JPS58204985A - Fixed displacement pump for small amount - Google Patents

Abstract

PURPOSE:To enable a very small amount of a liquid to be fed with no pulsation without a check valve being arranged, by operating three piston pumps with cams shifted by 120deg. from each other and made in synchronism with a cam shaft which is rotatably driven by a motor. CONSTITUTION:Piston 3a through 3c are made contact, under pressing force by springs 4a through 4c, with cams 5a through 5c which are shifted by 120deg. from each other and are secured onto a cam shaft 6 rotatary driven by a motor 7. Accordingly, liquid may be sequentially fed from piston pumps P1 through P3 every one-third of rotation, thereby the liquid may be fed with no pulsation even without a check valve being arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a micro-quantity metering pump, and more particularly to a micro-quantity metering pump that uses a piston pump and has a structure suitable for delivering liquid without pulsation.

Conventional piston-type micrometer metering pumps have a structure in which check valves are provided on the suction side and the discharge side to send liquid. The check valve used was one in which the ball was held down by a spring, or the valve was closed by the ball's own weight.

In order to send a very small amount of liquid within μt using a metering pump with the above structure, it is necessary to make the structure of the check valve small.In order to make the valve small, the balls, springs, etc. must be made small. This makes production difficult. Further, there are disadvantages in that foreign matter tends to adhere to the valve portion and the spring is easily corroded. Therefore, there was an inconvenience in that it required periodic disassembly and maintenance.

The present invention has been made based on the above-mentioned findings, and its purpose is to provide a piston-type micro-metering pump that can pump a small amount of liquid without pulsation without providing a check valve. .

The feature of the present invention is that six piston pumps are arranged at equal intervals, and each piston pump is fixed to a camshaft rotated by a motor, shifted by 1208 degrees, and operates in synchronization with each cam. There is a configuration and a point IC.

The present invention will be described below with reference to the embodiments shown in FIGS. 1 and 4 and the embodiments shown in FIG.
This will be explained in detail with reference to FIGS. 6 and 5.

Recitation 1 Diagram 1 A new view of the operation of a metering pump according to a civil engineering invention. In FIG. 1, 1 is a pump housing, and a piston 5a of a six-piston pump is connected to the housing 1 via an O-ring 2.

6b and 6a are installed. The pistons 6a to 6c are in contact with the cams 5a to 5c by the pressing force of the springs 4a and -4c, respectively. 6 is designed to be rotated by a motor. 8 is a suction port, and 9k is a discharge port.

Figure 2 is an explanatory diagram of the liquid feeding process of the pump in Figure 1, (■),
Three steps (2) and (2) are shown. In step (I), the pump P1 is in a liquid feeding state, the pump P2 is in a closed state, and the pump P6 is in a suction state. Process (in ID, ・1111
1"I Pump P1 is closed, pump P2 is in suction state, pump P3 is in liquid feeding state, and on the process side, pump P1 is in suction state, pump P
2 is for liquid feeding, and pump I''!A is in a closed state.

Strokes 10a to 1 of the six pumps P1 to P6 (
]c and the rotation angle of the cams 5a to 5c are shown in FIG. In this way, each piston pump P1 every 1/3 rotation.
~P3 allows the liquid to be fed sequentially, and the liquid can be fed without pulsation without providing a check valve.

FIG. 4 is an explanatory diagram showing another embodiment of the present invention. Fourth
In the figure, d: A pump 11 consisting of piston pumps P1 to P3 and a piston pump P4 are placed on the outer periphery of the cams 5a to 5C.
~ Pump 12 consisting of P6 and piston pumps P7 to P9
Pumps 13 consisting of the following are provided at 120° intervals, and the suction ports and discharge ports of each pump 11 to 13 are connected to each other.

The wcs diagram is a diagram schematically showing the state, where 14 is a suction port and 15 is a discharge port. In this case, cams 5a to 5
By rotating C in the direction of the arrow shown in the figure, liquid feeding becomes more continuous every 173 rotations.

As explained above, according to the present invention, there is an effect that a small amount of liquid can be fed without pulsation without providing a check valve.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view for explaining the operation of an embodiment of the micrometer metering pump of the present invention, Fig. 2 is an explanatory diagram of the liquid feeding process of the pump shown in Fig. 1, and Fig. 3 shows the three pumps shown in Fig. 1. 4 is an explanatory diagram showing another embodiment of the present invention, and FIG. 5 is a diagram showing the relationship between the stroke of the pump and the rotation angle of the cam. FIG.
FIG. 2 is an explanatory diagram of a connected state of a suction port and a discharge port of each pump. 1...Housing, 3a-6C...-Piston, 4.
...Spring, 5a-5C...Cam, 6-...Camshaft, 7...Motor, )j...Suction port, 9...
・Discharge port. %1 "Applicant's name hb Tatsukoki Co., Ltd. Sai1 Figure 72 Figure 741 No. 51

Claims (1)

[Claims] t. A configuration in which six piston pumps are arranged at equal intervals, and each piston pump operates in synchronization with a respective cam that is fixed to a camshaft rotationally driven by a motor, shifted by 120 degrees. A micro-quantity metering pump characterized by the following. Z. The micro-quantity metering pump according to claim 1, wherein six sets of three sets of the six piston pumps are provided at 120° intervals around the outer periphery of the cam.