US3614278A

US3614278A - Alarm ciruit

Info

Publication number: US3614278A
Application number: US17769A
Authority: US
Inventors: Charles J Di Noto Jr
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-03-09
Filing date: 1970-03-09
Publication date: 1971-10-19
Anticipated expiration: 1988-10-19

Abstract

A relay circuit, in combination with malfunction controls of a domestic heating system (oil burner) energized by a standard primary control whereby on a malfunction such as low water level, in addition to the shutoff of the oil burner, an alarm circuit is operated for an aural or visual signal.

Description

I United States Patent 1 3,614,278

[72] Inventor Charles J. Di Noto, Jr. [56] References Cited.

103 West Passaic Ave., Rutherford, NJ. UNITED STATES PATENTS 07070 2,274,177 2/1942 Wilson 431/71 X [211 PP 17,769 2 297 821 10 1942 h Filed Mar. 9,1970 W empner 431/15 [45] lamented Oct 19 1971 I Primary Examiner-Carroll B. Don'ty, Jr.

Attorney-Nathaniel Ely [54] ALARM CIRUIT 3 Claims, 1 Drawing Fig.

[52] US. Cl 431/16, ABSTRACT: A relay circuit, in combination with malfunction 431/69, 126/351, 126/388, 122/504.2 controls of a domestic heating system (oil burner) energized [51] Int. Cl. F23n 5/24 by a standard primary control whereby on a malfunction such [50] Field of Search 431/14, 15, as low water level, in addition to the shutoff of the oil burner,

16, 69, 71; 126/388, 374, 351; 122/5042 an alarm circuit is operated for an aural or visual signal.

l I 72/ 4e 1 I 30 K I I f 32 SEC l Pm I f I 34 l I i l 35 5B 54 I M 5a f 96 so i l l J 5 I OIL 25 VALVE 3k moron LOW PRESSURETROL .oic:

HEATER I sec. 1

No.2 I06 I07 (LEFT) INVENTOR. Charles J.DiNOI0,Jr.

A NEY.

ALARM cmurr BACKGROUND OF THE INVENTION In domestic heating systems such as those utilizing the typical oil burner for low-pressure steam generation, the oil burner is responsive to heat demands of a room thermostat or a hot water thermostat in the domestic hot water system.

The steam generated in the furnace is distributed by suitable piping to individual room radiators and when a sufficient temperature is reached as set on the room thermostat, or a sufficiently high temperature is reached in the domestic hot water system, the oil burner controls are cut off.

With such systems, a primary control is provided for the interconnection between the house current 120-240 volts), the oil burner motor, the ignition device, the heat demand thermostats, and the malfunction controls of the low-water sensor, the excessive pressure sensor and such other sensors as may be provided.

It is obvious, in the case of the low water sensor, that the burner motor be shut off promptly if there is insufficient water in the furnace for if the furnace ran without water, it would not only damage the furnace, but also due to the lack of generation of enough steam, the room temperature would not satisfy the preset room temperature thermostat and the burner motor would run without the typical cutout.

In addition to the above low water and excess pressure sensors that operate through the primary control, it is common to provide a stack temperature sensor. This also works through relays in the standard primary control in a manner such that fuel failures or unusual starting delays due, for example, to ignition failure, also will shut off the burner motor. However, in this case, the heat demand thermostat will not, by itself, restart the burner. Usually some reset button is provided in the primary control which requires the operator to come to the primary control, which is mounted in the chimney stack near the furnace, to check out and correct the malfunction, and then to reset the starting circuit.

It is apparent that in the usual malfunction, the homeowner will not know of the event until the house becomes exceedingly cold. If a burner doesnt start, there is no evidence other than that the temperature continues to drop. By the time it has reached a sufficiently low degree, which which might not be noticed by the homeowner in a warm bed, the house may be objectionably, and possibly dangerously cold.

I have now observed that the standard primary controls, such as that manufactured under the name Protectorelay by Minneapolis-Honeywell Company, and particularly Model No. RAI 17A, can be interconnected to a supplemental alarm circuit in a manner to instantaneously report a failure of low water, excess pressure, or burner failure due to ignition or fuel failure, the result of which is the failure to promptly raise the stack temperature on heat demand.

By utilizing the standard primary control I add only a simple relay control box containing two relays, a transformer and an alarm such as a bell. The new control box is connected into the house current (1 -220 volts) and across the primary control safety switch which can be utilized to give a low-voltage current. By the use of a high-impedance coil relay in the low-voltage circuit, the opening of the safety switch will not disturb the operation of other relays in the primary control. The necessary energy response, however, can be used to actuate the alarm.

