Valve unit and pinch valve body

Abstract

To provide a valve unit and a pinch valve body that enable smooth conveyance of a conveying object while ensuring low cost and excellent energy saving.SOLUTION: A valve unit comprises: a hollow case; a pair of pinch members disposed inside the case; an elastically deformable tube disposed between the pair of pinch members, which is connected to a conveying pipe through which a conveying object passes; and a drive device to drive the pair of pinch members either toward or away from the center of the tube. A tube inner space inside the tube and a tube outer space outside the tube but inside the case are hermetically isolated from each other, and the valve unit has a decompression device for reducing pressure of the tube outer space to a pressure lower than atmospheric pressure.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a valve unit and a pinch valve body. [Background technology]

[0002] For example, in conveying lines where negative pressure is maintained inside the piping to transport liquids, powders, and other materials used in the food industry, valves are installed to selectively suspend and resume conveyance. One type of valve, a butterfly valve, has a disk that oscillates inside a cylinder, but the seat ring can shift, preventing the disk from fully tightening, resulting in internal leakage. Another type of valve, a ball valve, has a sphere with a through hole that rotates inside a cylinder, but this can cause external air to be sucked in through the gap between the cylinder and the sphere, resulting in air trapping. In contrast, pinch valves close the flow path by mechanically squeezing or pinching a highly elastic tube such as silicone rubber from the outside to close the flow path inside the tube, so they do not suffer from the above-mentioned problems that tend to occur with butterfly valves and ball valves.

[0003] Since a typical pinch valve is installed in a line that includes pipes for carrying liquids or powders, it is required that the pinch valve not clog, that the inside of the device be easy to clean and have excellent sanitary properties, and that the device be easy to disassemble and assemble.

[0004] A known pinch valve, for example, is one that includes a pair of pinch levers that are arranged to swing freely outside the center of a tube and a means for driving the pair of pinch levers in a direction that pinches the tube between them (see Patent Document 1). By pinching the tube with the pinch levers, the inner circumference of the tube is narrowed, thereby stopping the transport of liquid or powder. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2016-70302 Summary of the Invention [Problem to be solved by the invention]

[0006] The tube used in a pinch valve is compressed from the outer periphery by the pinch lever, causing elastic deformation and squeezing the inner periphery. Therefore, the material and thickness of the tube are selected so that the tube is relatively easy to deform.

[0007] In order to facilitate the smooth transport of liquids or powders, the inside of the pipe connected to the tube is kept under negative pressure downstream, which also creates a negative pressure on the inner circumferential side of the tube connected to the pipe. In contrast, in a typical pinch valve, the outer circumferential side of the tube is at atmospheric pressure, so the differential pressure between atmospheric pressure and negative pressure acts on the circumferential wall of the tube. This differential pressure can cause the tube to collapse even without compression by the pinch lever, potentially preventing the transport of liquids or powders. One solution to this problem is to use a tube made of a material or with a wall thickness that is more easily deformed so that it can withstand the differential pressure between atmospheric pressure and negative pressure. However, this requires an increased driving force of the pinch lever to crush the tube, which increases costs and is counter to energy conservation.

[0008] An object of the present invention is to provide a valve unit and a pinch valve body that are low cost, energy efficient, and capable of smoothly transporting objects. [Means for solving the problem]

[0009] In order to achieve the above object, the valve unit of the present invention comprises: A hollow case and a pair of pinch members disposed within the case; an elastically deformable tube connected to a conveying pipe through which the conveyed object passes and disposed between the pinch members; a driving device that drives the pair of pinch members in a direction toward the center of the tube or in a direction away from the center of the tube, an inner-tube space inside the tube and an outer-tube space outside the tube and inside the case are airtightly separated, This is achieved by providing a pressure reducing device that reduces the pressure in the space outside the tube below atmospheric pressure.

