ELECTRONIC CONTROL MEANS FOR DISPENSING APPARATUS

• US 3,680,070 A
• Filed: 05/25/1970
• Issued: 07/25/1972
• Est. Priority Date: 05/25/1970
• Status: Expired due to Term

• Current Assignee: Marcus I. Nystuen
• Original Assignee: Marcus I. Nystuen
• Inventors: Nystuen, Marcus I.
• Primary Examiner(s): Habecker, Thomas B.
• Application Number:
  US05/040,206
• Time in Patent Office: 792 Days
• Field of Search: 340/236,244 137/88,93 307/318,252N,252B 328/165 315/351,352,354
• US Class Current: 222/14
• CPC Class Codes: A47L 15/0055 Metering or indication of used products, e.g. type or quantity of detergent, rinse aid or salt; for measuring or controlling the product concentration
• CPC Class Codes: A47L 15/241 the dishes moving in a horizontal plane
• CPC Class Codes: A47L 15/4418 in the form of liquids A47L15/4409, A47L15/4436, A47L15/4445 take precedence
• CPC Class Codes: A47L 15/449 Metering controlling devices A47L15/4229 takes precedence
• CPC Class Codes: G05D 21/02 characterised by the use of electric means
• CPC Class Codes: Y10T 137/034 Controlled by conductivity of mixture
• CPC Class Codes: Y10T 137/2499 Mixture condition maintaining or sensing
• CPC Class Codes: Y10T 137/2509 By optical or chemical property

Abstract

An electrical bridge circuit having a conductivity cell in one leg thereof, normally biased away from the null point so that a signal is produced by the bridge when the conductivity cell is operating at a desired set point. A semiconductor switching circuit is attached to a solenoid valve to vary material added to a solution, such as soap mixed with water. A combination of switching circuit bias, the signal from the bridge and a signal platform produced by a zener diode during portions of the positive cycle of an alternating power source, normally maintain the switch in a non-conducting state but sufficient variation of the conductivity cell in a direction caused by low conductivity, or too little material in the solution, produces a sufficient signal to switch the semiconductor switch into a conducting state to operate the solenoid valve.

Claims

1. Electronic control means comprising:

a. switching means switchable between a first state and a second state upon the application thereto of a signal having a predetermined voltage;

b. biasing means for providing a clipped alternating signal having a voltage level during the clipped portion thereof greater than the predetermined signal voltage required to cause said switching means to change states;

c. condition responsive bridge means for sensing variations in a predetermined condition about a normal value and providing an alternating output signal varying about an off-null set point in response to variations in the predetermined condition, the output signal being in a direction and normally of sufficient magnitude to overcome the signal produced by said biasing means;

d. summing means connecting the condition responsive means and the biasing means to said switching means for summing the output signal and the clipped alternating voltage signal to cause said switching means to change states whenever the sum thereof exceeds the predetermined signal voltage.

2. Electronic control means as set forth in claim 1 wherein the condition responsive means includes a conductivity sensor connected in one leg of an electrical bridge circuit.

3. Electronic control means as set forth in claim 2 wherein the bridge circuit has a null point and is biased so as to operate in a substantially unbalanced condition entirely on one side of said null point.

4. Electronic control means as set forth in claim 1 wherein the biasing means includes a zener diode electrically connected to a source of alternating electrical power for clipping the alternating signal provided by the power source to provide said clipped biasing signal.

5. Electronic control means as set forth in claim 1 wherein the switching means includes a semi-conductor device electrically connected to a source of alternating electrical power.

6. Electronic control means as set forth in claim 1 having in addition electrical storage means connected to the switching means for delaying the switching thereof from the first state to the second state until the signal applied thereto has a pre-determined duration as well as the predetermined level.

7. Electronic control means as set forth in claim 1 having in addition electrical storage means connected to the switching means for maintaining the switching means in the second state a predetermined time after the switching thereof and the removal of the signal producing the switching.

8. Electronic control means as set forth in claim 7 having in addition alarm circuitry means electrically connected to the switching means and including a timing circuit for triggering an alarm indication upon the switching means remaining in the second state at least a predetermined time.

9. Electronic control means as set forth in claim 1 having in addition solenoid controlled valve means electrically connected to the switchiNg means for controlling the flow of a material in a conduit of dispensing apparatus.