Diaphragm pump

Abstract

A diaphragm pump comprising a pressure chamber arranged such that the volume of the pressure chamber is expanded and contracted by oscillation of a diaphragm (5), a suction-side check valve (7) for sucking air into the pressure chamber and a discharge-side check valve (8) for discharging air from the pressure chamber. The suction-side check valve is arranged to close by a valve body (17) being elastically deformed and brought into close contact with a valve seat, and open by the valve body elastically returning to the normal shape and coming out of contact with the valve seat. The discharge-side check valve is arranged to open by a valve body (18) being elastically deformed and producing a space relative to a valve seat, and close by the valve body elastically returning to the normal shape and coming into close contact with the valve seat.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates to a diaphragm pump having a pressure chamber arranged such that the volume of the pressure chamber is expanded and contracted by oscillation of a diaphragm. [0003] 2. Description of the Related Art [0004] A diaphragm pump comprises, as a wall of a pressure chamber, a diaphragm which is driven, for example, by an electromagnet to oscillate so that the oscillation of the diaphragm expands and contracts the volume of the pressure chamber alternately. The diaphragm pump sucks a fluid (air, for example) into the pressure chamber through a suction-side check valve when the volume of the pressure chamber is expanded, and pressurizes and discharges the air from the pressure chamber through a discharge-side check valve when the volume of the pressure chamber is contracted. [0005] Generally, when the discharge pressure of the diaphragm pump is raised, the discharge quantity thereof tends to decrease. W...

AI Technical Summary

Benefits of technology

[0008] The primary object of this invention is to provide a diaphragm pump that can remove operational instability at high operating pressures, without requiring a complicated structure.

[0014] In the diaphragm pump having the above structure, the suction-side check valve is arranged to have a space between the valve body and the valve seat, and hence functions as a normally-open check valve. By using this suction-side check valve in combination with the discharge-side check valve which functions as a normally-closed check valve, the time for which the suction-side check valve is open in the process of expanding the volume of the pressure chamber for sucking air from the suction port into the pressure chamber can be made longer, so that a load on the diaphragm can be reduced.

[0015] Since the load on the diaphragm is reduced, it is not necessary to apply part of the pressure in the pressure chamber to the diaphragm as a back pressure as in the conventional case, and hence, a complicated structure is not required. Further, even when the diaphragm pump is operated at a high operating pressure, the diaphragm can be caused to oscillate with certainty, since the load on the diaphragm is reduced as mentioned above. Thus, also when the diaphragm pump is operated at a high operating pressure, stable operational characteristics can be guaranteed.

[0016] Also in the alternate diaphragm pump having paired pressure chambers arranged such that their volumes are expanded and contracted in a complementary manner, it can be ensured that a sufficient amount of air is sucked into the paired pressure chambers, alternately. Consequently, mutual interference of the paired pressure chambers, or in other words, unstable operation of one pressure chamber affecting the operation of the other pressure chamber can be prevented. Thus, the operational balance between the paired pressure chambers can be prevented from becoming unstable, and the pressure difference liable to be produced between the paired pressure chambers can be removed. Since it can be ensured that a stable amount of air is sucked into the paired pressure chambers even when the diaphragm pump is operated at a high operating pressure, the discharge pressure of the diaphragm pump can be easily kept constant and the above-mentioned instability phenomenon can be prevented effectively.

Problems solved by technology

When the operating pressure of the diaphragm pump is raised to obtain a high discharge pressure, however, a high pressure in the pressure chamber makes it difficult for the diaphragm to oscillate.

This easily causes variation in the time for which the suction-side check valve is open, and thereby makes the amount of a fluid sucked into the pressure chamber unstable.

The adoption of such arrangement, however, causes a problem that the casing (sealed space) containing the electromagnet requires a complicated structure.

For an alternate diaphragm pump which has diaphragms provided at the opposite ends of a rod-like shaft driven by an electromagnet to move back and forth so that the volumes of paired pressure chambers are expanded and contracted in a complementary manner by means of the diaphragms, a particularly complicated structure is required, since a device for preventing the paired pumping chambers from becoming connected through the casing (sealed space) containing the electromagnet is required.

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