[0010] In order to achieve the above object, the pinch valve body of the present invention comprises: A hollow case and a pair of pinch members disposed within the case; an elastically deformable tube connected to a conveying pipe through which the conveyed object passes and disposed between the pinch members; a driving device that drives the pair of pinch members in a direction toward the center of the tube or in a direction away from the center of the tube; a connector connectable to a pressure reducing device, an inner-tube space inside the tube and an outer-tube space outside the tube and inside the case are airtightly separated, the space outside the tube communicates with the outside only via the connector; This is achieved by the pressure reducing device being capable of reducing the pressure in the space outside the tube below atmospheric pressure via the connector. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a valve unit and a pinch valve body that are low cost, energy efficient, and capable of smoothly transporting an object to be transported. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of a transfer system incorporating a valve unit according to the first embodiment. [Figure 2]FIG. 2 is a front view of the pinch valve body of the valve unit, with the internal configuration shown by the dashed line, in the valve open state. [Figure 3] FIG. 3 is a front view of the pinch valve body of the valve unit, with the internal configuration shown by the dashed dotted line, showing the valve in a closed state. [Figure 4] FIG. 4 is a side view of the valve unit shown in a state where it is connected to a pipe. [Figure 5] FIG. 5 is a perspective view of the tube. [Figure 6] FIG. 6 is a side view showing the valve unit according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] (Conveyor system configuration) Hereinafter, a transfer system including a valve unit according to this embodiment will be described with reference to the drawings. FIG. 1 is a schematic diagram of a transfer system incorporating the valve unit of this embodiment.

[0014] In Figure 1, a first tank T1 capable of storing the transported material FL and a first valve unit 100 are connected by a transport pipe 201, the first valve unit 100 and a second tank T2 capable of storing the transported material FL are connected by a transport pipe 202, the second tank T2 and a second valve unit 100' are connected by a transport pipe 203, and the second valve unit 100' and a third tank T3 capable of storing the transported material FL are connected by a transport pipe 204.

[0015] The interior of the second tank T2 is connected to a negative pressure pump 210, and the interior of the third tank T3 is connected to a negative pressure pump 220. In this embodiment, the transfer pipes 201 to 204 basically have the same configuration. Furthermore, both the first valve unit 100 and the second valve unit 100' can selectively be in an open state or a closed state.

[0016] (Transport system operation) The operation of the conveying system will be described below. Here, the object FL to be conveyed is assumed to be a fluid (including a gel-like substance), powder, or gas (including air). When the object FL to be conveyed is conveyed from the first tank T1 to the second tank T2, the second valve unit 100' is closed and the first valve unit 100 is open. Furthermore, when the negative pressure pump 210 is operated to create a negative pressure inside the second tank T2, the pressure inside the conveying pipe 202 and the conveying pipe 201 is also negative via the open first valve unit 100, and as a result, the object FL is conveyed from the first tank T1 to the second tank T2 via the conveying pipes 201 and 202.

[0017] Furthermore, when the object FL is transferred from the second tank T2 to the third tank T3, the first valve unit 100 is closed and the second valve unit 100' is open. Furthermore, when the negative pressure pump 220 is operated to create a negative pressure inside the third tank T3, the pressure inside the transfer pipe 204 and the transfer pipe 203 is also negative via the open second valve unit 100', and the object FL is transferred from the second tank T2 to the third tank T3 via the transfer pipes 203 and 204. Similarly, the object FL can be transferred sequentially between multiple tanks.

[0018] In this embodiment, negative pressure pumps 210 and 220 are used to create negative pressure in the conveying pipes 202 and 204 downstream of the valve units 100 and 100', but the means for creating negative pressure in the conveying pipes are not limited to these, and negative pressure in the pipes can also be achieved using, for example, a powder vacuum conveyor, a liquid delivery pump, a cyclone (centrifuge), a vacuum dryer, a spray dryer, etc.

[0019] Since the first valve unit 100 and the second valve unit 100' basically have a common configuration, the first valve unit 100 will be mainly described here, and a description of the second valve unit 100' will be omitted.

[0020] (First embodiment) Figures 2 and 3 are front views of the pinch valve body 101 of the valve unit 100, with the internal configuration shown by dashed lines, with Figure 2 showing the valve in an open state and Figure 3 showing the valve in a closed state. Figure 4 is a side view of the valve unit 100, and schematically shows the related parts with the tube 130 connected to the upstream conveying pipe 201 and the downstream conveying pipe 202.

