JP5196324B2 - Plunger pump - Google Patents

Description

  The present invention relates to a plunger pump used for pumping a fluid having a high viscosity such as an ultraviolet curable ink.

  The ink supply pump disclosed in Patent Document 1 aims to provide an ink supply pump that is hard to cure even with a viscous fluid that cures when subjected to a large frictional force. This ink supply pump is an ink supply pump including at least a cylinder and a reciprocating piston that reciprocates in the cylinder, and at least one of the contact angles of the material of the piston and the inner surface in contact with the piston is 100 °. The other is 80 ° or more (see Patent Document 1).

JP 2001-90676 A

  However, the ink supply pump disclosed in Patent Document 1 has an O-ring on the piston. For example, in the reciprocating motion of the piston during ink pressure feeding, the inner surface of the cylinder and the O-ring of the cylinder are rubbed against each other. Since the viscous fluid is hardened by the sliding friction and the reciprocating motion of the piston is hindered, there is a possibility that the ink cannot be pumped and the apparatus may be broken. In addition, the plunger that transmits the power of the reciprocating motion of the piston is provided with an O-ring to prevent leakage of ink to the outside, and this O-ring causes sliding friction between the plunger and the cylinder. There is a problem that the ink described above is cured.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a plunger pump capable of pumping a fluid having high viscosity such as ultraviolet curable ink without being cured by sliding friction.

In order to achieve the above object, a plunger pump according to the present invention includes a suction space in which a suction port opens, a cylinder in which one side communicates with the suction space, and a discharge space in which the discharge port is detachably attached to the cylinder. A discharge block portion having a retainer portion detachably attached to the discharge block portion, a seal housing portion provided inside the retainer portion, a plunger reciprocally inserted into the cylinder, and A piston provided at one end; a first valve mechanism provided at the suction opening that opens when the plunger moves toward the discharge space; and closes when the plunger moves toward the suction space; and the piston And is closed when the plunger moves toward the discharge space, and opens when the plunger moves toward the suction space. In the plunger pump comprising a valve mechanism, at least, the second valve mechanism is constituted by the piston body and the piston valve, a predetermined clearance between the outer peripheral surface and the inner peripheral surface of the cylinder of the piston body And a plurality of grooves on the outer peripheral surface of the piston body .

By providing a predetermined clearance between the piston body and the plunger, the contact area with the inner surface of the cylinder can be reduced, and sliding friction at these parts can be reduced. Can be prevented. Further, by providing a groove on the outer peripheral surface of the piston body, a seal mechanism is formed between the piston body and the plunger, and the sealing performance at the clearance can be ensured .

The seal housing portion is provided with a combination seal including an O-ring portion for performing sealing and a low friction portion with which the plunger abuts, and further, a drain port is provided in the retainer portion .

  By providing the combination seal in the seal housing portion, it is possible to reduce friction with the plunger and to prevent curing of the UV ink. Further, since the drain port is provided in the retainer portion, it is possible to discharge the ink that has flowed in between the combination seal.

A clearance is provided between the seal housing portion and the plunger, and a plurality of grooves are provided on the inner peripheral surface of the seal housing portion.

By providing a clearance between the seal housing portion and the plunger, it is possible to further reduce friction with the plunger. Further, by forming a groove on the inner peripheral surface of the seal housing portion, it is possible to form a seal mechanism with respect to the clearance between the seal housing portion and the plunger, thereby preventing inflow of ink.

The surface of the plunger is preferably subjected to non-adhesive treatment . This makes it possible to prevent ink from adhering to the sliding member surface.

It is desirable to insert a cylindrical member subjected to non-adhesive treatment between the cylinder and the plunger .

  As a result, it is possible to reduce the friction associated with the sliding of the plunger and to prevent ink from adhering. The non-adhesive treatment is a coating with a fluororesin such as polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, and polyvinyl fluoride.

As described above, according to the present invention, by providing a predetermined clearance between the piston body and the plunger, it is possible to reduce contact friction with the cylinder, and by providing a groove on the outer peripheral surface of the piston body, In order to prevent ink from flowing into the clearance by forming a sealing mechanism between the piston body and the plunger, it is possible to pump a highly viscous fluid such as UV curable ink without being cured by friction. It becomes possible to prevent a failure of the apparatus.

  In addition, since a combination seal formed from a low friction member is provided at a portion where the plunger and the seal housing portion come into contact with each other, sliding friction can be further reduced, and ink curing can be prevented.

By providing a clearance between the seal housing part and the plunger, it is possible to further reduce friction with the plunger, and by providing a groove on the inner peripheral surface of the seal housing part, It becomes possible to prevent the inflow of ink by forming a seal mechanism with respect to the clearance between them.

