JP2018197509A - Check valve for diaphragm pump, and diaphragm pump - Google Patents

Abstract

To provide a check valve for diaphragm pump which can suppress breakage of a diaphragm.SOLUTION: A check valve 2 includes: a valve part 60 having a valve body 61; a cylindrical casing 50 having a valve seat 51; and a spring 64 for energizing the valve part 60 so that the valve body 61 comes into contact with the valve seat 51. The casing 50 includes: a first cylinder part 52 including the valve seat 51; a second cylinder part 53 connected to one end of the first cylinder part 52; and a third cylinder part 54 connected to the other end of the first cylinder part 52. The first cylinder part 52 is formed by a flexible material. Even when solid particles P are bitten between the valve body 61 and the valve seat 51, by the valve seat 51 being deformed, the valve body 61 and the valve seat 51 are adhered to each other. As a result, a closing delay of the check valve 2 can be suppressed, generation of a peak hydraulic pressure can be suppressed, and breakage of a diaphragm 30 can be suppressed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a check valve for a diaphragm pump and a diaphragm pump. More specifically, the present invention relates to a check valve provided on the suction side of a hydraulic diaphragm pump used for transferring slurry, and a diaphragm pump including the check valve.

  The diaphragm pump is a pump that transfers fluid by periodically changing the volume of the suction chamber by the reciprocating motion of the diaphragm. Since the amount of increase / decrease in the volume of the suction chamber is always constant, the fluid can be quantitatively transferred. Therefore, the diaphragm pump is used in a field where a quantitative transfer of fluid is required. Examples of such fields include the chemical industry field in which chemical reaction treatment is continuously performed, and the water treatment field in which quantitative chemical solution injection is required.

  Compared to a spiral pump having an impeller that rotates in a casing, the diaphragm pump has a structure in which backflow is unlikely to occur. Therefore, the diaphragm pump has a high self-priming capability and a high discharge pressure. Because of these characteristics, the diaphragm pump is also used for transferring a liquid having a high viscosity or a slurry having a high solid content.

  Since the diaphragm is a resin film, it is relatively easy to break. If the diaphragm is perforated or cracked, the fluid to be transferred enters the hydraulic chamber. If the operation is continued in this state, the internal structure of the diaphragm pump is damaged. In particular, when the fluid to be transferred is corrosive and wearable, the internal structure tends to be damaged.

  Patent Document 1 discloses a damage detection device that detects that a diaphragm is damaged. This breakage detection device can detect the damage only when the diaphragm is broken. Therefore, the diaphragm cannot be prevented from being damaged.

Japanese Patent Laying-Open No. 2015-40517

  The inventor of the present application investigated the cause of the diaphragm damage. As a result, solid particles contained in the slurry get caught between the valve body of the suction side check valve of the diaphragm pump and the valve seat, causing a delay in closing the check valve, which causes abnormal hydraulic pressure in the hydraulic chamber. It has been found that a peak hydraulic pressure is generated, which causes damage to the diaphragm.

  In view of the above circumstances, an object of the present invention is to provide a check valve for a diaphragm pump and a diaphragm pump that can suppress damage to the diaphragm.

A check valve for a diaphragm pump according to a first aspect of the present invention is a check valve provided on the suction side of a hydraulic diaphragm pump for transferring slurry, and a cylindrical casing having a valve portion and a valve seat. And a spring that urges the valve portion so that the valve body comes into contact with the valve seat, and the casing includes a first tube portion including the valve seat, and one end of the first tube portion. It has a 2nd cylinder part connected and a 3rd cylinder part connected to the other end of the 1st cylinder part, and the 1st cylinder part is formed with a flexible material, It is characterized by the above-mentioned. .
A check valve for a diaphragm pump according to a second invention is characterized in that, in the first invention, the flexible material is a resin.
A check valve for a diaphragm pump according to a third invention is characterized in that, in the first invention, the flexible material is a polyether ether ketone resin or a fluororesin.
A check valve for a diaphragm pump according to a fourth aspect of the present invention is the first, second or third aspect, wherein the first cylindrical portion, the second cylindrical portion, and the third cylindrical portion are connected to each other. It is characterized by being fastened by a fastening member that applies a fastening force in the axial direction.
A diaphragm pump according to a fifth aspect of the invention includes the check valve according to the first, second, third, or fourth aspect of the invention.
A diaphragm pump according to a sixth invention is characterized in that, in the fifth invention, the slurry contains a mixed sulfide containing nickel and cobalt, and a discharge side of the diaphragm pump is connected to an autoclave through a pipe.