[0021] 4, the valve unit 100 includes a pinch valve body 101, a pressure sensor 102, a suction device 103, and a control device 104 electrically connected to the pressure sensor 102 and the suction device 103. In this embodiment, the pressure sensor 102, the suction device 103, and the control device 104 constitute a pressure reducing device.

[0022] First, a description will be given of the pinch valve body 101. In Figures 2 and 3, the pinch valve body 101 has a driving part 110, a driven part 120, and a tube .

[0023] The drive unit 110 has a cylindrical drive case 111 with a top, a bottom plate 112 that closes the bottom surface of the drive case, a piston plate 113 that divides the interior of the drive case 111 into an upper space A and a lower space B, and a drive shaft 114 that is connected to the underside of the piston plate 113. The drive shaft 114 passes through a through-hole formed in the bottom plate 112 and protrudes outside (downward) of the drive case 111. The piston plate 113 and the drive shaft 114 form a drive source.

[0024] The first connector 115 is connected to a hole formed in the top of the drive case 111, allowing air to enter and be exhausted into the upper space A through the first connector 115. The second connector 116 is connected to a hole formed in the side of the drive case 111, allowing air to enter and be exhausted into the lower space B through the second connector 116. For example, a pressure pump (not shown) is connected to the first connector 115 and the second connector 116. Note that in this embodiment, the drive unit 110 uses an air-powered drive source as an example, but this is not limited thereto and includes, for example, a drive unit using an electrically powered drive source. Furthermore, a mechanism for manually displacing a pair of pinch members 123 and 124 (described later) relative to each other is also included in the drive unit, in which case the drive source is human power from an operator.

[0025] The driven part 120 has a hollow driven case (also simply referred to as a case) 121, a link mechanism 122 installed in the driven case 121, and a pair of pinch members 123 and 124 that can be moved up and down by the link mechanism 122. The link mechanism 122 and the drive source constitute a drive device.

[0026] The driven case 121 is formed hollow by forming two curved parts by pressing a metal plate, such as stainless steel, and then assembling the pinch members 123 and 124 and the link mechanism 122. The edges of the curved parts are then faced to each other and joined at a weld W (FIG. 4). This results in a lightweight, highly rigid driven case 121. The open upper end of the driven case 121 is welded to the bottom plate 112 of the driving case 111. The central portions of the front and back of the driven case 121 are press-formed to form cylindrical portions 121a and 121b with open ends. Alternatively, separately manufactured cylindrical portions 121a and 121b may be welded to the driven case 121. As shown in FIG. 4, case flanges 121c and 121d protruding radially outward are formed at the protruding ends of the cylindrical portions 121a and 121b.

[0027] Link mechanism 122 has a so-called pantograph shape, with links 122a to 122d of equal length each pivotally connected at both ends to adjacent links. The connecting portion of upper links 122a and 122b is connected to the center of pinch member 123, to which the lower end of drive shaft 114 is pivotally connected.

[0028] On the other hand, the connecting portions of the lower links 122c and 122d are connected to the center of a pinch member 124 that is pivotally fixed to the driven case 121. A tube 130 is disposed inside the link mechanism 122 and between the pinch members 123 and 124.

[0029] 5 is a perspective view of the tube 130. The tube 130 comprises a cylindrical tube body 131 and flange portions 133 and 134 formed on both longitudinal ends of the tube body 131 and protruding radially outward, and may be, for example, a full bore tube or a reducer bore tube.

[0030] The tube body 131 is a cylindrical member having a uniform wall thickness. Flange portions 133 and 134 are integrally formed on both ends of the tube body 131 in the longitudinal direction.

[0031] In the tube 130, the tube body 131 and the flange portions 133 and 134 can all be formed from an elastically deformable material such as silicone rubber.

[0032] Because tube 130 is easily elastically deformed, it can be crushed using a jig, passed through one cylindrical portion 121a, and pulled out from the other cylindrical portion 121b, and then the jig can be removed to assemble it into driven case 121. At this time, tube main body 131 is held between pinch members 123 and 124.