  Further, since the surface of the plunger is subjected to the non-adhesive treatment, it is possible to prevent ink from adhering to the sliding member surface.

  Furthermore, by inserting a cylindrical member with non-adhesive treatment between the cylinder and the plunger, there is no need to perform non-adhesive treatment on the plunger surface. It is possible to reduce friction caused by sliding and to prevent ink adhesion.

It is schematic structure sectional drawing which showed the state when the plunger of the plunger pump which concerns on this invention rose. It is schematic structure sectional drawing which showed the state when the plunger of the plunger pump which concerns on this invention fell. It is the partially expanded sectional view which showed the state between a piston body and a cylinder. It is the partially expanded sectional view which showed the contact state of the combination seal and the plunger. It is the partially expanded sectional view which showed the state between a seal housing part and a plunger. It is the schematic structure sectional view showing the plunger pump which provided the low friction sleeve in the plunger.

  The plunger pump of the present invention will be described below with reference to the drawings. In addition, although demonstrated using an ultraviolet curable ink (UV ink) as an example of a high-viscosity fluid, it is not specifically limited, The high-viscosity fluid sensitive to various shearing forces can be used.

  1 and 2, a plunger pump 1 for pumping UV ink is shown. This plunger pump 1 has one end connected to a power source such as an air cylinder (not shown) by a joint, and the other end provided with a piston 3. The plunger 2 and the retainer portion 8 that slidably holds the plunger 2 are mounted, and a discharge port block portion 9 having a discharge port 91 for supplying ink to a printing machine (not shown), and one end of the discharge port block portion 9 Is fitted, and at least the other end is constituted by a cylinder 4 having a suction port 6 to which a wiper 5 is attached.

  At one end of the cylinder 4, a suction-side pump valve 42 (first valve mechanism) is provided that functions as a check valve that allows only ink to flow into the first pump chamber 41.

  The piston 3 (second valve mechanism) includes a piston body 30 that isolates the first pump chamber 41 and the second pump chamber 43, and a piston valve that adjusts the inflow of ink into the valve passage 33 by opening and closing the valve. 31 and a valve passage 33 which is a passage of ink to the second pump chamber 43.

  A seal housing portion 7 is provided inside the retainer portion 8 so as not to leak UV ink to the outside of the apparatus.

  In the retainer portion 8, a drain port 81 that discharges ink that has entered between the outer diameter of the plunger 2 and the seal housing portion 7 to the outside is located at a position higher than the sliding position of the piston 3 (downstream). Is provided.

  In the plunger pump 1 configured as described above, when the plunger 2 is lifted, that is, when the plunger 2 moves to the discharge port 91 side in FIG. 1, the suction side pump valve 42 is opened and the suction port is connected to the first pump chamber 41. Ink flows from 6. Next, when the plunger 2 descends, that is, when the plunger 2 moves to the suction port 6 side in FIG. 2, the suction side pump valve 42 is closed, while the piston valve 31 is opened, and the first pump chamber 41 is opened. At the same time as the ink flows into the pump chamber 43 through the valve passage 33, the ink is discharged from the discharge port 91. Subsequently, in the ascending process of the plunger 2, the ink that has flowed into the second pump chamber 43 is discharged from the discharge port 91 and at the same time, the ink flows into the first pump chamber 41.

In the operation of the plunger pump 1 as described above, friction is generated by the sliding of the plunger 2 on the outer peripheral surface of the piston body 30 and the inner peripheral surface of the cylinder 4, so that the UV ink is cured and hinders pumping. There is a fear. Therefore, in this embodiment, a predetermined clearance 34 is provided between the piston body 30 and the cylinder 4 for the purpose of reducing the contact area between the piston body 30 and the cylinder 4. is there.

However, when the clearance 34 is provided, the sealing performance between the piston body 30 and the cylinder is deteriorated. Therefore, as shown in FIG. 3, a sealing groove 32 is provided on the outer peripheral surface of the piston body 30. The piston body groove 32 may be formed in a spiral shape like a screw groove, or a plurality of ring-shaped ones may be formed.

As described above, by providing the predetermined clearance 34 between the piston body 30 and the cylinder 4, the contact area with the cylinder 4 can be reduced, and a groove is provided on the outer peripheral surface of the piston body 30. Since a seal is formed between the piston body 30 and the cylinder 4, the inflow of ink in the clearance 34 can be prevented.

