JP2021195935A - High viscosity fluid pump - Google Patents

Abstract

To avoid hardening of a UV ink etc. in a slide portion of a pump of a high viscous fluid, in particular, the UV ink etc.SOLUTION: A plunger 40 is connected to an upper reciprocating drive part 20, and a piston valve 62 into which a piston 66 is fitted is connected to the plunger 40. A foot valve part 80 is provided below the piston valve 62 and a fluid suction port 100 is provided below the foot valve part 80. A diaphragm 44, partially folded and fixed at both end parts, is provided at a gap 43 formed between the plunger 40 and a ground retainer 42 which covers the plunger 40 when the fluid is supplied from a fluid discharge port 110 to the outside by vertical movement of the piston 66 and the piston valve 62. A partially spherical part 66S is provided at the piston 66, and an inner peripheral surface of a suction tube 68 located at the outer side of the partially spherical part 66S is slid thereon. A circular ball receiving base 84 is provided at a lower part of a foot valve housing 82 of the foot valve part 80 to sandwich a ball 86.SELECTED DRAWING: Figure 1

Description

The present invention relates to an improvement of a sliding portion of a pump such as a high-viscosity fluid, particularly UV ink, and particularly to a pump capable of avoiding curing such as UV ink.

Patent Document 1 is a high-viscosity pump, in which the pump body is composed of an upper body, a suction tube, a valve housing, and a chute, and a high-viscosity material suction port is provided in the lower portion thereof. A high-viscosity material discharge port is opened on the side surface of the upper body. A plunger is fitted to the upper body so as to be vertically movable via a seal member, and the upper end of the plunger is attached to a drive shaft of a reciprocating drive unit.

A packing and a throat bearing as a sealing member fitted to the plunger are held in the upper body by a gland retainer screwed into the upper body. Further, the upper part of the rod is screwed into the lower part of the plunger, and a piston sliding in the suction tube is fitted to the outer peripheral portion of the rod via an annular gap, and the upper end of the annular gap has a through hole. After that, it is communicated in the suction tube.

By the axial movement of the plunger, the rod and the piston, the lower end opening of the annular gap is opened and closed by the seat portion formed on the rod. The rod is connected to the excavator rod, and a excavator plate for scraping high-viscosity material is provided at the lower part of the excavator rod.

When the plunger rises, the lower end opening of the annular gap is locked and closed by the seat portion of the rod, and the piston rises, and the high-viscosity material on the upper side of this piston is discharged from the high-viscosity material discharge port, and at the same time, the excavator plate. The high-viscosity material scraped up by the high-viscosity material suction port is sucked up.

Further, when the plunger is lowered, the seat portion is separated from the lower end opening of the annular gap, so that the high-viscosity material in the lower space of the piston descending together with the plunger enters the upper space of the piston through the annular gap and the through hole. Moving.
In this high-viscosity pump, the packing as a sealing member wipes off the high-viscosity material attached to the peripheral surface of the plunger when the plunger rises, so as to minimize leakage of the high-viscosity material carried out by the plunger. However, this packing cannot completely remove the high-viscosity material strongly attached to the peripheral surface of the plunger, and the high-viscosity material leaks to the outside through the gap between the plunger 17 and the gland retainer 33. was there.

The present invention solves the problem that the high-viscosity material attached to the peripheral surface of the plunger and leaking from the pump body is automatically returned from the sealed body to the high-viscosity material suction port via the circulation passage and leaks to the outside.

Patent Document 2 reliably prevents leakage of the fluid inside the pump without providing a complicated sealing structure, and can be used for an internal fluid having a higher discharge pressure than a reciprocating pump equipped with a normal bellows seal. It was used as a pump to handle fluids containing harmful substances and flammable substances. A piston ring or packing is provided on the piston, an auxiliary seal is provided on the piston shaft, and a shaft seal is provided on the piston shaft on the atmosphere side of the auxiliary seal to seal the cylinder chamber side from the atmosphere side with a flexible member. be.

In Patent Document 3, the main body of the ink pump device has a cylinder cylinder having an ink intake port and an ink ejection port, a reciprocating moving body reciprocating in the cylinder cylinder, and an ink attached to the tip of the reciprocating moving body. It is composed of a disk-shaped pumping board to be pumped.