[0033] When tube 130 is assembled to driven case 121, both ends of tube body 131 protrude outward from cylindrical portions 121a, 121b. At this time, the internal space of tube 130 is maintained in a state independent from the space within driven case 121. The internal space of tube 130 is referred to as the "intra-tube space," and the space outside tube 130 and inside driven case 121 is referred to as the "extra-tube space," with the intra-tube space and the extra-tube space being airtightly independent (not communicating with each other).

[0034] As shown in Figure 4, when the conveying pipes 202, 201 are connected to the pinch valve body 101 opposite the cylindrical portions 121a, 121b, the flat end faces of the case flanges 121c, 121d and the flat end faces of the pipe flanges 202a, 201a of the conveying pipes 202, 201 are forced close to each other by clamps (not shown), with the flanges 134, 133 of the tube 130 interposed between them. As a result, the flanges 133, 134 are sandwiched and compressed between the case flanges 121c, 121d and the pipe flanges 201a, 202a, and are in contact around their entire circumference, forming a seal that prevents leakage of the conveyed goods FL and the like from the joint. At the same time, the space outside the tube is isolated from the atmospheric pressure.

[0035] 4, a third connector 125 is connected to a hole formed in the side of the driven case 121, and air can enter and be exhausted into the driven case 121 via the third connector 125. Air can be exchanged between the inside of the driven case 121 and the outside only via the third connector 125. The third connector 125 is connected to a suction device 103 via a pipe 105. The suction device 103 may be, for example, a vacuum pump or an ejector.

[0036] Furthermore, a pressure sensor 102 is attached to the downstream conveying pipe 202 via a detection pipe 106, and the pressure sensor 102 detects the pressure inside the conveying pipe 202 and outputs a corresponding signal to the control device 104. The control device 104 controls the drive of the suction device 103 according to the pressure detected by the pressure sensor 102, thereby sucking the inside of the driven case 121 and adjusting it to a predetermined pressure.

[0037] (Pinch valve body operation) Next, we will explain the operation of pinch valve main body 101. When air is pressurized and sent from a pressure pump (not shown) via first connector 115 to upper space A in drive case 111 and second connector 116 is opened, the air pressure in upper space A rises and pushes piston plate 113 downward. This causes drive shaft 114 to move downward together with piston plate 113, pressing link mechanism 122 downward, causing the connecting portion of links 122a and 122b to move downward, which in turn displaces pinch member 123 downward.

[0038] On the other hand, since the pinch member 124 does not move in the vertical direction, the pinch members 123 and 124 move relative to each other toward the center of the tube body 131, crushing the tube body 131 into a plate-like shape, thereby preventing the passage of the transported goods FL, resulting in a so-called closed valve state (Figure 3).

[0039] In response to this, when air is pressurized and sent from a pressure pump (not shown) via second connector 116 to lower space B within drive case 111 and first connector 115 is opened, the air pressure in lower space B rises and pushes piston plate 113 upward. This causes drive shaft 114 to move upward together with piston plate 113, pulling link mechanism 122 upward, causing the connecting portion of links 122a and 122b to move upward, and accordingly pinch member 123 to be displaced upward.

[0040] Since the pinch member 124 does not move in the vertical direction, when the pinch members 123 and 124 move relative to each other so as to move away from the center of the tube main body 131, the gap between them widens, and the tube main body 131 is released from the external force and expands into a cylindrical shape due to the elastic force of the tube main body 131, thereby allowing the transported object FL to pass through, resulting in a so-called open valve state (Figure 2).

[0041] During transport, as described above, the inside of tube 130 is also subjected to approximately the same negative pressure due to suction from transport pipe 202 connected downstream of pinch valve body 101. Because tube 130 is made of an elastically deformable material, it has relatively low rigidity. If the inside of driven case 121, which is outside tube 130, is at atmospheric pressure, the negative pressure inside tube 130 will cause tube body 131 to be crushed due to the pressure difference between the inside and outside, which could hinder the transport of the object FL.

