Dark-initiated liquid flow control circuit for scrub sink

• US 6,279,179 B1
• Filed: 08/10/1999
• Issued: 08/28/2001
• Est. Priority Date: 08/10/1999
• Status: Expired due to Fees

• Current Assignee: William J. Register
• Original Assignee: William J. Register
• Inventors: Register, William J.
• Primary Examiner(s): Recla, Henry J.
• Assistant Examiner(s): NGUYEN, TUAN N
• Application Number:
  US09/371,721
• Time in Patent Office: 749 Days
• Field of Search: 462/3, 440/6, 430/2, 430/4, 430/5, 431/3, 4DI/G 3, 250/206, 250/214.R, 250/214.1, 250/214.A, 250/221, 250/222.1, 340/565, 340/555, 340/573.1, 251/129.04
• US Class Current: 4/623
• CPC Class Codes: E03C 1/05 Arrangements of devices on wash-basins, baths, sinks, or the like for remote control of taps remote control of taps or the like per se F16K

Abstract

A control circuit for flow control of liquid into a scrub sink wherein a differential amplifier is provided with an adjustable input signal based on the ambient condition and an input signal from a photocell which is mounted on the exterior of the edge of the scrub sink. An electrically responsive valve is in the flow line. The torso of the user contacts the photocell to initiate flow into the scrub sink

Claims

1. A dark-initiated liquid flow control circuit wherein an electrical signal responsive valve is included in a liquid flow line, said circuit comprising:

a) a first differential amplifier having first and second input terminals and an output terminal;

b) a level-setting circuit coupled to the first input terminal for establishing a reference light level;

c) a light-responsive component having a dark impedance state, said component being coupled to be second input terminal;

d) means for coupling the level-setting circuit and the light-responsive component to a supply voltage;

e) a drive transistor coupled to said output terminal for providing an actuating signal to the valve when said component is in the dark impedance state;

f) a second differential amplifier coupled to the input terminals of the first differential amplifier for generating an indicating signal when the actuating signal is provided to the valve; and

g) a light-emitting diode coupled to the second differential amplifier and responsive to the indicating signal.

2. The control circuit in accordance with claim 1 wherein said means for coupling the level-setting circuit and the light-responsive component to a supply voltage comprise:

a) a rectifier coupled to an ac supply voltage; and

b) a voltage regulator to establish a dc supply voltage.

3. The control circuit in accordance with claim 2 further comprising a transformer coupled between an ac source and the rectifier.

4. The control circuit in accordance with claim 1 wherein said light-responsive component is a photocell.

5. The control circuit in accordance with claim 4 wherein said level-setting circuit includes a variable resistor.

6. The control circuit in accordance with claim 5 wherein said means for coupling the level-setting circuit and the light-responsive component to a supply voltage comprise:

a) a rectifier coupled to an ac supply voltage; and

b) a voltage regulator to establish a dc supply voltage.

7. The control circuit in accordance with claim 6 further comprising a capacitor coupled to the voltage regulator for transient suppression.

8. A scrub sink of the type providing hands-free user control of liquid flow comprising:

a) a tub having proximal and distal edge portions;

b) a discharge spout coupled to a fluid flow line and spaced adjacent to the distal edge of the tub;

c) an electrically-responsive valve located in the liquid flow line to control the flow into the tub;

d) a photosensitive cell having light and dark impedance states mounted on the proximal edge portion of the tub;

e) a control circuit which includes;

i. a differential amplifier circuit having first and second input terminals and an output terminal, the photosensitive cell being connected to the second terminal,

ii. an adjustable resistor connected to the first terminal,

iii. a power supply connected to the photosensitive cell and the adjustable resistor,

iv) a second differential amplifier coupled to the input terminals of the first differential amplifier for generating an indicating signal when the actuating signal is provided to the valve,

v) a light-emitting diode coupled to the second differential amplifier and responsive to the indicating signal, and

f) a relay coupled between the electrically-responsive valve and the output terminal of the differential amplifier, the placing of the photosensitive cell in the dark impedance state actuating the relay to open the valve and initiate flow.

9. The scrub sink of claim 8 wherein said photosensitive cell is mounted on the exterior surface of the proximal edge portion of said tub to facilitate contact with the user.

10. The scrub sink of claim 9 wherein said relay is open when the photosensitive cell is in the light state and further comprising a drive transistor connected to the output terminal of the differential amplifier for providing a drive signal to close the relay.