A trip rod is connected to the operating rod that operates this piston, and on the other end side of the trip rod, there is a switching claw body that engages with the switching slider block and reciprocates this switching slider block based on the reciprocating movement of the trip rod. It is provided.
This switching claw body is for switching the supply of the driving fluid in which hydraulic oil or the like is used.

Patent Document 4 is a plunger pump used for pumping a highly viscous fluid such as an ultraviolet curable ink, and provides a predetermined clearance between the piston body and the cylinder to reduce the contact area with the cylinder. Further, by providing a groove on the outer peripheral surface of the piston body 30, a seal is formed between the piston body and the cylinder, so that the inflow of ink can be prevented.
A clearance was provided between the seal housing portion and the plunger, and a plurality of grooves were provided on the inner peripheral surface of the seal housing portion.
The seal housing portion is provided with a combination seal including an O-ring portion for sealing and a low friction portion with which the plunger abuts, and the gland retainer portion is provided with a drain port.

In all of the above known documents, sealing is performed using a sealing member. However, in such a sealing structure, the high-viscosity fluid causes the members of the sealing portion to slide with each other. There is a problem that the high-viscosity fluid sticks and the operating efficiency of the sliding portion is lowered.

Japanese Unexamined Patent Publication No. 3-246380 Japanese Unexamined Patent Publication No. 2006-144741 Japanese Patent Application Laid-Open No. 2003-286968 Japanese Patent No. 5196324

An object of the present invention is to eliminate sliding as much as possible in the seal portion of a high-viscosity fluid pump and to provide a non-contact sliding seal structure.

Conventionally, it is a fluid handled by a high-viscosity fluid pump, and in particular, the characteristic of ultraviolet curable ink (UV ink) is that it may be cured by ultraviolet rays, and the cured ink is sent to the printing machine, which causes printing problems. It leads to. When a pump for oil-based ink is used, since sliding packing is used, UV ink sticks to the sliding packing, etc., which causes resistance and causes a failure that the pump does not operate. was there.

To solve the above problem, avoiding the sliding packing when using the oil-based ink pump can avoid the curing of the ink, so the sliding packing is not used in the gap with the gland retainer that covers the plunger. A diaphragm sealing structure was provided to prevent ink sticking.

In the sliding part between the piston and the suction tube, packing is not used, and a partial spherical part is provided for the shape of the outer diameter part of the piston to narrow the area of the sliding part, or between the piston and the inner diameter of the suction tube. A clearance was provided to create a seal structure in which the metals slide in a non-contact manner.

The foot valve has a valve opening / closing structure that allows the ball to float and sink, eliminating the sliding part.

According to the invention according to claim 1 to 7, the present invention has a plunger connected to an upper reciprocating drive portion, a piston valve fitted with a piston connected to the plunger, and a foot valve portion below the plunger valve. In a high-viscosity fluid pump in which a fluid suction port is provided further below the piston and a fluid suction port is provided to supply fluid from the fluid discharge port to the outside by vertical movement of the piston and the piston valve, the gland retainer covering the plunger is provided. There is no sliding part between the plunger and the gland retainer because a diaphragm made of a flexible material that can be partially folded back and fixed at both ends is provided in the gap between the two to form a sealing member for a high-viscosity fluid.

In the inventions of claims 8 to 11 of the present invention, an ejector is provided in the gap between the ground retainer and the ground retainer covering the plunger in the above invention, and the diaphragm is moved to the outer surface of the plunger by the negative pressure sent from the ejector. And improved the degree of adhesion on the inner surface of the ground retainer.

According to claims 12 to 16 of the present invention, a plunger is connected to an upper reciprocating drive unit, a piston valve fitted with a piston is connected to the plunger, and a foot valve portion is provided below the piston valve. In a high-viscosity fluid pump in which a fluid suction port is provided below and the fluid is fed to the outside from the fluid discharge port by the vertical movement of the piston and the piston valve, the piston is fitted to the suction tube and is partially attached to the piston. A spherical portion is provided to slide the inner peripheral surface of the suction tube, or the piston is provided with a clearance between the partially spherical portion and the inner peripheral surface of the suction tube to form a non-contact sliding seal structure.