  In the conventional O-ring provided in the seal housing portion 7, friction is generated by sliding of the plunger 2, and the inflowed ink may be cured. For this reason, in this embodiment, as shown in FIG. 4, a combination seal 71 is fitted into the seal housing portion 7 as a seal member. The combination seal 71 is composed of an O-ring portion and a low-friction portion that is formed integrally with the O-ring portion and facilitates sliding of the plunger 2. The friction generated by the above is reduced.

  The combination seal 71 is preferably formed of a low friction material or coated with a low friction material. This low friction material is generally so-called Teflon (registered trademark), and is a fluororesin such as polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, and polyvinyl fluoride.

  As described above, by using the combination seal 71, the sliding friction can be further reduced.

  The friction between the plunger 2 and the seal housing portion 7 can be further reduced by reducing the contact area. Moreover, when ink adheres to the plunger 2, it hardens | cures and may obstruct reciprocation. In the present embodiment, a predetermined clearance 74 is provided between the seal housing part 7 and the plunger 2 to reduce the contact area with the plunger 2, and a groove is provided in the inner diameter of the seal housing part 7 to this clearance 74. A seal mechanism is formed, and the plunger 2 is further treated with a non-adhesive material to prevent ink adhesion.

  Thus, as shown in FIG. 5, a predetermined clearance 74 is provided between the plunger 2 and the seal housing portion 7. In order to maintain the sealing performance at this portion, the seal housing portion is provided. 7 is preferably provided with a sealing groove 73. Similar to the groove 32 of the piston body, the groove 73 may be formed in a spiral shape like a screw groove or a plurality of ring-shaped grooves.

  Further, the surface of the plunger 2 is subjected to a non-adhesive treatment so that it can be easily peeled even when ink adheres to the outer diameter surface of the plunger 2. The non-sticking treatment is preferably a fluororesin such as Teflon (registered trademark) as described above.

  As described above, by providing the predetermined clearance 74 between the plunger 2 and the seal housing portion 7, it is possible to reduce the contact area and prevent the ink from curing. In addition, by providing the groove 73 of the seal housing portion 7, it is possible to form a seal mechanism between the plunger 2 and prevent ink from entering. Furthermore, by applying non-adhesive treatment to the plunger 2, it is possible to prevent ink from adhering to the plunger 2, and even when it adheres, it can be easily peeled off.

  In this embodiment, as shown in FIG. 6, a member 72 made of a non-adhesive material, such as a sleeve, is disposed on the outer periphery of the plunger 2 to reduce friction with the seal housing portion 7. is there. Further, the sleeve 72 may be formed from a non-adhesive material, or may be subjected to a non-adhesive treatment on the surface.

  As described above, non-adhesion treatment is performed around the plunger 2 to prevent ink adhesion and sticking at the sliding position of the plunger 2.

1 Plunger pump 2 Plunger 3 Piston 4 Cylinder 5 Wiper 6 Suction port 7 Seal housing portion 8 Retainer portion 9 Discharge port block portion 30 Piston body 31 Piston valve 32 Piston body groove 33 Valve passage 34 Clearance 41 between piston body and cylinder 1 pump chamber 42 suction side pump valve 43 second pump chamber 71 combination seal 72 sleeve 73 groove 74 of seal housing portion 81 clearance between plunger and seal housing 81 drain port 91 discharge port

Claims (3)

A suction space in which the suction port opens, a cylinder in which one communicates with the suction space, a discharge block portion that is detachably attached to the cylinder and has a discharge space in which the discharge port opens, and is detachable from the discharge block portion An attached retainer portion, a seal housing portion provided inside the retainer portion, a plunger reciprocally inserted into the cylinder, a piston provided at one end of the plunger, and the plunger provided at the suction port A first valve mechanism that opens when the plunger moves toward the discharge space, and closes when the plunger moves toward the suction space, and closes when the plunger moves toward the discharge space. And a second valve mechanism that opens when the plunger moves to the suction space side. Te,
The second valve mechanism includes a piston body and a piston valve, and provides a predetermined clearance between the outer peripheral surface of the piston body and the inner peripheral surface of the cylinder, and a plurality of grooves are formed on the outer peripheral surface of the piston body. I arranged things,
A clearance is provided between the seal housing part and the plunger, and a plurality of grooves are provided on the inner peripheral surface of the seal housing part.
The seal housing portion is provided with a combination seal including an O-ring portion for performing sealing and a low friction portion with which the plunger abuts, and
A plunger pump characterized in that a drain port is provided in the retainer portion .   2. The plunger pump according to claim 1, wherein the surface of the plunger is subjected to non-adhesive treatment.   The plunger pump according to claim 1 or 2, wherein a cylindrical member subjected to non-adhesive treatment is attached to the outer periphery of the plunger.

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