According to the first invention, even if solid particles contained in the slurry are caught between the valve body and the valve seat, the valve body formed of a flexible material is deformed so that the valve body and the valve seat are in close contact with each other. To do. As a result, the delay in closing the check valve can be suppressed, the occurrence of peak hydraulic pressure where the hydraulic pressure in the hydraulic chamber of the diaphragm pump becomes abnormally high can be suppressed, and the diaphragm can be prevented from being damaged.
According to the second aspect of the invention, since the first cylindrical portion is made of resin, the solidity of the valve seat is sufficient when the solid particles are caught between the valve body and the valve seat.
According to the third invention, since the first tube portion is formed of the polyether ether ketone resin or the fluororesin, it has resistance to abrasion.
According to the fourth aspect of the invention, the casing can be disassembled by releasing the fastening of the fastening member, so that the first tube part can be easily replaced.
According to the fifth aspect, the diaphragm can be prevented from being damaged, so that the maintenance cost of the diaphragm pump can be reduced.
According to the sixth aspect of the invention, since the diaphragm can be prevented from being damaged, the stop time of the process in which the diaphragm pump is used can be shortened.

It is a longitudinal cross-sectional view of the diaphragm pump which concerns on 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the suction side check valve used for the same diaphragm pump. It is the elements on larger scale near the contact surface of the suction side check valve. It is explanatory drawing of the equipment of a nickel sulfate manufacturing process. It is a longitudinal cross-sectional view of the conventional check valve. It is a schematic diagram which shows operation | movement of a diaphragm pump. (A) is a schematic diagram when the diaphragm reaches the forward end position. FIG. 5B is a schematic diagram when the diaphragm reaches the backward movement initial position. FIG. 6C is a schematic diagram when the diaphragm reaches the backward end position. FIG. 4D is a schematic diagram when the diaphragm reaches the forward movement initial position. It is a graph which shows the oil pressure waveform in the oil pressure room at the time of normal. (A) is a graph showing one cycle of the hydraulic waveform in the hydraulic chamber at the time of abnormality. (B) The figure is the graph which expanded the area | region R in the graph of (A) figure. It is a graph which shows the oil pressure waveform in the oil pressure room at the time of abnormality.

Next, an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
The diaphragm pump according to the first embodiment of the present invention transfers slurry containing solid particles, and its use is not particularly limited. Hereinafter, a diaphragm pump used for transferring a slurry containing nickel / cobalt mixed sulfide to an autoclave in a process for producing nickel sulfate will be described as an example.

(Nickel sulfate manufacturing process)
A mixed sulfide (MS) containing nickel and cobalt is used as a raw material for nickel sulfate. Nickel-cobalt mixed sulfide contains nickel ions and cobalt ions after high pressure acid leaching (HPAL: High Pressure Acid Leaching) of nickel oxide ore of low nickel grade and removing impurities such as iron from pressurized acid leaching solution. It is obtained by a wet sulfidation reaction in which hydrogen sulfide gas is blown into the leachate. The main component of the nickel / cobalt mixed sulfide is a sulfide such as NiS.

  In the repulping process, the nickel / cobalt mixed sulfide is repulped with water or the like to form a slurry. In the repulping process, a solid powdered nickel / cobalt mixed sulfide is put into a repulping bath, mixed with water and stirred to produce a slurry.

  The slurry is charged into an autoclave and subjected to pressure leaching. As shown in FIG. 4, the slurry produced in the repulping process is temporarily stored in the initial liquid tank 101. The starting liquid tank 101 is connected to the autoclave 104 via the upstream pipe 102, the diaphragm pump 1, and the downstream pipe 103. The suction side of the diaphragm pump 1 is connected to the starting liquid tank 101 via the upstream pipe 102, and the discharge side of the diaphragm pump 1 is connected to the autoclave 104 via the downstream pipe 103. By driving the diaphragm pump 1, the slurry in the initial liquid tank 101 is transferred to the autoclave 104.

  In the pressure leaching step, nickel and cobalt contained in the mixed sulfide are leached by the high pressure air by the autoclave 104. For example, the solid content concentration of the slurry charged into the autoclave 104 is 200 to 300 g / L, and the flow rate is 50 to 100 L / min. The temperature in the autoclave 104 is 150 to 220 ° C., and the pressure is 1.7 to 2.3 MPa as a gauge pressure.