According to claims 17 and 18 of the present invention, a plunger is connected to an upper reciprocating drive unit, a piston valve fitted with a piston is connected to the plunger, and a foot valve portion is provided below the plunger valve. In a high-viscosity fluid pump in which a fluid suction port is provided below and the fluid is supplied to the outside from the fluid discharge port by the vertical movement of the piston and the piston valve, the foot valve portion is a circular ball receiver at the bottom of the foot valve housing. A table was provided to hold the ball.

According to the inventions of claims 1 to 7, in a high-viscosity fluid pump, a diaphragm that is partially foldable and fixed at both ends is provided in a gap between the ground retainer and the plunger that covers the plunger, and the high-viscosity fluid, particularly UV, is provided. Since it is an ink sealing member, there is no sliding part between the plunger and the gland retainer, and it is possible to prevent the high-viscosity fluid from sticking.

In the inventions of claims 8 to 11, an ejector is provided in the gap between the plunger and the gland retainer, and the diaphragm is subjected to the negative pressure sent from the ejector to maintain the degree of adhesion between the outer surface of the plunger and the inner surface of the gland retainer. Since it was raised, the high-viscosity fluid, especially UV ink, entered the gap between the body of the folded diaphragm and the inverted U-shaped space formed in the body, and sliding did not occur between the diaphragms, so that the high-viscosity fluid Sticking can also be prevented.

In the inventions of claims 12 to 16, the piston is fitted to the suction tube, and the piston is provided with a partially spherical portion to slide on the inner peripheral surface of the suction tube, so that the sliding portion is limited. Adhesion of high-viscosity fluid is limited. Alternatively, since the piston is provided with a clearance between the partially spherical portion and the inner peripheral surface of the suction tube to form a non-contact sliding seal structure, it is possible to prevent the high-viscosity fluid from sticking.

In the inventions of claims 17 and 18, the foot valve portion is provided with a circular ball pedestal at the lower portion of the foot valve housing, and the ball pedestal is hollowed out in a circular shape on the inside and has a tapered portion on the upper portion. Since the structure is such that the ball is sandwiched at the lower end of the taper, the valve opening / closing structure is based on the floating and sinking of the ball.

It is a front view of the UV ink pump 10 which is a high viscosity fluid of this invention. It is a left side view of the part of the upper reciprocating drive part 20 of FIG. It is a schematic diagram showing the inside of the plunger 40 or less of the UV ink pump 10 which is a high-viscosity fluid of FIG. (A) is a schematic view showing a state at the bottom dead center of the UV ink pump 10 which is a high-viscosity fluid of FIG. 3, and (B) is an enlarged view of a ball cradle 84. It is a schematic diagram showing the state of the top dead center of the UV ink pump 10 which is a high-viscosity fluid of FIG. It is a front view showing an example of the diaphragm of this invention. The shape of the diaphragm of FIG. 6 is shown, (A) is a schematic view showing the state of top dead center, (C) is a schematic diagram showing the state of bottom dead center, and (B) is surrounded by a circle of (A). The enlarged view of the part (D) is an enlarged view of the part surrounded by the circle of the same (C). (A) is a perspective view showing the shape of the piston of the present invention, and (B) is an upward perspective view showing the state from above of (A). It is a schematic diagram showing the piston and the diaphragm of this invention.

The high-viscosity fluid pump 10 (particularly a UV ink pump) of the present invention includes an upper reciprocating drive unit 20, a plunger 40, a piston valve unit 60, a foot valve unit 80, a fluid suction port 100, and a fluid discharge port 110.

(Upper reciprocating drive unit 20)
As shown in FIG. 1, in the upper reciprocating drive unit 20, the air motor 22 is located at the uppermost portion, and the cylinder 32 and the drive shaft 24 connected downward are driven up and down. Further, the silencer 26 connects the upper portion of the air motor 22 and the lower portion of the air motor 22 with a tube 28 to mute the exhaust sound of the air exhausted from the air motor 22. Reference numeral 30 is an air inlet. The cylinder 32 and the ejector 34 are connected by a tube 36, and the pressurized air supplied from the air inlet 30 generates a negative pressure by the action of the ejector 34. The ejector 34 communicates with the gap 43 between the plunger 40 and the ground retainer 42, which will be described later.