The alarm itself is wired as by simple bell wire to the control box and is located at a convenient place in the house as near the cellar stairs, in the kitchen or other place where its operation is bound to be noticed. It will be understood that as soon as the malfunction is corrected, the alarm is deenergized.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a diagrammatic sketch of an alarm circuit, in accordance with my invention, shown interconnected to a primary control for a domestic oil burner heating system primarily to produce steam.

DESCRIPTION OF PREFERRED EMBODIMENT In a typical domestic steam-heating system using oil for fuel, there are certain standard elements including the oil burner assembly A including the burner, the motor and the igniter. The standard primary control is represented at B having a stack temperature sensor B which is mechanically attached to relays in the primary control but projects into the chimney stack. Box C represents a standard junction box for the lowwater cutoff sensor and for the pressure-responsive sensor. A room thermostat is shown at D.

The primary control B is nonnally interconnected by lines 14-16-18 with the room thermostat D. The primary control is also connected to the house current (I20-240 volts) through lines 10-12. As shown, however, this is usually accomplished through junction box C with line 10 going through junction box C with line 10 going through the sensor in low-water cutoff 20 and thence through the sensor in pressure control 24 and out through line 26 to terminal 101. The other house current line 12, through line 28 goes to terminal 102. This will energize the primary of transformer 103 at all times.

With a standard primary control of the aforementioned Protectorelay type, there are several relays to perform seriatim operations concerned with the operation of an oil burner assembly. As described by the manufacturer,

contacts

106 and 107, designated cold contacts, are normally in closed position when the burner is idle and contact 108 designated a hot contact, is open, the safety switch I05 is closed and both

relays

98 and 99 are deenergized. Relay 98 is mechanically linked to contact switches 109, I10 and 111 as well as ignition switch 115. In a similar manner, relay 99 is mechanically linked to contact switches 112, I13, 1 14 and burner motor switch 116.

When the thermostat D calls for heatv by closing its

contacts

14 and 16, the relay 98 becomes energized through the secondary of the transformer 117, the closed safety switch 105, the

hot contacts

106 and 107, and the safety switch heater 90.

This, in turn, will not only

close contacts

109, 110, and 111 but will close contact 115 bringing on ignition through the house current circuit 101, terminal 104, line 56 in which is the typical igniter transformer and line 52 to the terminal 102.

A split second later, relay 99 is energized through line 111A, safety switch 105, secondary of transformer 117, line 14, thermostat D, line 16, heater and. contacts 109 (or 110) back to contact 111.

Contacts

112, 113, 114 and burner switch 116 are thus closed starting the motor through terminal 103.

When the temperature in the stack rises, the curved spring in stack sensor B expands moving the arm linkage to

contacts

107 and 106, breaking them in that order, thereby deenergizing relay coil 98 which in turn breaks contacts 109-110-111- 115-, turning off ignition.

As the temperature continues to rise in the stack, contact 108 closes under further movement of the sensor B and as the current then flows through the contacts it ceases to flow through heater 90 of the safety switch 105.

Thus the system is in the run position with relay coil 99 ac tivated and contacts 112-113-114-11I6 are closed with the burner motor running until thermostat D is satisfied.

NEW ELEMENT In accordance with my invention, I provide an alarm circuit in control box 40. A terminal strip 42 is used to facilitate connections. It also includes relay 44, relay 46, transformer 48 and alarm 50. The alarm 50, as previously noted, may be mounted at a remote point and need not be mounted withing the control box 40.

These elements are interconnected as follows:

Terminal 1 serves as a junction for the connection of the house current power source 10, through line 108, with the primary of transformer 48 through line 74.

Terminal 2 serves 2 serves as a junction for the connection of the house current power source 12, through line 12A, with the other side of the primary of transformer 48 through line 72.

Terminal 3 is a junction for the connection of the house current source 10, through line 10A from the center tap between the low-water cutoff sensor 20 and the excess pressure sensor 24 and the operating coil of relay 44. The other side of the coil is interconnected to terminal 2.

The relay 44 is shown with the contacts closed as would be the case with no power on the system. During normal operation, however, the contacts would be open. If there is a malfunction of low water, the coil of relay would become deenergized and hence the contacts would again move to the closed position.

Terminal 4 serves as the junction for

lines

58 and 36 connected to a contact of the relay switch of relay 44 and through line 64 to alarm 50.

Terminal 5 serves as the junction for line 60 interconnected to the safety switch 105 in primary control B, and one side of the coil of relay 46.

