional view of a second embodiment of the two-way switching valve of the present invention, FIG. 2a is a sectional view taken along the line II-II of FIG. 2, and FIG. FIG. 2 is a side view of an example of an intermittent vacuum filtration device incorporating the two-way switching valve shown in FIG. 2, and FIG. 4 is a side view of another example of the intermittent vacuum filtration device incorporating the two-way switching valve of the present invention. 10 ... T-shaped tube member 11 ... Cylindrical insertion member 12 ... Cylindrical insertion member 13 ... Annular step portion 14 ... Annular step portion 16 ... Step portion 17 ... Step portion 18 ... Hole 22 ... Disk 21, 21 ', 121 ... Sealing Member 22 ... Piston rod 23 ... Pneumatic cylinder 28 ... Radial groove 29 ... Slot

Claims (6)

(57) [Claims] 1. A two-way switching valve which is used together with an intermittent vacuum filtration device to switch the vacuum filtration part of the filtration device so as to alternately connect to a vacuum source and the atmosphere, and which is in communication with the vacuum filtration part. A main body tube portion (10; 110) having side opening portions (15; 115) that are opened and both end opening portions that communicate with the atmosphere and a vacuum source; Annular steps (13, 14; 113, 114) respectively arranged on both sides of the side opening, a piston member (22; 122) reciprocally movable inside the main body tube, and the piston It is attached to one end of the member and moves inside the main body tube portion in response to the reciprocating movement of the piston member to make air-tight contact with one of the annular step portions, whereby the side opening and the other annular portion. Sealing disk that allows continuity with the end opening of the main body tube on the step side (20,21,21 '; 120,
121, 121) for a two-way switching valve for an intermittent vacuum filtration device, wherein an annular step portion (14; 114) on the side communicating with the vacuum source in the opening portions at both ends of the main body pipe portion and / or The annular step (14; 1
14) said sealing disc member (20; 1) in airtight contact with
The contact surface portion (21 '; 121) of 20) is provided with a conduction path (28,29), and when the sealing disk member is in airtight contact with the annular step portion (14; 114) on the vacuum source side, the intermittent vacuum filtration device. From the vacuum filtration section of the side opening (15; 115), the flow path and the end opening of the main body tube portion to the vacuum source, enabling the flow of filtrate. Two-way switching valve for intermittent vacuum filtration equipment. 2. A cylindrical insertion member (11, 1) in which an annular step portion (13, 14; 113; 114) is attached to an end opening portion of a main body pipe portion (10; 110).
2; 111,112), 2 as defined in claim 1.
One-way switching valve. 3. A first step in which an annular step portion (13, 14; 113; 114) is formed so as to project perpendicularly to the inner peripheral surface of the main body pipe portion (10; 110).
The two-way switching valve according to item or item 2. 4. The two-way switching valve according to any one of claims 1 to 3, wherein the main body pipe portion (10; 110) is a T-shaped pipe member. 5. The first to fourth aspects, wherein a perforated tubular member is attached to one end opening of the main body tube portion (10; 110) to communicate with the atmosphere.
A two-way switching valve according to any one of items. 6. A sealing material layer is used to connect the other end of the piston member (22; 122) to the output shaft of the pneumatic cylinder device (23; 123) and the sealing surface of the sealing disk member connected to one end of the piston member. Formed, first
The two-way switching valve according to any one of items 5 to 5.