Apparatus for controlling device start up and off/on running periods

• US 4,798,971 A
• Filed: 04/14/1987
• Issued: 01/17/1989
• Est. Priority Date: 04/14/1987
• Status: Expired due to Fees

• Current Assignee: J & S Electronics Incorporated
• Original Assignee: J & S Electronics Incorporated
• Inventors: Gravely, Charles T.
• Primary Examiner(s): BEHA JR, WILLIAM
• Application Number:
  US07/038,041
• Time in Patent Office: 644 Days
• Field of Search: 323/323, 323/324, 323/235, 323/236, 323/319, 307/632, 307/643, 307/646, 307/117, 307/141, 110/192, 361/196, 246/10, 246/11, 246/46 R
• US Class Current: 307/141
• CPC Class Codes: F23N 1/002 using electronic means F23N1/04 - F23N1/10 take precedence
• CPC Class Codes: F23N 2223/20 Opto-coupler
• CPC Class Codes: F23N 2225/08 temperature
• CPC Class Codes: F23N 2227/10 Sequential burner running
• CPC Class Codes: F23N 2233/10 forcing air through heat exchangers
• CPC Class Codes: F23N 2235/14 electromagnetically operated
• CPC Class Codes: G05D 23/1913 delivering a series of pulses
• CPC Class Codes: G05D 23/275 with sensing element expanding, contracting, or fusing in response to changes of temperature

Abstract

A forced air gas heating furnace system includes a thermostat having a transformer for converting the typical household 115Vac to a 24V thermostat ac control voltage, and a switch, the thermostat elements connected to the junction of an ac to dc converter, a digital control circuit and a TRIAC. The dc output is connected to a dc voltage regulator which outputs Vcc for a digital control circuit. The gate of the TRIAC is connected to the output of the digital control circuit, and operates in response thereto for selectively triggering the TRIAC for passing the 24Vac transformer control power to a solenoid operated gas valve. The solenoid gas valve is connected between the gas source and the gas burner to control the gas supply to the burner in response to the digital control circuit signal operation of the TRIAC; first on to heat the furnace heat exchanger to an operating temperature, and thereafter off and on for selected periods necessary to maintain the operating temperature of the heat exchanger while conserving gas. The control circuit includes a square wave generator for converting the thermostat 60 Hz 24Vac to square waves for a counter/divider. The counter/divider generates pulses suitable for counters of a dual binary counter counting the pulses for outputting selected timing control signals to a logic circuit (plurality of NOR gates). The logic circuit outputs high/low state signals to a TRIAC driver (opto-coupler) which drives the TRIAC in response to the high/low state output of the logic circuit for controlled operation of the gas furnace.

Claims

1. A control device for a system such as a forced air gas burning central heating system or the like comprising:

a. power means for producing ac voltage for operation of the system and converting ac power to dc power for a control means;

b. gate controlled semiconductor switch means connected to the power means for controlling the connection of ac power to a load; and

c. control means connected to the power means for receiving the dc power, and to the gate controlled semiconductor switch for controlling the operation of the switch means in response to the dc power, said control means including first timing means for producing an initial timing signal for the gate controlled semiconductor switch means to conduct ac power for a first preselected time, and a second timing means for producing alternately first and second timing signals for the gate controlled semiconductor switch after the initial signal to block the flow of ac power to the system for a preselected time, and to conduct ac power to the system for a preselected time, wherein the control means further includes a square wave generator connected to the ac power source for producing a plurality of square wave signals at the frequency of the ac source of power, a frequency divider connected to the square wave generator for producing square wave signals having a preselected frequency, the first timing means connected to the frequency divider for generating the initial timing signal for said first preselected time, and the second timing means includes a frequency counter means connected to the frequency divider for thereafter alternately generating said first timing signals for said preselected time periods and said second timing signals for said preselected time periods for the gate controlled semiconductor switch means.

2. A gas control device according to claim 1 further including a driver means connected to the frequency counter means and to the gate-controlled semiconductor switch means for driving the gate controlled semiconductor switch means responsive to the outputs of the frequency counter means.