(Plunger and grand retainer)
As shown in FIG. 2, the upper end of the plunger 40 is vertically and vertically connected to the drive shaft 24. The plunger 40 is composed of an upper major axis portion 40L and a lower diameter portion 40S thereof, and the outside of the major axis portion 40L of the plunger 40 is covered with a ground retainer 42 as shown in FIG. There is a gap 43 between the plunger 40 and the gland retainer 42, and the diaphragm 44 is fitted as a sealing member described later from the major diameter portion 40L of the plunger to the minor diameter portion 40S. In order to prevent damage to the diaphragm 44 during disassembly and assembly of the high-viscosity fluid pump 10, a bracket 48 is provided so that both the plunger 40 and the gland retainer 42 can be fixed.

(Piston valve)
A coupling rod 62R extending from the upper end portion 62H of the piston valve 62 of the piston valve portion 60 is fitted to the lower portion of the short diameter portion 40S of the plunger 40. As a result, the plunger 40 and the piston valve 62 reciprocate up and down in conjunction with each other.

A pumping board 62L is provided at the lower end of the piston valve 62, and the pumping board 62L has a trumpet shape in which the central outer diameter of the piston valve 62 expands toward the end, and the lower end has a disk shape. .. A split pin 64 is ringed and fixed around the piston valve 62 at a portion where the coupling rod 62R at the upper end of the piston valve 62 is fitted to the lower portion of the short diameter portion 40S of the plunger 40. .. A piston valve columnar portion 62C is formed between the upper end portion of the piston valve 62 and the lower pumping board body 62L.

(Piston and piston valve)
The piston 66 is fitted in the piston valve 62, the piston 66 is in a free state from the piston valve 62, and the piston valve columnar portion 62C penetrates through the through hole 66P at the upper part of the piston 66. ..

As shown in FIGS. 8 and 9, the piston 66 has a hollow shape and is composed of an upper gantry handle portion 66G and a lower partial spherical handle portion 66S. The lower portion is a columnar ring-shaped portion 66R, and the partially spherical portion 66S is connected to the ring-shaped portion 66R.

The piston 66 is fitted in the suction tube 68 and reciprocates up and down. The suction tube 68 is joined to the gland retainer 42 via an upwardly squeezed truncated cone tube 70.

The piston 66 has a structure in which the upper portion of the pumping board 62L and the lower end portion of the partially spherical portion 66S are in contact with each other when the piston valve 62 rises.

(Foot valve part 80)
The foot valve portion 80 is covered with the foot valve housing 82, and the lower end portion of the suction tube 68 is fitted and connected to the upper end portion of the foot valve housing 82. The lower part of the foot valve housing 82 is provided with a ball pedestal 84, and the ball pedestal 84 is hollowed out in a circular shape on the inside and has a tapered portion 84T on the upper part. It has a structure to be sandwiched (see FIG. 4 (B)). Above the ball, a stopper 88 is provided at the lower end of the suction tube 68 (see FIG. 3), and serves as a stopper for the floating ball due to the inflow of fluid from the lower part.

The lower part of the foot valve portion 80 is a plate 90, and the plate 90 is provided with a fluid suction port 100 in the center.

(Fluid discharge port)
The truncated cone tube 70 above the suction tube 68 is provided with a fluid discharge port 110 on the side surface, and a portion facing the fluid discharge port 110 is a discharge port 112 used for cleaning the fluid or the like.

(Bottom dead center of high-viscosity fluid pump)
The operation of the high-viscosity fluid pump 10 of the present invention will be described. FIG. 4 shows a state in which the drive shaft 24, the plunger 40, and the piston valve 62 are lowered from the air motor 22, and the state of the bottom dead center is shown. The lower end of the short diameter portion 40S of the plunger 40 is in contact with the upper end portion of the portal-shaped handle portion 66G of the piston 66, and is in a state of being lowered from above the suction tube 68. The partially spherical portion 66S of the piston 66 is hollow, the pumping board 62L of the piston valve 62 is further lowered, and there is a gap between the piston 66 and the piston valve 62. If a gap is created between the piston 66 and the piston valve 62 while the piston valve 62 is descending from above, the fluid is pushed upward like the flow of L1 and is pushed upward from the fluid discharge port 110. It is ready to be supplied to the outside. As the pumping board 62L of the piston valve 62 descends, the distance between the pumping board 62L and the ball is shortened, so that the ball 86 is pushed in the direction of the ball cradle 84 and the fluid from the fluid suction port 100 is used. Is in a state where it cannot flow backwards.

