DIAPHRAGM PUMP WITH DUAL SPRING OVERFILL LIMITER

摘要

A diaphragm pump includes a housing having a pumping chamber containing fluid. The pump has a transfer chamber containing hydraulic fluid, and a hydraulic fluid reservoir in fluid communication with the transfer chamber. The pump housing forms a cylinder with a piston defining a piston inner chamber and sliding in the cylinder. A valve leads to the piston inner chamber with a valve spool slidably mounted in the piston inner chamber to cover the valve and uncover the valve. A diaphragm connects to the valve spool by a plunger. An overfill limiter includes a spacer slidably mounted in the piston inner chamber. A first spring is intermediate the valve spool and the spacer and a second spring is intermediate the end of the piston inner chamber and the spacer, the second spring having a second spring constant greater than the spring constant of the first spring.

主权项

1. A diaphragm pump comprising:
a housing having a pumping chamber containing fluid to be pumped; a transfer chamber adapted to contain hydraulic fluid, and a hydraulic fluid reservoir in fluid communication with the transfer chamber; a cylinder; a piston sliding in a reciprocating motion in the cylinder, the piston defining a piston inner chamber, the piston inner chamber having an end; a valve leading to the piston inner chamber; a valve spool slidably mounted in the piston inner chamber, the valve spool covering the valve in a first position and uncovering the valve in a second position; a spacer slidably mounted in the piston inner chamber intermediate the valve spool and the end of the piston inner chamber; a diaphragm connected to the valve spool by a plunger and supported by the housing, the diaphragm defining a pumping chamber side and a transfer chamber side, the pumping chamber side at least partially defining the pumping chamber and the transfer chamber side at least partially defining the transfer chamber; a first spring in the piston inner chamber intermediate the valve spool and the spacer, the first spring having a first spring constant; a second spring in the piston chamber intermediate the end of the piston inner chamber and the spacer, the second spring having a second spring constant greater than the first spring constant.