JP2003227460A - Piston pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piston pump which sucks and discharges a fixed quantity of fluid, and switches a channel without a complicated structure. <P>SOLUTION: In the piston pump where a piston 12 housed inside of a tubular cylinder 11 with a bottom is reciprocated and the fluid is sucked and discharged from a port communicated with a pressurizing/depressurizing chamber in the depth of the cylinder, the cylinder 11 houses the piston 12 rotatably and has a suction port 14 and a discharge port 15a-15e in its peripheral wall. The piston 12 has a connection groove 16 communicated with the pressurizing/depressurizing chamber 13 and selectively communicated with the suction port 14 or the discharge port 15 by the rotation of the piston, and only the selected port is connected to the pressurizing/depressurizing chamber 13 via the connection grove 16. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston pump capable of reciprocating a piston housed in a cylinder to suck and discharge a fixed amount of fluid and switch a flow path.

[0002]

2. Description of the Related Art A piston pump is a metering pump for metering a fluid such as a paint or a sample in a device such as an automatic color matching machine or a chromatography, and is connected to a switching valve which is communicably connected to a plurality of flow paths. Used. According to this structure, when a certain amount of fluid is sucked from one liquid tank and is discharged (supplied) to another flow path, as shown in FIG. The flow path 2 and the piston pump 3 are connected to pull the piston 4, and the pressurizing / depressurizing chamber 5
By depressurizing the inside, the liquid is sucked into the cylinder,
The liquid is contained in the cylinder, the switching valve 6 is switched to connect the discharge passage 7 and the piston pump 3, and the piston 4 is pushed there to pressurize the inside of the pressurizing / depressurizing chamber 5 so that the liquid is contained in the cylinder. A fixed amount of liquid can be supplied to another discharge passage.

[0003]

However, in the prior art as described above, the piston pump and the switching valve (flow path switching mechanism) exist separately, and the conventional switching valve has a complicated structure depending on the type. Is expensive, or requires a large amount of external force to operate,
As described above, the device having the structure including the piston pump and the switching valve has a problem that the control is complicated and the entire device is very expensive.

In view of such a state of the art, it is an object of the present invention to provide a piston pump capable of sucking and discharging a fixed amount of fluid and switching a flow path without having a complicated structure.

[0005]

The features of the present invention for solving the above-mentioned conventional problems and achieving the intended purpose are as follows.
In a piston pump that reciprocates a piston housed in a cylindrical cylinder with a bottom and sucks and discharges a fluid from a port communicating with a pressurizing / depressurizing chamber at the inner part of the cylinder, the cylinder allows the piston to rotate freely. A connection for accommodating and having a suction port and a discharge port on the circumferential wall of the cylinder, wherein the piston communicates with the pressurizing / depressurizing chamber, and is selectively communicated with the suction port or the discharge port by rotating the piston. A groove is provided, and only the selected port is communicated with the pressurizing / depressurizing chamber via the connecting groove.

It is preferable that a plurality of suction ports and / or discharge ports are provided, and that the suction ports and the discharge ports are radially arranged, and that the suction ports and the discharge ports are spirally arranged, It is preferable to include rotation control means for controlling the rotation angle and slide control means for controlling the stroke amount of the piston.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a piston pump according to the present invention will be described with reference to FIGS. The same parts as those of the conventional example described above will be designated by the same reference numerals.

FIG. 1 shows the outline of a piston pump according to the present invention. Reference numeral 10 in the drawing is a piston pump.

The piston pump 10 comprises a cylinder 11 having a bottomed cylindrical shape, and a piston 12 housed inside the cylinder 11 so as to be slidable (reciprocating and rotating) in the axial direction and the circumferential direction, respectively. A pressurizing / depressurizing chamber 13 is formed inside the cylinder by being surrounded by the inner wall of the cylinder 11 and the piston 12.

As shown in FIG. 3, the cylinder 11 has a suction port 14 communicating with the pressurizing / depressurizing chamber 13 on the peripheral wall portion.
, And a plurality of discharge ports 15, 15, ..., The suction port 14 and the discharge ports 15, 15, ... Are arranged radially, that is, on one circumference of the outer peripheral surface of the cylinder.

