Double diaphragm pressure switch for a well water system

• US 4,867,645 A
• Filed: 09/12/1988
• Issued: 09/19/1989
• Est. Priority Date: 09/12/1988
• Status: Expired due to Fees

• Current Assignee: Bailey G. Foster
• Original Assignee: Bailey G. Foster
• Inventors: Foster, Bailey G.
• Primary Examiner(s): Croyle, Carlton R.
• Assistant Examiner(s): SCHEUERMANN, DAVID W
• Application Number:
  US07/242,490
• Time in Patent Office: 372 Days
• Field of Search: 417/38, 200/83 J, 200/83 Y
• US Class Current: 417/38
• CPC Class Codes: E03B 5/045 with surface tanks
• CPC Class Codes: F04B 47/00 Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps by using positive or negative pressurised fluid medium acting directly on the liquid to be pumped F04F1/00

Abstract

A switch mechanism for controlling a motor that runs a well pump. Water line pressure acts on a diaphragm to pressurize an air chamber that communicates with a pressure switch. The switch components are isolated from the water line (by the air chamber), to minimize the possiblity of switch failure due to ice formation (winter time operations) or corrosion.

Claims

1. In association with an outdoor water well that comprises a motor-driven pump, a water output line leading from the pump, and a pressure tank connected to the output line to maintain a minimum water pressure therein:

the improvement comprising means for operating the pump motor whenever the water level in the tank falls below a predetermined level;

said operating means comprising a first upright housing connected at its lower end to the water line;

a movable partition within the housing subdividing said housing into a lower water chamber communicating with the water line and an upper air chamber; and

a motor-control pressure switch communicating with the air chamber, whereby air trapped in the air chamber exerts an operating force on the pressure switch;

said housing comprising two axially-aligned upper and lower cup-shaped housing sections having mouth surfaces facing one another;

said movable partition comprising a first flexible diaphragm having a peripheral flange clamped between the mouth surfaces of the upper and lower housing sections;

said housing sections being essentially the same size so that the diaphragm flange is at approximately the housing mid plane;

said first diaphragm having a hat-shaped cross section depending into the lower housing section when the upper air chamber is depressurized;

the water line pressure exerting a force on the diaphragm lower face such that high water line pressures cause said first diaphragm to be deflected upwardly into a hat-shaped cross-section extending upwardly into the upper housing section;

said first diaphragm being sized to extend substantially the full axial depth of each housing section in the fully deflected positions of the diaphragm;

said pressure switch comprising a second housing structure (42) located directly above said first housing, and a second deflectable diaphragm (43) mounted in said second housing structure so that the lower face of said second diaphragm is in open communication with the air chamber defined by the upper surface of the first diaphragm;

the stroke distance for the first diaphragm being many times the stroke distance of the second diaphragm, whereby significant air pressure changes take place as the first diaphragm moves between its two positions extending, respectively, into the lower and upper housing sections.