[0042] In contrast, according to the present embodiment, the control device 104 receives a pressure signal from the pressure sensor 102 that detects the pressure inside the downstream conveying pipe 202, and outputs a corresponding drive signal to the suction device 103. The suction device 103 operates under the control of the drive signal, sucking air from the driven case 121 via the third connector 125 and preferably making the pressure inside the driven case 121 the same as the pressure inside the downstream conveying pipe 202. This makes the internal and external pressures on the peripheral wall of the tube main body 131 approximately equal, preventing the tube main body 131 from collapsing due to a difference in air pressure and preventing the opening and closing operation of the pinch valve main body 101 from being hindered. According to the present embodiment, the tube 130 can be formed from a low-rigidity material, thereby eliminating the need to increase the drive pressure of the drive unit 110. This makes it possible to provide a valve unit 100 that is low-cost, energy-efficient, and capable of smoothly conveying the object FL.

[0043] According to the results of investigations by the present inventors, it has been found that the pressure difference between the inside and outside of tube main body 131 does not necessarily have to be zero, and that if it is 0 to 15 kPa, the operation of pinch valve main body 101 is not inhibited.

[0044] Therefore, as a modification of the above embodiment, the suction device 103 may be operated as a standalone pressure reducing device to maintain a constant negative pressure (for example, atmospheric pressure -15 kPa) inside the driven case 121 without providing the pressure sensor 102 and the control device 104. Also, the suction device 103 may be incorporated into the pinch valve body 101 as an integrated unit.

[0045] (Second embodiment) FIG. 6 is a view similar to FIG. 4 showing a valve unit 100A according to a second embodiment. The pinch valve body 101 has the same configuration as that of the first embodiment, and therefore will not be described again. The conveying pipes 201 and 202 are also the same as those of the first embodiment. The valve unit 100A can be incorporated into the conveying system of FIG. 1, as in the first embodiment.

[0046] In this embodiment, a pressure sensor, a suction device, and a control device are not provided, and a third connector 125 is connected to the downstream transfer pipe 202 via a communication pipe 126. The communication pipe 126, which constitutes the pressure reducing device, has a filter 127 midway along the pipe.

[0047] For example, when powder is being transported as the transported object, when the downstream conveying pipe 202 is made negative pressure, the same negative pressure is created inside the driven case 121 via the communicating pipe 126 and the third connector 125. As a result, similar to the first embodiment, the tube body 131 will not be crushed due to a difference in air pressure, and the opening and closing valve action of the pinch valve body 101 will not be hindered. The filter 127 has the function of preventing powder in the conveying pipe 202 from entering the driven case 121 and allowing only air to pass through.

[0048] It should be noted that the present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment is described in order to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to an embodiment having all of the described configurations.

[0049] This specification includes the disclosure of the following inventions. (First aspect) A hollow case and a pair of pinch members disposed within the case; an elastically deformable tube connected to a conveying pipe through which the conveyed object passes and disposed between the pinch members; a driving device that drives the pair of pinch members in a direction toward the center of the tube or in a direction away from the center of the tube, an inner-tube space inside the tube and an outer-tube space outside the tube and inside the case are airtightly separated, A pressure reducing device is provided to reduce the pressure in the space outside the tube below atmospheric pressure. A valve unit characterized by:

[0050] (Second aspect) The pressure reducing device reduces the pressure in the tube external space so that the pressure difference between the tube internal space and the tube external space is 0 to 15 kPa. The valve unit according to the first aspect,

[0051] (Third aspect) The pressure reducing device includes a pressure sensor that detects the pressure in the conveying pipe connected downstream of the tube, a suction device that sucks the space outside the tube inside the case, and a control device that drives and controls the suction device based on the pressure detected by the pressure sensor. The valve unit according to the first or second aspect, characterized in that:

[0052] (Fourth aspect) the pressure reducing device has a communication pipe, and the communication pipe communicates between a conveying pipe connected downstream of the tube and a space outside the tube inside the case. The valve unit according to the first or second aspect, characterized in that:

[0053] (Fifth aspect) The communication pipe has a filter that allows only air to pass through. A valve unit according to a fourth aspect, characterized in that:

