JPS6332946Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a micro liquid pump used for chemical liquid pumps or kerosene supply pumps for petroleum fan heaters of household heaters.

Conventional configuration and its problems Pumps using piezoelectric elements have a small displacement of the piezoelectric element, so the volume change per pump is small.If compressible gas is mixed into the pump chamber, the volume change is converted into It has the problem that it is absorbed by gas and the pump stops working.

In FIG. 1, a piezoelectric element 2 having a circular cross section is attached to a pump body 1 while being sealed;
A pump chamber 3 in a closed space is formed. The pump chamber 3 is initially filled with a nearly incompressible liquid. A suction check valve 4 and a discharge check valve 5 are coupled to the pump chamber 3.
In response to a change in the volume of the pump chamber 3, the liquid is sent from the suction check valve 4 to the discharge check valve 5. The piezoelectric element 2 vibrates in the thickness direction when an alternating current voltage is supplied from a power source (not shown). Due to this vibration change, the volume of the pump chamber 3 is alternately contracted and expanded. When gas is sucked in through the suction check valve 4, air bubbles 6 rise in the pump chamber 3 toward the discharge check valve 5. This is because the discharge check valve 5 is positioned higher than the suction check valve 4 with respect to gravity. However, in order to obtain a desired pump flow rate, the pump chamber 3 has a volume of a certain value or more, so there is a distance of a certain value or more between the suction check valve 4 and the discharge check valve 5. Therefore, the number of bubbles 6 is equal to the rising speed of the bubbles and the vibration frequency of the piezoelectric element 2 in the pump chamber 3, and as a result, the total volume of the bubbles 6 increases the vibration of the piezoelectric element 2. Volume changes are absorbed by compressibility, which prevents pumping action.

Purpose of the invention The purpose of the invention is to provide a pump configuration in which compressible gas hardly remains in the pump chamber.

Structure of the invention This invention has an operating chamber separate from the pump chamber, and the suction and discharge check valves are opened in this operating chamber.With this structure, the buoyancy caused by the difference in specific gravity between gas and liquid is utilized. By providing a discharge check valve in the working chamber above the suction check valve, gas can be quickly removed.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows the configuration of an embodiment of the present invention, and components having the same numbers as those in FIG. 1 have similar configurations and functions. A working chamber 7 is provided above the pump chamber 3 in terms of gravity and communicates with the pump chamber 3.
The suction check valve 4 exists within the suction member 8, and the suction member 8 is fixed and fluidly sealed from the outside by the pump body 1 and the sealing material 9. Suction check valve 4
The pump-side opening 10 opens into the working chamber 7 and is provided sufficiently close to the inlet 11 of the discharge check valve 5.

When the piezoelectric element 2 is operated in this state, the change in volume of the pump chamber 3 is directly connected to the working chamber 7 by the liquid, so air bubbles entering from the opening 10 immediately enter the inlet 11 and stay in the working chamber 7. This does not prevent the pump action from harming the pump as in the past.
Furthermore, even if a leak occurs in the suction check valve 4 and the discharge check valve 5, all the liquid in the pump chamber 3 will escape in FIG. 1 and the pump will no longer function, but in FIG.
If the design is done well, the gas volume can be made small so as not to interfere with the pump action.

Effects of the invention According to the invention, by providing a working chamber that is gravitationally above the pump chamber and bringing the opening of the suction check valve close to the discharge check valve, air bubbles do not accumulate in the pump chamber. , without air bubbles impairing the pumping action.
This ensures stable pump action.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a conventional pump using a piezoelectric element, and FIG. 2 is a side sectional view of a micro liquid pump according to the present invention. 1...Pump body, 2...Piezoelectric element, 3...Pump chamber, 4...Suction check valve, 5...Discharge check valve,
7... Working chamber.

Claims (1)

[Scope of utility model registration request] A pump chamber whose volume changes using a piezoelectric element,
It has a working chamber that communicates with the pump chamber, and a suction check valve and a discharge check valve that are opened in the working chamber, and the pump chamber is connected to the working chamber, and the suction check valve is connected to the discharge check valve in the direction of gravity. A micro-liquid pump that is located at a higher position than the pump chamber and the working chamber is filled with incompressible liquid.