  From the autoclave 104, a pressure leachate which is a mixed aqueous solution of nickel sulfate and cobalt sulfate is discharged. The pressurized leachate is reduced in pressure and cooled, then supplied to the next step, and used for the production of nickel sulfate.

(Diaphragm pump)
Next, the structure of the diaphragm pump 1 will be described.
The diaphragm pump 1 of the present embodiment is a hydraulic diaphragm pump that is driven by hydraulic oil.

  As shown in FIG. 1, the diaphragm pump 1 includes a pump body 10. A pump cover 20 is fastened to the front surface (left side in FIG. 1) of the pump body 10. Between the pump main body 10 and the pump cover 20, the outer peripheral edge of a disk-shaped diaphragm 30 is fastened. The diaphragm 30 is a flexible film and is formed of a resin such as polytetrafluoroethylene or rubber.

  A hydraulic chamber 11 filled with hydraulic oil is formed inside the pump body 10. The hydraulic chamber 11 includes a diaphragm working chamber 11a, a piston working chamber 11b, and a flow path 11c that connects the diaphragm working chamber 11a and the piston working chamber 11b. Inside the pump cover 20 is formed a suction chamber 21 into which slurry, which is a fluid to be transferred, is sucked and sent. The hydraulic chamber 11 (diaphragm working chamber 11a) and the suction chamber 21 are separated by a diaphragm 30.

  The center portion of the diaphragm 30 is sandwiched between a pair of disks 31 and 32. A guide rod 33 is connected to the disk 32 on the hydraulic chamber 11 side. The guide rod 33 is passed through the shaft hole 34 and is slidable in the front and back direction of the diaphragm 30 (left and right direction in FIG. 1).

  A compression spring 35 is inserted into the guide rod 33. One end of the compression spring 35 is supported by a flange 36 formed at the rear end of the guide rod 33, and the other end is supported by a shoulder 37 formed in the pump body 10. The guide rod 33 is urged by the compression spring 35 in the direction of pulling the disks 31 and 32 toward the hydraulic chamber 11 (right direction in FIG. 1). Thereby, the diaphragm 30 is preloaded on the hydraulic chamber 11 side.

  A piston 40 is provided inside the pump body 10. The piston 40 includes a cylindrical piston head 41 and a piston rod 42 connected to the piston head 41. The piston head 41 is inserted into a cylindrical cylinder part 12 that constitutes a part of the side wall of the piston working chamber 11b, and is slidable along the axial direction of the cylinder part 12. The side surface of the piston head 41 and the inner wall of the cylinder part 12 are sealed in a liquid-tight manner.

  The piston 40 reciprocates by driving a drive unit (not shown). For example, the drive unit includes an electric motor, a crankshaft that rotates by driving the electric motor, and a connecting rod connected to the crankshaft. The connecting rod is connected to the piston rod 42.

  As the piston 40 reciprocates, the hydraulic pressure in the hydraulic chamber 11 rises and falls. More specifically, when the piston 40 moves forward (moves to the left in FIG. 1), the piston head 41 moves toward the inside of the hydraulic chamber 11 and the hydraulic pressure in the hydraulic chamber 11 increases. Conversely, when the piston 40 moves backward (moves to the right in FIG. 1), the piston head 41 moves toward the outside of the hydraulic chamber 11, and the hydraulic pressure in the hydraulic chamber 11 decreases.

  As the hydraulic pressure in the hydraulic chamber 11 rises and falls, the diaphragm 30 reciprocates. More specifically, when the hydraulic pressure in the hydraulic chamber 11 rises, the diaphragm 30 moves forward (moves toward the suction chamber 21 side). Conversely, when the hydraulic pressure in the hydraulic chamber 11 drops, the diaphragm 30 moves backward (moves toward the hydraulic chamber 11 side). Thus, the diaphragm 30 reciprocates due to the reciprocating motion of the piston 40.

  The suction side of the suction chamber 21 is connected to the secondary side of the suction side check valve 2 via the suction flow path 22. A suction port member 23 having a suction port is connected to the primary side of the suction side check valve 2. The suction side check valve 2 allows the flow of fluid from the suction port toward the suction chamber 21 and prevents the reverse flow.

  The primary side of the discharge side check valve 3 is connected to the discharge side of the suction chamber 21 via the discharge flow path 24. A discharge port member 25 having a discharge port is connected to the secondary side of the discharge side check valve 3. The discharge side check valve 3 allows the flow of fluid from the suction chamber 21 toward the discharge port and prevents the reverse flow.