As shown in FIG. 4, the piston 12 is formed in a columnar shape, and a connecting groove 16 is formed on the outer circumference thereof. A piston rod 17 is non-rotatably connected to the piston 12 at the front end. A rotation control means 18 and a reciprocating operation control means 19 are connected to the piston 12 via a piston rod 17.

The connecting groove 16 is formed on the outer circumference along the axial direction, and its length is the position where the piston 12 is pushed deeply, that is, the volume in the pressurizing / depressurizing chamber 13 is zero. However, the length is such that it can communicate with the ports 14 and 15, and its width is approximately the same as the outer diameter of the port opening.

The rotation control means 18 comprises a stepping motor 20 whose rotary shaft 20a is directly connected to the piston rod 17, which gives rotation to the piston rod 17, and a CPU (not shown) which controls the rotation of the stepping motor 20. ing. Then, the stepping motor 20 is
The piston rod is rotated by a predetermined angle in response to a command signal from the CPU.

The reciprocating motion control means 19 is adapted to vertically move the lift table 19a to which the stepping motor 20 is fixed by a desired stroke of the piston 12, and the lift table 19a and the lift table 19a. It is composed of a screw shaft 19c into which a female screw member 19b fixed to is screwed, and a stepping motor 19d for controlling the rotation of the screw shaft 19c via a belt transmission mechanism.

By using the piston pump configured as described above, in the case of sucking a fixed amount of liquid from one liquid tank and supplying it to another flow path, the following procedure is suitable. It can be carried out.

First, as shown in FIG. 5 (A), when the piston 12 is pushed inward, that is, when the volume inside the pressurizing / depressurizing chamber 13 is zero, the piston 12 is rotated by the rotation control means 18 and connected. The groove 16 is selectively communicated with the suction port 14. At this time, the suction port 14 communicates with the inside of the pressurizing / depressurizing chamber 13 via the connection groove 16, while the discharge port 15a ...
15e is closed by the outer peripheral surface of the piston 12, and only the suction port 14 communicates with the pressurizing / depressurizing chamber.

In this state, the reciprocating motion control means 19 is operated to pull the piston 12 forward by a predetermined stroke amount to depressurize the pressurizing / depressurizing chamber 13, and a predetermined amount of liquid is sucked from the suction port 14 into the cylinder (pressurizing). It is sucked into the decompression chamber) (FIG. 5 (B)).

Next, while the liquid is contained in the cylinder 11, the rotation control means 18 is operated to rotate the piston 12 to a position where the connection groove 16 communicates with a desired discharge port (15a in the figure) ( FIG. 5 (C)), the pressurizing / depressurizing chamber 13
The inside is communicated with the desired discharge port 15a. At this time,
Other than the desired discharge port 15a, that is, the suction port 14 and the discharge ports 15b to 15e are closed by the outer peripheral surface of the piston.

In this state, the reciprocating motion control means 19 pushes the piston 12 inward to pressurize the inside of the pressurizing / depressurizing chamber 13 to discharge (supply) the liquid to the flow path communicating with the discharge port 15a (see FIG. D)).

In this way, the liquid sucked from the suction port 14 is supplied to another flow path.

Further, by appropriately selecting the discharge ports 15a to 15e according to the situation, the discharge ports 15a to 1 can be selected.
The liquid can be supplied to the flow path communicating with 5e.

As shown in FIG. 6, the ports 22 and 22 are
You may make it arrange | position spirally. Port 22,
By arranging 22 ... in a spiral shape, considering the minimum required wall thickness between adjacent ports and the outer diameter of the pipe or the like connected to the ports, it is preferable to arrange them on the circumference (radially). Also, it is possible to shorten the circumferential distance between the adjacent ports 22 and 22. That is, the rotation angle of the piston 12 required to switch the communication state with the connection groove 16 from the desired port to the adjacent port can be reduced, and more ports can be provided than when the ports are arranged on the circumference. Can be formed. At this time, the length of the connection groove 16 formed in the piston is formed such that even if the piston has a position where the volume of the pressurizing / depressurizing chamber is zero, it can communicate with the port at the farthest position from the back side. The stroke amount of
It is the distance from the back side to the closest port.