(Top dead center of high-viscosity fluid pump)
FIG. 5 shows a state in which the drive shaft 24, the plunger 40 and the piston valve 62 are raised from the air motor 22, and the state of the top dead center is shown.

When the piston valve 62 rises from the bottom dead center, the contact state between the lower end of the short diameter portion 40S of the plunger 40 and the upper end portion of the portal-shaped handle portion 66G of the piston 66 is eliminated, and the piston valve 62 As the pumping board 62L rises, it comes into contact with the lower end of the partially spherical portion 66S of the piston 66. After that, as the pumping board 62L of the piston valve 62 rises, the partially spherical portion 66S of the piston 66 is also pushed from below and rises. During this period, the gap between the pumping board 62L of the piston valve 62 and the partially spherical portion 66S of the piston 66 disappears, so that the fluid does not enter from below the pumping board 62L of the piston valve 62, but the piston 66. The upper fluid rises, is pushed upward like the fluid flow L2, and is supplied to the outside from the fluid discharge port 110.

As the pumping board 62L of the piston valve 62 rises, the ball 86 rises and comes into contact with the stopper 88 as the distance between the pumping board 62L and the ball increases. A space is created between the ball cradle 84 and the ball 86, and the fluid from the fluid suction port 100 flows in like the flow of L3, and new fluid flows into the space where the pumping board 62L has risen. Become.

(Characteristics of high-viscosity fluids, especially UV inks)
The high-viscosity fluid to which the present invention is applied, particularly UV ink, is an ink that is cured by ultraviolet rays. When pressure is applied or (iii) UV ink comes into contact with aluminum or zinc, it may trigger curing (gelling), and the cured ink is sent to the printing machine for printing. May lead to problems with the ink.

In particular, when an oil-based ink pump is used to transport UV ink, the oil-based ink pump usually uses a sliding packing, but with UV ink, the ink itself sticks to the sliding packing or the like. , There was a symptom that this sticking became resistance and the pump did not work.

(Diaphragm)
In particular, UV ink enters up to the part of the gap 43 between the plunger 40 and the gland retainer 42, but the seal structure of this part is such that when a sliding packing is used, the ink sticks and the pump operates. It may have an adverse effect.

Therefore, in the present invention, the diaphragm 44 is adopted as the sealing member. According to FIG. 6, the diaphragm 44 uses a material in which the outer cover is rubber and the base cloth is polyester fiber, which is a flexible material. As shown in FIG. 6, the shape of the diaphragm 44 is a cylindrical shape as a whole, with a buttock-shaped body 44B in the center, a raised portion 44P protruding in the width direction on the upper end side, and a bottom portion 44L on the lower end side. , The bottom portion is hollow, and is composed of the hollow portion 44H. The diaphragm 44 itself may be made of a stretchable material and may be in close contact with the portion to which the plunger 40 is mounted.

When assembling the plunger 40, the diaphragm 44 is fixed by sandwiching the raised portion 44P with the lower end portion 42P of the ground retainer 42. The body portion 44B is fitted from the major axis portion 40L of the plunger 40 to the flange surface 40F, and the bottom portion 44L is fitted and fixed to the bottom portion 40LB of the major axis portion 40L of the plunger 40. As for the bottom portion 44L, as shown in FIG. 7B, the key-shaped retainer 50 holds the bottom portion 44L of the diaphragm 44 and is tightened and fixed by the nut 52.

Since the diaphragm 44 is made of a flexible material, the outer cover is made of rubber, and the base cloth is made of polyester fiber, the diaphragm 44 is closely attached to the outside of the plunger 40. The material of the diaphragm may be any material as long as it is flexible, and rubber alone may be used. When the outer cover is made of rubber and the base cloth is made of another material, the material is not particularly limited, such as aramid fiber, polyphenylene sulfide resin (PPS), nylon, glass fiber, and cotton.