3. A gas control device according to claim 2 wherein the frequency counter means includes a plurality of counters connected to the frequency divider for selectively producing a plurality of timing signals, and logic circuitry connected to the plurality of counters for producing responsively to the plurality of timing signals, high/low state signals and wherein the gate-controlled semiconductor switch means driver is connected to the logic means for outputting driver signals corresponding to the selected high/low state signals of the logic means.

4. A gas control device according to claim 3 wherein the logic means is a plurality of NOR gates.

5. A gas control device according to claim 4 wherein the gate controlled semiconductor switch means driver is an opto-coupler.

6. A control device for a system such as a forced air gas burning central heating system or the like comprising:

a. power means for producing ac voltage for operation of the system and converting ac power to dc power for a control means;

b. gate-controlled semiconductor switch means connected to the power means for controlling the connection of ac power to a first load;

c. control means connected to the power means for receiving the dc power, and to the gate-controlled semiconductor switch for controlling the operation thereof in response to the dc power, said control means including first timing means for producing an initial timing signal for the gate-controlled semiconductor switch means to conduct ac power for a first preselected time, and a second timing means for producing alternately first and second timing signals for the gate-controlled semiconductor switch after the initial signal to block the flow of ac power to the system for a preselected time, and to conduct ac power to the system for a preselected time; and

d. an ac bypass means for a second load requiring ac, said ac bypass means including a solenoid operated switch having a solenoid selectively connected to a dc output of the control means, and a switch connected between the ac power source and said second load for bypassing the gate controlled semiconductor switch means in response to the dc output of the control means being turned off to the gate controlled semiconductor switch means and on to the solenoid.

7. A gas control device according to claim 6 wherein the ac bypass means includes a relay having a coil selectively connected to the dc power output of the control means and a switch in operative association with the coil and connected between the second ac load and the ac output terminal.

8. Apparatus for controlling a start up period and constant off and constant on periods for a running time of a device comprising:

a. a switching means for connection to an ac power source; and

b. a timing means for connection to the ac power source and switching means, first for producing a timing signal for start up; and

, secondly, for producing constant off and constant on timing signals for running the device during a running period, said timing means including a square wave generating means for generating square waves corresponding to the frequency of the ac source, a counter/divider means for dividing the square waves into a plurality of timing pulses, a timer connected to the counter/divider for generating timing signals for timing the start up period;

first and second counter means connected to the timing means and counter/divider, said first counter being activated and said second counter being deactivated in response to the timer and counter/divider wherein said first counter means turns on the switching means during an initial start up period, and thereafter the second counter means is activated and the first counter means is deactivated wherein the second counter means is operative to alternatively turn the switching means off for constant off periods and on for constant on periods during a running period.

9. An apparatus for maintaining a start up period and off/on running periods for a device comprising:

a. an ac power source means for supplying ac power;

b. a switching means connected to the ac power source means for switching ac power on and off for device operation;

c. a square wave generating means connected to the ac power source for producing a plurality of square wave signals at the frequency of the ac source of power;

d. a frequency dividing means connected to the square wave generating means for producing square wave signals having a preselected frequency;

e. a timing means connected to the frequency divider for generating an initial timing signal for the switching means wherein ac power is passed for the start up period of the device; and

f. a frequency counter means connected to the frequency divider for alternately generating off/on timing signals of preselected durations for the switching means after start up wherein ac power is alternately blocked and passed to the device for off/on running periods beginning after start up.

10. A control device for regulating the combustion of gas in a central heating system powered by an ac power source operating through a switch, comprising:

square-wave generator means connected to the ac power source for producing a plurality of square wave signals at the frequency of the ac source of power;

frequency counter/divider means for driving the power frequency into suitable clocking pulses for determining preselected timing signals;

decode counter/divider means connected to the frequency/divider for outputting a plurality of time period indicating signals; and

transistor means connected to the decode counter/divider for outputting timing signals to the switch, first to conduct ac power for a preselected time, and thereafter, alternately to block the working ac power for a first preselected time, and to conduct ac power for a second preselected time.