Safe start checking liquid processing system

• US 4,084,547 A
• Filed: 03/24/1976
• Issued: 04/18/1978
• Est. Priority Date: 03/24/1976
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Deziel, Frederick T.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US05/669,777
• Time in Patent Office: 755 Days
• Field of Search: 236/21 R, 137/392, 122/504, 73/304 R, 219/333 X, 340/244 C
• US Class Current: 122/504
• CPC Class Codes: G01F 23/243 Schematic arrangements of probes combined with measuring circuits
• CPC Class Codes: G01F 23/36 using electrically actuated indicating means G01F23/38 takes precedence

Abstract

A self checking system is disclosed in various forms, and is specifically shown as applied to a system which checks the level of water in a boiler before an associated fuel burner system is initiated. Before the liquid or water in the system can be processed, the liquid level is either caused to be depressed or is simulated as depressed, and this depression in the liquid level is sensed and the level verified before a circuit is completed in the liquid processing system.

Claims

1. A liquid processing system which verifies the proper condition of the system prior to the initiation of the processing of a liquid, including:

liquid level sensing means having at least two contact means;

a first of said contact means being open circuited upon the indication of said liquid being at a level at which said processing is desired to be initiated and close circuited upon an indication of said liquid being below said level;

a second of said contact means being close circuited with said liquid indicated as at said level and open circuited with said liquid indicated as below said level;

switching means energized by said first contact means being close circuited to indicate said liquid is below said level;

said switching means latching itself into said energized state upon once being energized; and

said switching means further including control circuit means in electrical series with said second contact means to complete an energizing circuit to initiate the processing of the liquid upon said liquid being at said level after the operation of said switching means.

2. A liquid processing system as described in claim 1 wherein said switching means includes a relay having a normally open contact which closes upon operation of said relay to latch said relay into an energized state;

and said control circuit means being a second normally open contact controlled by said relay.

3. A liquid processing system as described in claim 2 wherein said liquid level sensing means includes a liquid level sensor system having a second relay which operates said two contact means;

one of said contact means being a normally open contact of said second relay; and

the other of said contact means being a normally closed contact of said second relay.

4. A liquid processing system as described in claim 3 wherein said liquid processing system is adapted to include liquid reservoir means connected to said liquid processing system and wherein said reservoir means has a small volume compared to said system;

said reservoir means including electrically operated drain means to lower the level of the liquid in said reservoir means while having a minimal effect upon the liquid level in said liquid processing system;

said liquid level sensing means being responsive to the liquid level of said reservoir means; and

said first relay having a normally closed contact connected to said electrically operated drain means to deenergize said drain means upon said first relay becoming energized to thereby close said drain means.

5. A liquid processing system as described in claim 4 wherein said liquid processing system is a boiler and a fuel burner system with said liquid being water;

and said contacts of said relays being adapted to complete an energizing circuit for said fuel burner system upon said water level being verified by said liquid level sensing means being cycled each time said boiler fuel burner system is initiated.

6. A liquid processing system as described in claim 5 wherein said liquid level sensing means includes a water sensing probe system to control said second relay.

7. A liquid processing system as described in claim 2 wherein said liquid processing system is adapted to include level reservoir means connected to said liquid processing system and wherein said reservoir means has a small volume compared to said system;

said reservoir means including electrically operated drain means to lower the level of the liquid in said reservoir means while having a minimal effect upon the liquid level in said liquid processing system;

said liquid level sensing means including a float responsive to the liquid level of said reservoir means to operate said two contact means; and

said relay means having a normally closed contact connected to said electrically operated drain means to deenergize said drain means upon said relay becoming energized to thereby close said drain means.

8. A liquid processing system as described in claim 7 wherein said liquid processing system is a boiler and a fuel burner system with said liquid being water;

said two contact means of said liquid level sensing means completing an energizing circuit for said fuel burner system upon said water level being verified by said level sensing means being cycled each time said boiler fuel burner system is initiated.

9. A liquid processing system as described in claim 2 wherein said liquid level sensing means includes amplifier means having input connection means connected to sensing element means;

said amplifier means further connected to control said two contact means; and

said input connection means including a third normally open contact which is operated by said relay;

said third normally open contact causing said liquid level sensing means to respond as if said sensing element means failed to sense a liquid in said liquid processing system.

10. A liquid processing system as described in claim 9 wherein said sensing element means includes an inherently safe liquid sensor that responds to the absence of liquid or a short circuited sensing element as if no liquid is present.

11. A liquid processing system as described in claim 10 wherein said amplifier means includes a relay to operate said two contact means.

12. A liquid processing system as described in claim 11 wherein said liquid is water and said processing system includes a boiler;

and said relays are adapted to energize a fuel burner system in response to the presence of water being verified by said level sensing means being cycled each time said fuel burner system is initiated.