The diaphragm 44 is located at the bottom of the body 44B and in the gap 43 between the plunger 40 and the gland retainer 42 when the high viscosity fluid pump 10 reaches the top dead point, either vertically or in the vertical direction of the pump. It is folded back in an inverted U shape (44U). A fluid, particularly UV ink, enters the folded interior to form a sealing structure (see FIG. 7 (A)).

Further, as described above, in order to prevent damage to the diaphragm 44 during disassembly and assembly of the high-viscosity fluid pump 10, a bracket 48 is provided so that both the plunger 40 and the gland retainer 42 can be fixed.

As shown in FIG. 7C, at the bottom dead point of the high-viscosity fluid pump 10, the portion of the diaphragm 44 in the vicinity of the raised portion 44P of the body portion 44B, at the lower part of the gap 43 between the plunger 40 and the gland retainer 42. It is folded back in a U shape in the vertical direction or in the vertical movement direction of the pump (44U). The inside of the folded back is a gap 44S, and a fluid, particularly UV ink, enters the gap 44S to form a sealing structure (see FIGS. 7C and 7D).

In this way, the diaphragm 44 serves as a seal for the gap 43 between the plunger 40 and the gland retainer 42, and the high-viscosity fluid, particularly UV ink, is in the vertical direction of the diaphragm 44 or in the vertical movement direction of the pump. Since the diaphragm 44 itself does not come into direct contact with each other and has no sliding portion because it enters the inner gap 44S folded back in a U shape, the UV ink does not stick to this portion.

(Example of modification of diaphragm)
The method of mounting the diaphragm 44 on the plunger 40 and the ground retainer 42 is not limited to the above mounting method. The raised portion 44P of the diaphragm 44 may not have a particularly raised shape, but may be fixed by a retainer or a nut as in the method of fixing the bottom portion 44L of the diaphragm 44 described above. On the contrary, the bottom portion 44L of the diaphragm 44 described above may have a shape similar to that of the raised portion 44P, and the major diameter portion 40L and the minor diameter portion 40S of the plunger 40 may be divided and fixed by sandwiching them between them. If the structure is cylindrical as a whole when attached to the plunger 40 and the gland retainer 42 and has a butt-shaped body 44B in the center, the gap between the plunger 40 and the gland retainer 42 described above. If it can be used by folding it back in an inverted U shape in the vertical direction or the vertical movement direction of the pump at 43, it can be sufficiently used as a sealing structure.

(Diaphragm and ejector)
Since the diaphragm 44 is used in the folded shape as described above, if the shape cannot be maintained, the diaphragm 44 itself comes into contact with the sliding portion, so that the UV ink, which is a high-viscosity fluid, can be used. It sometimes caused solidification. Therefore, the ejector 34 makes it possible to make the gap 43 between the plunger 40 and the ground retainer 42 negative pressure. As a result, in the non-contact portion of the diaphragm 44 with the UV ink which is a high-viscosity fluid, and in the contact portion between the outside of the plunger 40 and the inside of the gland retainer 42, the air layer is eliminated, so that the plunger 40 is removed. The outside and the inside of the diaphragm 44 are adhered to each other, and the inside of the gland retainer 42 and the diaphragm 44 are adhered to each other to prevent the diaphragm 44 from falling off. Since the UV ink, which is a high-viscosity fluid, enters the sluice, the above-mentioned direct sliding state is eliminated, and the phenomenon that the UV ink, which is a high-viscosity fluid, touches the sliding portion and solidifies is eliminated. With such a configuration, the conventional sliding portion is eliminated, so that the UV ink, which is a high-viscosity fluid, solidifies and adheres to the pump, and the state in which the pump does not move up and down smoothly is solved.

(Partial spherical part of the piston)
As shown in FIGS. 8 and 9, the partial spherical portion 66S at the lower part of the piston 66 is a part of the sphere, and in this portion, even if the piston is tilted from the vertical line, the suction tube 68 of the piston 66 is formed. The outer diameters of the contacting parts are the same. Therefore, the structure is such that a slight inclination does not matter. In this way, the piston 66 is fitted in the suction tube 68 and reciprocates up and down. The piston 66 can also reduce the area of the sliding portion of the suction tube 68, so that there is an effect that material sticking due to sliding is less likely to occur.