Terminal 6 serves as the junction for line 62 interconnected to the safety switch 105 in primary control B, and the other side of coil of relay 46.

Relay 46 is normally deenergized with the switch contacts open. A contact of the switch of relay 46 as well as a contact of the switch of relay 44 are connected by line 34 and line 32 through line 30 with the side of the secondary winding of transformer 48. The coil of relay 46 is of high impedance as will be hereinafter explained.

Terminal 7 serves as the junction for line 66 interconnected to alarm 50 and line 68 connected to the other side of the secondary winding of transformer 48.

A remote alarm, not shown, may be connected, as is alarm 50, with

terminals

4 and 7.

EXAMPLE OF OPERATION If the sensor in low-water control 20 opens due to an unsafe low-water condition, it will break the house current circuit to the primary control as it is in the circuit from line 10, through the control 20 and line 26 to the primary control and returning through line 28 and line 12. in addition, it will deenergize the coil of relay 44, the switch contacts will close, and through line 30 from the secondary of transformer 48, line 32, line 36, line 58, line 64, alarm 50, line 66, and line 68 to the secondary coil, the alarm is energized. It will be noted that although the low-water control 20 breaks the power circuit to the primary control B and hence will stop the burner, it does not discontinue current to the primary of transformer 48 which is energized by lines B and 12A.

An alarm would also be given, through the primary control operation due to a lack of combustion as for failure of ignition or absence of fuel or similar reason after the thermostat D had called for heat.

This results from the failure of the stack sensor B to open

contacts

106 and 107 and close contacts 108. During a preset interval of about seconds, the current flows through heater 90 of the safety switch 105. The metallic strip that holds safety switch closed is thus warped to force the contacts open thus breaking the current flow through

relays

98 and 99. This discontinues all power to the burner assembly.

It is essential that the coil of relay 46 be of high impedance for if not the opening of safety switch 105 would not discontinue the flow of current to relays 98 and 99.

The foregoing description, although drawn primarily to an oil-bumer-activated domestic steam-generating combination, can also be applied, within the concept of the invention, to hot air or hot water systems.

I claim:

1. In combination with an oil burner assembly for a domestic heating system wherein said assembly includes a burner motor, an ignition system and an oil valve, a heat demand thermostat, and a primary control for said oil burner assembly having means reactive to chimney stack temperatures which means include a safety switch which discontinues motor operation on failure of prompt heating of the chimney stack on activation of the heat demand thermostat, and wherein a low-water sensor is interconnected to a house current and said primary control such that on occurrence of low water, the primary control also discontinues motor operation, an alarm circuit including:

a. a transformer interconnected to the house current;

b. an alarm device activated by the transformer;

c. a low-voltage relay system including a high-impedance coil shunted across the safety switch of the primary control, and a switch in the alarm circuit activated by the coil on opening of said safety switch to activate the alarm, said safety switch being opened by the stack responsive means on failure of prompt heating of the chimney stack on normal heat demand of the thermostat.

2. In the combination of claim 1, the added relay system including a house current activated coil and switch, wherein the coil is in circuit with the house current and low-water sensor, and the switch is in the alarm circuit, such coil becoming deenergized on failure of the low-water sensor and thus causing the switch to close and activate the alarm.

3. In the combination of claim 2, the added circuit of an ex cess pressure sensor in the house current, high-voltage relay circuit whereby on opening of the excess pressure sensor on the occurrence of excess pressure, the primary control and the oil burner assembly are deactivated.

Claims

1. In combination with an oil burner assembly for a domestic heating system wherein said assembly includes a burner motor, an ignition system and an oil valve, a heat demand thermostat, and a primary control for said oil burner assembly having means reactive to chimney stack temperatures which means include a safety switch which discontinues motor operation on failure of prompt heating of the chimney stack on activation of the heat demand thermostat, and wherein a low-water sensor is interconnected to a house current and said primary control such that on occurrence of low water, the primary control also discontinues motor operation, an alarm circuit including: a. a transformer interconnected to the house current; b. an alarm device activated by the transformer; c. a low-voltage relay system including a high-impedance coil shunted across the safety switch of the primary control, and a switch in the alarm circuit activated by the coil on opening of said safety switch to activate the alarm, said safety switch being opened by the stack responsive means on failure of prompt heating of the chimney stack on normal heat demand of the thermostat.

3. In the combination of claim 2, the added circuit of an excess pressure sensor in the house current, high-voltage relay circuit whereby on opening of the excess pressure sensor on the occurrence of excess pressure, the primary control and the oil burner assembly are deactivated.