  When the diaphragm 30 moves backward, the volume of the suction chamber 21 increases, and the fluid to be transferred is sucked into the suction chamber 21 from the suction port. At this time, the suction side check valve 2 opens to allow the flow of fluid. On the other hand, the discharge side check valve 3 is closed. The process in which the diaphragm 30 moves backward and the fluid to be transferred is sucked into the suction chamber 21 is referred to as a suction process.

  When the diaphragm 30 moves forward, the volume of the suction chamber 21 decreases, and the fluid in the suction chamber 21 is sent out from the discharge port. At this time, the discharge side check valve 3 opens to allow the flow of fluid. On the other hand, the suction side check valve 2 is closed. The process in which the diaphragm 30 moves forward and the fluid to be transferred is sent out from the suction chamber 21 is referred to as a sending process.

  In this way, the volume of the suction chamber 21 is increased or decreased by the reciprocating movement of the diaphragm 30, whereby the fluid to be transferred is sucked into the suction chamber 21 and sent out. As a result, the fluid to be transferred is transferred from the suction port (primary side) of the diaphragm pump 1 toward the discharge port (secondary side).

  A storage chamber 13 for storing hydraulic oil is formed inside the pump body 10. The hydraulic pressure in the storage chamber 13 is about atmospheric pressure. A pressure control valve 15 is provided in the flow path 14 connecting the hydraulic chamber 11 and the storage chamber 13. When the hydraulic pressure in the hydraulic chamber 11 becomes higher than the set pressure of the pressure control valve 15, the pressure control valve 15 is opened and excess hydraulic oil in the hydraulic chamber 11 escapes to the storage chamber 13. Thereby, it can suppress that excessive hydraulic pressure generate | occur | produces in the hydraulic chamber 11. FIG.

  The hydraulic chamber 11 and the storage chamber 13 are connected by another flow path (not shown), and a refill valve (not shown) is provided in the flow path. When the hydraulic pressure in the hydraulic chamber 11 becomes lower than the set pressure (about atmospheric pressure) of the refill valve, the refill valve is opened and the hydraulic oil in the storage chamber 13 is refilled into the hydraulic chamber 11. Thereby, when the hydraulic oil in the hydraulic chamber 11 decreases due to leakage loss, the shortage is compensated.

  The pump body 10 is formed with pores 16 that connect the hydraulic chamber 11 and the outside of the pump body 10. An oil pressure gauge 17 is provided at the end of the pore 16 on the outside of the pump body 10. The oil pressure in the hydraulic chamber 11 can be measured by the oil pressure gauge 17.

(Conventional check valve)
Next, the structure of a conventional check valve 200 used as the suction-side check valve 2 and the discharge-side check valve 3 will be described. The check valve 200 is of a type called a cone valve.

  As shown in FIG. 5, the check valve 200 includes a casing 50. The casing 50 is formed in a cylindrical shape so that a fluid flows inside. A valve unit 60 is provided inside the casing 50. The valve unit 60 includes a disc-shaped valve body 61 projecting in the radial direction of the casing 50, and a valve rod 62 provided on the valve body 61.

  A support member 63 that slidably supports the valve rod 62 is provided inside the casing 50. The valve member 60 is supported by the support member 63 so that the central axis thereof coincides with the central axis of the casing 50. Further, the valve part 60 is slidable along the central axis of the casing 50. The support member 63 has a plurality of holes so as not to hinder the flow of fluid inside the casing 50.

  A compression spring 64 is inserted into the valve stem 62. One end of the compression spring 64 is supported by the support member 63, and the other end is supported by a flange portion 65 provided at the rear end portion of the valve rod 62. The valve portion 60 is urged in one direction (downward in FIG. 5) by the compression spring 64.

  A part of the inner wall of the casing 50 projects radially inward. This overhanging portion is a valve seat 51 that contacts the valve body 61. The compression spring 64 urges the valve portion 60 so that the valve body 61 contacts the valve seat 51.

  The valve seat 51 has an annular contact surface 51a with which the valve body 61 contacts. The valve body 61 is in surface contact with the contact surface 51 a of the valve seat 51. When the valve body 61 contacts the valve seat 51, the flow path in the casing 50 is closed.

  A valve body 61 and a valve seat 51 are arranged along the central axis of the casing 50. The valve seat 51 side (the lower side in FIG. 5) is the primary side of the check valve 200. The valve body 61 side (the upper side in FIG. 5) is the secondary side of the check valve 200. The check valve 200 allows the flow of fluid from the primary side to the secondary side and prevents the reverse flow.