Here, if the sliding portion of the piston 66 and the suction tube 68 is a conventional one, they are in contact with each other on a surface, and the sliding surface is also large. In that sense, when the partially spherical portion 66S of the present invention is used, there is an advantage in that the sliding portion is in contact close to a line and the sliding portion is narrowed. This is because if the sliding area is reduced, the amount of contact with the UV ink, which is a high-viscosity fluid, is reduced, and the ink can be prevented from being cured.

If a clearance is provided between the partially spherical portion 66S of the piston 66 and the inner diameter of the suction tube 68, the above-mentioned sliding portion is eliminated, and the partially spherical portion 66S and the suction tube 68 do not come into direct contact with each other. It becomes a seal structure of.

The clearance between the outer surface of the partially spherical portion 66S and the inner surface of the suction tube 68 is preferably 0.1 mm to 0.2 mm. The outer surface of the partially spherical portion 66S and the inner surface of the suction tube 68 have a structure in which UV ink, which is a high-viscosity fluid, enters and plays a role in sealing. Since UV ink has a viscosity several times higher than that of oil-based ink, internal leakage is small if the clearance is appropriate, and there is no significant adverse effect on pump performance.

The partially spherical portion of the piston is preferably a part of a circular sphere, but the same effect can be expected with an ellipsoidal sphere. Further, if the spherical portion has, for example, a thin disk shape, it has the effect of reducing the sliding area. Further, it is possible to substitute a truncated cone-shaped one with an upward-facing cone and a downward-pointing truncated cone, even if the pointed portion of the central portion is circular.

The above configuration is an invention for narrowing the sliding portion or eliminating the sliding portion. However, even for such a sliding portion, the surface treatment of the parts of the sliding portion can be applied to the sliding portion. The slidability can be improved. For example, by applying a fluorine-based surface treatment to the outer peripheral portion of the piston 66 and the inner peripheral portion of the suction tube to make a sliding surface having high lubricity, the frictional portion is reduced and the risk of ink sticking is reduced.

(Metal material of wetted parts)
For the metal material of the wetted part, use steel (electroless nickel plating) or stainless steel, and do not use the material (aluminum alloy, electrozinc plating, etc.) that triggers the above ink to cure (gelle). Can prevent curing of UV ink, which is a high-viscosity fluid. The wetted parts include the outer peripheral surface of the plunger 40, the outer peripheral surface of the piston 66, the inner peripheral surface of the suction tube 68, the inner peripheral surface of the foot valve housing 82, the outer peripheral surface of the ball cradle 84, the outer surface of the ball 86, and the like. Can be mentioned.

(Foot valve)
In the foot valve of the present invention, the ball pedestal 84 is provided in the lower part of the foot valve housing 82, the inside of the ball pedestal 84 is hollowed out in a circular shape, and the upper part is a tapered portion 84T, and the tapered lower end 84L. Since it has a structure that sandwiches the ball 86, it has a valve opening / closing structure by the ups and downs of the ball, so there is no sliding part compared to the conventional cylindrical trapezoidal shape, so there is no problem of sticking UV ink. ..

In the above-described embodiment, a non-contact sliding sealing structure is proposed for a sealing method for packing or the like used in a high-viscosity fluid pump, and a sealing method for a high-viscosity fluid pump, which has been difficult in the past, is epoch-making. It is an improvement.

Although the invention is a seal structure used for a high-viscosity fluid pump, particularly a UV ink pump, it can be widely applied to a high-viscosity fluid.

10 High-viscosity fluid UV ink pump 20 Upper reciprocating drive 22 Air motor 24 Drive shaft 32 Cylinder 34 Ejector 40 Plunger 42 Grand retainer 43 Gap 44 Diaphragm 48 Bracket 50 Key retainer 52 Nut 60 Piston valve 62 Piston valve 62L Pumping board 66 Piston 66S Partial spherical part 66G Gate-shaped handle part 68 Suction tube 80 Foot valve part 82 Foot valve housing 84 Ball cradle 84T Tapered part 84L Tapered lower end 86 Ball 90 Plate 100 Fluid suction port 110 Fluid discharge port L1, L2, L3 flow

Claims (18)