In the above embodiment, an example in which a plurality of discharge ports are provided for one intake port has been described, but a plurality of intake ports may be provided, and the discharge port is limited to one place. May be.

Further, in the above-described embodiment, the example mainly applied to the liquid has been described, but the present invention can also be applied to the gas.

[0025]

As described above, the piston pump according to the present invention reciprocates the piston housed in the cylindrical cylinder having a bottom, and sucks the fluid from the port communicating with the pressurizing / depressurizing chamber at the inner part of the cylinder. In the piston pump for performing discharge, the cylinder is rotatably accommodated and the cylinder peripheral wall is provided with a suction port and a discharge port, and the piston communicates with the pressurizing / depressurizing chamber, By providing a connection groove that is selectively communicated with the suction port or the discharge port by rotating, only the selected port is communicated with the pressurizing / depressurizing chamber via the connection groove. Controlling because the device can be simplified by combining the role of a metering pump with the role of a switching valve without using a switching valve. Easy, the cheaper the entire apparatus.

Further, since a plurality of suction ports and / or discharge ports are provided and the suction ports and discharge ports are radially arranged, the fluid can be distributed and supplied to a plurality of flow paths by appropriately selecting a desired port. can do.

By arranging the suction port and the discharge port in a spiral shape, the circumferential distance between adjacent ports is shortened, and it is necessary to switch the communication state with the connection groove from one port to the next port. Since the rotation angle of the piston can be reduced, it is possible to provide a larger number of ports than those arranged side by side (radially) on the circumference.

Since the rotation control means for controlling the rotation angle of the piston and the slide control means for controlling the stroke amount of the piston are provided, it is possible to suitably switch a plurality of flow paths, and at the same time, to determine a fixed amount. The fluid can be suitably sucked and discharged.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an embodiment of a piston pump according to the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

3 (A) is a vertical sectional view showing the cylinder in FIG.
(B) is the same BB sectional drawing.

FIG. 4 (A) is a front view showing the piston of the above, (B)
Is a bottom view of the same.

5A to 5D are cross-sectional views showing a rotational operation state of a piston.

FIG. 6 is a front view showing another embodiment of the piston pump according to the present invention.

FIG. 7 is a block diagram schematically showing a liquid distribution device using a conventional piston pump.

[Explanation of symbols]

10 piston pump 11 cylinders 12 pistons 13 pressurization chamber 14 Suction port 15 Discharge port 16 connection groove 17 Piston rod 18 Rotation control means 19 Reciprocating motion control means 19a lift 19b Female screw member 19c screw shaft 19d stepping motor 20 motor 20a rotating shaft

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3H045 AA03 AA09 AA12 AA22 AA37                       BA19 BA28 CA06 DA05 DA15                       DA21 EA14 EA44                 3H070 AA07 BB04 BB07 CC12 DD08                       DD24 DD72                 3H075 AA01 BB03 BB13 CC11 CC35                       DA03 DA04 DB03 DB33 EE02                       EE04 EE12 EE17 EE18

Claims (4)

[Claims] 1. A piston pump for reciprocating a piston housed in a cylindrical cylinder having a bottom to suck and discharge a fluid from a port communicating with a pressurizing / depressurizing chamber in the inner part of the cylinder, wherein the cylinder is A piston is rotatably accommodated and a cylinder peripheral wall is provided with a suction port and a discharge port. The piston communicates with the pressurizing / depressurizing chamber, and the piston is rotated to selectively connect with the suction port or the discharge port. A piston pump comprising a connection groove communicating with the pressurizing / depressurizing chamber via the connection groove. 2. The piston pump according to claim 1, further comprising a plurality of suction ports and / or discharge ports, wherein the suction ports and the discharge ports are radially arranged. 3. The piston pump according to claim 1, wherein the suction port and the discharge port are spirally arranged. 4. The piston pump according to claim 1, comprising rotation control means for controlling a rotation angle of the piston, and slide control means for controlling a stroke amount of the piston.