  The casing 50 and the valve part 60 are entirely made of metal such as 25% Cr cast steel, ceramics, or the like.

(Multiple diaphragm pump)
By the way, the diaphragm pump 1 has a structure in which the flow velocity is not constant and pulsation occurs. Further, the volume of the fluid discharged per cycle is limited by the volume of the suction chamber 21. Moreover, the period of reciprocation of the diaphragm 30 has a mechanical upper limit. Therefore, the diaphragm pump 1 is not suitable for transferring a large amount of fluid.

  In order to alleviate pulsation and enable a large amount of fluid to be transferred, a multiple diaphragm pump in which a plurality of unit pumps are connected has been devised. Here, the unit pump means a configuration having a function as a pump by itself. Specifically, the unit pump has the configuration shown in FIG. 1, and includes a suction chamber 21, a hydraulic chamber 11, a diaphragm 30, a piston 40, a suction side check valve 2, a discharge side check valve 3, and other members. Is provided.

  A plurality of unit pumps constituting the multiple diaphragm pump operate in synchronization. Specifically, the drive unit for reciprocating the piston 40 of each unit pump is shared. A piston rod 42 of each unit pump is connected to each of a plurality of connecting rods constituting the drive unit. The plurality of unit pumps are driven in a state in which the phase of the reciprocating motion of the diaphragm 30 is shifted by a predetermined amount. For example, in the case of a triple diaphragm pump, the three unit pumps are driven with phases shifted by 120 degrees.

  As shown in FIG. 4, in the case of the multiple diaphragm pump 1, a suction pipe 105 that connects the suction ports of the unit pumps in parallel is provided. Moreover, the discharge piping 106 which connects the discharge port of each unit pump in parallel is provided. The fluid supplied from the upstream pipe 102 is branched by the suction pipe 105 and supplied to each unit pump. The fluid discharged from each unit pump is merged in the discharge pipe 106 and supplied to the downstream pipe 103.

  In addition, the diaphragm pump 1 of this embodiment may be a single diaphragm pump having only one unit pump, or may be a multiple diaphragm pump having a plurality of unit pumps.

(Diaphragm pump operation)
Next, the operation of the diaphragm pump 1 and the hydraulic waveform in the hydraulic chamber 11 will be described.
FIG. 6 schematically shows the position of the diaphragm 30 and the open / close states of the suction-side check valve 2 and the discharge-side check valve 3. FIG. 7 shows a graph of the hydraulic waveform in the hydraulic chamber 11. In the graph of FIG. 7, the horizontal axis represents time, and the vertical axis represents the hydraulic pressure in the hydraulic chamber 11.

  As shown in FIG. 6A, the position where the diaphragm 30 reaches the final end of the forward movement is referred to as the forward movement end position. At this time, both the suction side check valve 2 and the discharge side check valve 3 are closed. The hydraulic pressure in the hydraulic chamber 11 when the diaphragm 30 reaches the forward end position corresponds to the point A in the graph of FIG.

  As shown in FIG. 6B, a position where the diaphragm 30 starts to move backward is referred to as a backward movement initial position. At this time, the suction side check valve 2 is switched from the closed state to the open state. The discharge side check valve 3 remains closed. The hydraulic pressure in the hydraulic chamber 11 when the diaphragm 30 reaches the initial return position corresponds to a point B in the graph of FIG. From point A to point B, the hydraulic pressure in the hydraulic chamber 11 drops in a short time. The process from point A to point B is referred to as a hydraulic pressure lowering process.

  As shown in FIG. 6C, the position where the diaphragm 30 reaches the final end of the backward movement is referred to as the backward movement end position. At this time, the suction side check valve 2 switches from the open state to the closed state. The discharge side check valve 3 remains closed. The hydraulic pressure in the hydraulic chamber 11 when the diaphragm 30 reaches the backward end position corresponds to the point C in the graph of FIG. From the point B to the point C, the hydraulic pressure in the hydraulic chamber 11 is gradually lowered while the pressure is low. The process from the point B to the point C is a suction process in which the fluid to be transferred is sucked into the suction chamber 21.