A plunger is connected to the upper reciprocating drive part, a piston valve fitted with a piston is connected to the plunger, a foot valve part is provided below the plunger, and a fluid suction port is provided further below the piston and the piston. In a high-viscosity fluid pump that feeds fluid to the outside from a fluid discharge port by moving the valve up and down, a flexible material can be partially folded back in the gap between the gland retainer that covers the plunger and both ends. A high-viscosity fluid pump characterized by being provided with a fixed diaphragm to serve as a sealing member for high-viscosity fluids. The diaphragm, which is partially folded back in the gap with the gland retainer that covers the plunger, is folded back in an inverted U shape in the vertical direction or in the vertical movement direction of the pump, and the inside of the inverted U-shaped portion. The high-viscosity fluid pump according to claim 1, wherein a high-viscosity fluid is allowed to enter the pump, and there is no sliding portion between the plunger and the gland retainer. The high-viscosity fluid pump according to claim 2, wherein the diaphragm has a cylindrical shape and a tail bud shape. The high-viscosity fluid pump according to claim 3, wherein the diaphragm includes a raised portion, a body portion, and a bottom portion. The high-viscosity fluid pump according to claim 4, wherein the raised portion of the diaphragm is fixed to the gland retainer side, and the bottom portion of the diaphragm is fixed to the bottom portion of the major axis portion of the plunger. The high-viscosity fluid pump according to claim 5, wherein when the bottom of the diaphragm is fixed to the bottom of the long diameter portion of the plunger, the bottom of the diaphragm is held by a key-shaped retainer and fastened with a nut. The high-viscosity fluid pump according to claim 6, wherein the high-viscosity fluid of the high-viscosity fluid pump is UV ink. A claim characterized in that an ejector is provided in a gap with a gland retainer covering the plunger, and the diaphragm enhances the degree of adhesion between the outer surface of the plunger and the inner surface of the gland retainer due to the negative pressure sent from the ejector. Item 1 high-viscosity fluid pump. The high-viscosity fluid pump according to claim 8, wherein the raised portion of the diaphragm is fixed to the gland retainer side, and the bottom portion of the diaphragm is fixed to the bottom portion of the major axis portion of the plunger. The high-viscosity fluid pump according to claim 9, wherein when the bottom of the diaphragm is fixed to the bottom of the long diameter portion of the plunger, the bottom of the diaphragm is held by a key-shaped retainer and fastened and fixed with a nut. The high-viscosity fluid pump according to claim 10, wherein the high-viscosity fluid of the high-viscosity fluid pump is UV ink. A plunger is connected to the upper reciprocating drive part, a piston valve fitted with a piston is connected to the plunger, a foot valve part is provided below the plunger, and a fluid suction port is provided further below the piston and the piston. In a high-viscosity fluid pump that feeds fluid to the outside from a fluid discharge port by moving the valve up and down, the piston is fitted in a suction tube, and a partially spherical portion is provided in the piston to form an inner peripheral surface of the suction tube. A high-viscosity fluid pump characterized by being slid. The high-viscosity fluid pump according to claim 12, wherein the partially spherical portion of the piston is a part of a sphere. The high-viscosity fluid pump according to claim 13, wherein a clearance is provided between the outer surface of the partially spherical portion and the inner surface of the suction tube. The high-viscosity fluid pump according to claim 14, wherein the clearance is 0.1 mm to 0.2 mm. The height according to claim 15, wherein UV ink, which is a high-viscosity fluid, is allowed to penetrate into the clearance, and the piston has a seal structure in which the partially spherical portion and the inner peripheral surface of the suction tube are non-contact sliding. Viscosity fluid pump. A plunger is connected to the upper reciprocating drive part, a piston valve fitted with a piston is connected to the plunger, a foot valve part is provided below the plunger, and a fluid suction port is provided further below the piston and the piston. In a high-viscosity fluid pump that feeds fluid to the outside from a fluid discharge port by moving the valve up and down, the foot valve part has a structure in which a circular ball cradle is provided at the bottom of the foot valve housing to hold the ball. A high-viscosity fluid pump characterized by a valve opening / closing structure based on the ups and downs of the piston. The high-viscosity fluid pump according to claim 17, wherein the upper portion of the circular ball cradle has a tapered portion, and the ball can be sandwiched at the lower end of the taper.

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