DIFFERENTIAL PRESSURE INDICATOR

• US 3,595,200 A
• Filed: 06/03/1968
• Issued: 07/27/1971
• Est. Priority Date: 06/03/1968
• Status: Expired due to Term

• Current Assignee: Parker-Hannifin Corporation
• Original Assignee: Guido D. Cilento
• Inventors: Cilento, Guido D.
• Application Number:
  US04/734,143
• Time in Patent Office: 1,149 Days
• US Class Current: 116/267
• CPC Class Codes: B01D 35/143 Filter condition indicators
• CPC Class Codes: H01H 35/38 actuated by piston and cylinder
• CPC Class Codes: H01H 36/008 Change of magnetic field wherein the magnet and switch are fixed, e.g. by shielding or relative movements of armature for reed switches H01H36/002
• CPC Class Codes: Y10S 116/42 Oil filter

Abstract

A pressure-sensitive indicator comprises a housing having a first means movable towards and away from a first position. A second means, movable towards and away from the first means, is normally retained towards the first means when the first means is in the first position. The first and second means are spaced apart by separating means. The second means is retained away from the first means until the first means is returned to the first position.

Claims

1. A pressure-sensitive device which comprises a housing;

magnetic means fixed within said housing and defining therewith a first chamber and a second chamber;

indicating means located in said first chamber, said indicating means being movable from a first position adjacent said magnetic means to a second position away from said magnetic means;

pressure-sensitive means located in said second chamber, said pressure sensitive means being movable from a first position adjacent said magnetic means to a second position away from said magnetic means;

first biasing means located in said first chamber for maintaining said indicating means its second position;

second biasing means located in said second chamber for maintaining said pressure sensitive means in its first position;

said magnetic means having a variable flux of lines of force such that when said pressure sensitive means is in its first position said indicating means is held by said magnetic means in its first position and when said pressure-sensitive means is in its first position and when said pressure-sensitive means is in its second position said indicating means is held in its second position by said first biasing means.

2. A device according to claim 1 wherein said indicating means is provided with a thermoresponsive member which maintains it in its first position below a predetermined temperature.

3. A device according to claim 1 wherein said pressure-sensitive means is provided with a thermoresponsive member which maintains it in its first position below a predetermined temperature.

4. A device according to claim 1 wherein said pressure-sensitive means is moved to its second position by a predetermined pressure differential.

5. A device according to claim 1 wherein said indicating means is maintained in its second position until reset.