  As shown in FIG. 6D, the position where the diaphragm 30 starts to move forward is referred to as the forward movement initial position. At this time, the discharge side check valve 3 is switched from the closed state to the open state. The suction side check valve 2 remains closed. The hydraulic pressure in the hydraulic chamber 11 when the diaphragm 30 reaches the forward movement initial position corresponds to a point D in the graph of FIG. From point C to point D, the hydraulic pressure in the hydraulic chamber 11 rises in a short time. The process from point C to point D is referred to as a hydraulic pressure increase process.

  The diaphragm 30 reaches the forward end position shown in FIG. As shown in FIG. 7, from point D to the next point A, the hydraulic pressure in the hydraulic chamber 11 remains high and gradually rises while drawing a gentle waveform close to a sine wave. The process from the point D to the next point A is a delivery process in which the fluid to be transferred is delivered from the suction chamber 21.

(Hydraulic waveform)
The inventor of the present application analyzed the hydraulic waveform in the hydraulic chamber 11 and obtained the following knowledge.
The hydraulic pressure in the hydraulic chamber 11 at normal time has a waveform as shown in FIG. In particular, in the hydraulic pressure increasing process (point C → point D), the hydraulic pressure in the hydraulic chamber 11 increases smoothly.

  As shown in FIG. 8A, in the initial stage of the hydraulic pressure increase process (from point C to point D), the increase in hydraulic pressure may be temporarily delayed. The graph of FIG. 8B is an enlarged view of the region R of the graph of FIG. The graph of FIG. 8B is an enlarged scale of the time axis (horizontal axis) compared to the graph of FIG. As can be seen from the graph of FIG. 8B, a slight delay period DP occurs in the increase of the hydraulic pressure. At this time, as shown in FIG. 8A, the hydraulic pressure waveform in the delivery process (from point D to point A) is disturbed compared to the normal time, for example, the wave period is shortened.

  The graph of FIG. 9 shows a hydraulic pressure waveform when the delay period DP is further increased. At this time, the hydraulic pressure waveform in the delivery process (from point D to point A) is further disturbed compared to the normal time. In addition, at the initial stage of the delivery process, a peak oil pressure is generated in which the oil pressure is abnormally high.

  When the peak hydraulic pressure is generated, a higher pressure load than expected is applied to the diaphragm 30. Therefore, the diaphragm 30 may be damaged if the peak hydraulic pressure is continuously generated.

The inventor of the present application estimates the cause of the delay period DP of the hydraulic pressure increase and the peak hydraulic pressure as follows.
When the slurry is transferred by the diaphragm pump 1, when the diaphragm 30 reaches the return end position and the suction side check valve 2 is switched from the open state to the closed state, the solid particles contained in the slurry are sucked into the suction side check valve 2. May be caught between the valve seat 51 and the valve body 61.

  In this case, the suction side check valve 2 is incompletely closed. When the diaphragm 30 moves forward in this state, the fluid in the suction chamber 21 flows backward through the gap between the valve seat 51 of the suction side check valve 2 and the valve body 61. As a result, the hydraulic pressure in the hydraulic chamber 11 does not increase, and a delay period DP occurs.

  When the solid particles caught between the valve seat 51 and the valve body 61 are caused to flow by the backflowed fluid or are crushed finely by the pressure acting between the valve seat 51 and the valve body 61, the suction side reverse The stop valve 2 is completely closed. Thereafter, the hydraulic pressure in the hydraulic chamber 11 increases.

  Under normal conditions, the suction-side check valve 2 is completely closed when the diaphragm 30 reaches the return end position. That is, when the piston 40 is at the bottom dead center on the return side and the kinetic energy is substantially zero, the suction side check valve 2 is closed. Therefore, the rapid increase in the hydraulic pressure in the hydraulic chamber 11 due to the suction side check valve 2 being closed does not occur.

  On the other hand, when solid particles are caught between the valve seat 51 and the valve body 61, the suction-side check valve 2 is completely closed when the diaphragm 30 moves forward from the return end position. That is, the suction side check valve 2 is closed when the piston 40 moves forward and the kinetic energy increases. Therefore, when the suction side check valve 2 is closed, the hydraulic pressure in the hydraulic chamber 11 rapidly increases. In this way, the suction-side check valve 2 is delayed in closing, which causes the hydraulic pressure waveform to be disturbed in the delivery process, and causes the peak hydraulic pressure when the delay period DP is long.

  Based on the above knowledge, the inventor of the present application forms the valve seat 51 of the suction side check valve 2 with a flexible material, so that even if solid particles are caught between the valve body 61 and the valve seat 51, It has been found that the valve seat 51 can be deformed to suppress the closing delay of the check valve 2.