[0054] (Sixth aspect) The flange portions formed on both ends of the tube are sandwiched between the case and flange portions of conveying pipes connected to the downstream and upstream sides of the tube. The valve unit according to any one of the first to fifth aspects, characterized in that:

[0055] (Seventh aspect) the drive device includes a link mechanism that is deformed by a driving force transmitted from a drive source; One of the pinch members is connected to the link mechanism, and the other of the pinch members is connected to the case. The valve unit according to any one of the first to sixth aspects, characterized in that:

[0056] (Eighth aspect) The link mechanism is composed of four links of equal length, and both ends of each link are pivotally connected to an adjacent link. A seventh aspect of the valve unit is characterized in that:

[0057] (Ninth aspect) The case is formed by joining a pair of pressed metal plate parts by welding. A valve unit according to a ninth aspect, characterized in that:

[0058] (Tenth aspect) A hollow case and a pair of pinch members disposed within the case; an elastically deformable tube connected to a conveying pipe through which the conveyed object passes and disposed between the pinch members; a driving device that drives the pair of pinch members in a direction toward the center of the tube or in a direction away from the center of the tube; a connector connectable to a pressure reducing device, an inner-tube space inside the tube and an outer-tube space outside the tube and inside the case are airtightly separated, the space outside the tube communicates with the outside only via the connector; The pressure in the space outside the tube can be reduced below atmospheric pressure via the connector by the pressure reducing device. A pinch valve body characterized by: [Explanation of symbols]

[0059] 100, 100', 100A valve unit 101 Pinch valve body 102 Pressure Sensor 103 Suction device 104 Control device 110 Drive unit 111 Drive case 120 Driven part 121 Driven Case 126 Communication piping 127 filters 130 tubes

Claims

1. A hollow case and A pair of pinch members disposed within the case; an elastically deformable tube connected to a conveying pipe through which the conveyed object passes and disposed between the pinch members; a driving device that drives the pair of pinch members in a direction toward the center of the tube or in a direction away from the center of the tube, an inner-tube space inside the tube and an outer-tube space outside the tube and inside the case are airtightly separated, A pressure reducing device is provided to reduce the pressure in the space outside the tube below atmospheric pressure. A valve unit characterized by:

2. The pressure reducing device reduces the pressure in the tube outer space so that the pressure difference between the tube inner space and the tube outer space is 0 to 15 kPa. The valve unit according to claim 1 .

3. The pressure reducing device includes a pressure sensor that detects the pressure in the conveying pipe connected downstream of the tube, a suction device that sucks the space outside the tube inside the case, and a control device that drives and controls the suction device based on the pressure detected by the pressure sensor. The valve unit according to claim 1 .

4. the pressure reducing device has a communication pipe, and the communication pipe communicates between a conveying pipe connected downstream of the tube and a space outside the tube inside the case. The valve unit according to claim 1 .

5. The communication pipe has a filter that allows only air to pass through. The valve unit according to claim 4 .

6. The flange portions formed on both ends of the tube are sandwiched between the case and flange portions of conveying pipes connected to the downstream and upstream sides of the tube. The valve unit according to claim 1 .

7. the drive device includes a link mechanism that is deformed by a driving force transmitted from a drive source; One of the pinch members is connected to the link mechanism, and the other of the pinch members is connected to the case. The valve unit according to claim 1 .

8. The link mechanism is composed of four links of equal length, and both ends of each link are pivotally connected to an adjacent link. The valve unit according to claim 7 .

9. The case is formed by joining a plurality of parts made of pressed metal plates by welding. The valve unit according to claim 1 .

10. A hollow case and A pair of pinch members disposed within the case; an elastically deformable tube connected to a conveying pipe through which the conveyed object passes and disposed between the pinch members; a driving device that drives the pair of pinch members in a direction toward the center of the tube or in a direction away from the center of the tube; a connector connectable to a pressure reducing device, an inner-tube space inside the tube and an outer-tube space outside the tube and inside the case are airtightly separated, the space outside the tube communicates with the outside only via the connector; The pressure in the space outside the tube can be reduced below atmospheric pressure via the connector by the pressure reducing device. A pinch valve body characterized by:

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