(Suction side check valve)
Next, the structure of the suction side check valve 2 which is a characteristic part of the present embodiment will be described.
Hereinafter, the suction-side check valve 2 is simply referred to as a check valve 2.

  As shown in FIG. 2, the casing 50 of the check valve 2 is divided into three parts along the axial direction, and includes a first cylinder part 52, a second cylinder part 53, and a third cylinder part 54. Since the rest of the configuration is the same as that of the conventional check valve 200 shown in FIG. 5, the same reference numerals are assigned to the same members and the description thereof is omitted.

  The first tube portion 52 is a cylindrical member and includes a valve seat 51. The second cylindrical portion 53 is a cylindrical member, and is connected to one end (the upper end in FIG. 2) of the first cylindrical portion 52. The third cylindrical portion 54 is a cylindrical member, and is connected to the other end (lower end in FIG. 2) of the first cylindrical portion 52.

  The diameter of the first cylinder part 52 is set smaller than the diameters of the second cylinder part 53 and the third cylinder part 54. In addition, circular recesses are formed on the lower end surface of the second cylindrical portion 53 (end surface in contact with the first cylindrical portion 52) and the upper end surface of the third cylindrical portion 54 (end surface in contact with the first cylindrical portion 52), respectively. Has been. Both end portions of the first tube portion 52 are fitted in the recesses of the second tube portion 53 and the third tube portion 54. Thereby, the 1st cylinder part 52, the 2nd cylinder part 53, and the 3rd cylinder part 54 are positioned so that those center axes may correspond.

  The 1st cylinder part 52 is formed with the flexible material. As a flexible material, when solid particles contained in the slurry are caught between the valve body 61 and the valve seat 51, the valve seat 51 is deformed and the valve body 61 and the valve seat 51 are in close contact with each other. A material having flexibility is selected. As the flexible material, a soft material is selected as compared with a metal such as 25% Cr cast steel or ceramics used as a material of the conventional casing 50. Specifically, a resin is used as the flexible material. If the first cylindrical portion 52 is formed of resin, when solid particles are caught between the valve body 61 and the valve seat 51, the valve seat 51 is deformed and the valve body 61 and the valve seat 51 are in close contact with each other. A degree of flexibility can be given. In particular, it is preferable to use a polyether ether ketone resin or a fluororesin as the flexible material. If the 1st cylinder part 52 is formed with polyetheretherketone resin or a fluororesin, the tolerance with respect to abrasion can be given. Even when a fluid having wear properties such as slurry is handled, the first cylindrical portion 52 is less likely to be worn. Moreover, if a fluororesin is used, it can give corrosion resistance in addition to abrasion resistance.

  In addition, the 2nd cylinder part 53 and the 3rd cylinder part 54 are formed with the metal, ceramics, etc. which are used as a raw material of the conventional casing 50. FIG.

  Circumferential grooves are formed on both end faces of the second cylindrical portion 53, and O-rings 71 and 72 are fitted in the respective grooves. Similarly, circumferential grooves are formed on both end faces of the third cylindrical portion 54, and O-rings 73 and 74 are fitted in the respective grooves. The O-ring 72 is sandwiched between the end surface of the first tube portion 52 and the end surface of the second tube portion 53. The O-ring 73 is sandwiched between the end surface of the first tube portion 52 and the end surface of the third tube portion 54.

  As shown in FIG. 1, the check valve 2 is sandwiched between the pump cover 20 and the suction port member 23. The pump cover 20 is provided with a rod 26, and the tip of the rod 26 is passed through a hole formed in the flange portion of the suction port member 23. The suction port member 23 is fastened to the pump cover 20 by screwing a nut 27 into the tip of the rod 26.

  By fastening the suction port member 23 to the pump cover 20, the check valve 2 sandwiched between them is fastened. More specifically, the first cylinder part 52, the second cylinder part 53, and the third cylinder part 54 constituting the casing 50 of the check valve 2 are applied with a fastening force in the axial direction in a state in which they are connected. Yes. A configuration including the pump cover 20, the suction port member 23, the rod 26, and the nut 27 corresponds to a “fastening member” described in the claims.

  By tightening the nut 27, the O-ring 72 is brought into close contact with the end surface of the first tube portion 52 and the end surface of the second tube portion 53. Thereby, the space between the first tube portion 52 and the second tube portion 53 is sealed in a liquid-tight manner. Similarly, the O-ring 73 is brought into close contact with the end surface of the first tube portion 52 and the end surface of the third tube portion 54, so that the space between the first tube portion 52 and the second tube portion 54 is liquid-tightly sealed. Further, when the O-ring 71 is in close contact with the second cylindrical portion 53 and the pump cover 20, the space between them is liquid-tightly sealed. When the O-ring 74 is in close contact with the third cylindrical portion 54 and the suction port member 23, the space between them is liquid-tightly sealed.

Next, the operation of the check valve 2 will be described.
As shown in FIG. 3, it is assumed that the solid particles P contained in the slurry are caught between the valve body 61 and the valve seat 51. In this case, the contact surface 51a of the valve seat 51 formed of a flexible material is deformed (depressed) by the solid particles P. As a result, the valve body 61 and the valve seat 51 come into close contact with each other, and the check valve 2 is completely closed. As a result, the closing delay of the check valve 2 can be suppressed, the generation of the peak hydraulic pressure in which the hydraulic pressure in the hydraulic chamber 11 of the diaphragm pump 1 becomes abnormally high can be suppressed, and the damage to the diaphragm 30 can be suppressed.

  Since the breakage of the diaphragm 30 can be suppressed, the replacement frequency of the diaphragm 30 can be reduced, so that the maintenance cost of the diaphragm pump 1 can be reduced. Moreover, the stop time of the nickel sulfate manufacturing process in which the diaphragm pump 1 is used can be shortened.

  If the 1st cylinder part 52 is formed with resin, it will become easy to wear compared with the case where it forms with a metal. In particular, when the slurry is handled, the valve seat 51 is easily worn. The worn first tube portion 52 needs to be replaced.

  If the fastening of the fastening member of the casing 50 (the configuration including the pump cover 20, the suction port member 23, the rod 26, and the nut 27) is released, the casing 50 is divided into three members (a first cylindrical portion 52 and a second cylindrical portion 53). , And the third tube portion 54). Therefore, the replacement of the first cylinder part 52 is easy.

Next, examples will be described.
Example 1
The slurry was transferred using the equipment shown in FIG. The solid content concentration of the slurry charged in the autoclave 104 is 200 to 300 g / L, and the flow rate is 50 to 100 L / min. The temperature in the autoclave 104 is 150 to 220 ° C., and the pressure is 1.7 to 2.3 MPa as a gauge pressure.

  As the diaphragm pump 1, a triple diaphragm pump was used. The check valve 2 shown in FIG. 2 was used as the suction-side check valve 2 of each unit pump. During the operation period of about one year, the diaphragm 30 was damaged and replaced nine times.

(Comparative Example 1)
The slurry was transferred under the same conditions as in Example 1. However, the conventional check valve 200 shown in FIG. 5 was used as the suction-side check valve 2. The number of times that the diaphragm 30 was damaged and replaced during the operation period of about one year was 45 times.

  From the above, it was confirmed that the breakage of the diaphragm 30 was suppressed when the check valve 2 shown in FIG. 2 was used.

DESCRIPTION OF SYMBOLS 1 Diaphragm pump 2 Suction side check valve 50 Casing 51 Valve seat 51a Contact surface 52 1st cylinder part 53 2nd cylinder part 54 3rd cylinder part 60 Valve part 61 Valve body 62 Valve rod

Claims (6)

A check valve provided on the suction side of a hydraulic diaphragm pump for transferring slurry,
A valve portion having a valve body;
A cylindrical casing having a valve seat;
A spring that urges the valve portion so that the valve body abuts the valve seat,
The casing is
A first tube portion including the valve seat;
A second cylindrical portion connected to one end of the first cylindrical portion;
A third cylinder connected to the other end of the first cylinder,
A check valve for a diaphragm pump, wherein the first tube portion is formed of a flexible material. The check valve for a diaphragm pump according to claim 1, wherein the flexible material is a resin. 2. The check valve for a diaphragm pump according to claim 1, wherein the flexible material is a polyether ether ketone resin or a fluororesin. The said 1st cylinder part, the said 2nd cylinder part, and the said 3rd cylinder part are fastened by the fastening member which applies a fastening force to an axial direction in the state which connected them. Or the check valve for diaphragm pumps of 3 description. A diaphragm pump comprising the check valve according to claim 1, 2, 3 or 4. The slurry comprises a mixed sulfide comprising nickel and cobalt;
6. The diaphragm pump according to claim 5, wherein a discharge side of the diaphragm pump is connected to an autoclave through a pipe.

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