US3569964A

US3569964A - Supervisory alarm systems

Info

Publication number: US3569964A
Application number: US729768A
Authority: US
Inventors: Irving Mande
Original assignee: Edwards Co Inc
Current assignee: Edwards Co Inc
Priority date: 1968-05-16
Filing date: 1968-05-16
Publication date: 1971-03-09
Anticipated expiration: 1988-03-09

Abstract

A supervisory alarm system is disclosed for a normally supervised alarm detection circuit actuated in response to energization from a commercial source of power. A plurality of alarm condition sensing devices is connected in multiple in the circuit and includes supervisory and alarm detection means including supervisory and alarm relays connected in series in the circuit for respectively sensing trouble and alarm conditions. Power failure detection means responsive to the failure of the source of power deenergizes the supervisory relay until power from the commercial source is restored and a control means is effective in response to the power failure detection means for energizing the circuit from a standby battery.

Description

United States Patent [72] Inventor Irving Mande 2,736,012 2/1956 Bland 340/409 Westport, Conn. 3,448,447 6/1969 Tetherow 340/409 5 123;? 1968 Primary ExaminerThomas B. Habecker 9 Patented Mar. 1971 Attorneys Harold S. Wynn and Jeremiah J. Duggan [73] Assignee Edwards Company, Inc.

Norwalk, Conn.

. ABSTRACT: A supervisory alarm system is disclosed for a [54] SUPERVISORY ALARM SYSTEMS normally supervised alarm detection circuit actuated in 8 Claims, 2 Drawing Figs response to energizatlon from a commercial source of power. A plurality of alarm condition sensing devices is connected in [52] U.S. Cl. 340/409, multiple i the circuit and includes Supervisory and alarm 340/ 333 tection means including supervisory and alarm relays con- [51] Int. Cl. G08!) 29/00 nected in series in h circuit f respectively sensing trouble Fleld ofsalcll no and alarm conditions Power failure detection means respon- 333 sive to the failure of the source of power deenergizes the supervisory relay until power from the commercial source is [56] References cued restored and a control means is effective in response to the UNITED STATES PATENTS power failure detection means for energizing the circuit from 2,067,653 1/1937 Witmer 340/333 4 a standby battery.

ALARM DETECTION CIRCUIT AAR "LL TL .UK I

PATENTED mm 9 Ian SHEET 2 OF 2 N wc V INVENTOR I MANDE HIS AGENT P526 205857: 2E3 Q NM NW A. $925 6 6 vm Fl 52m surnnvrsonr ALARM srsrnivis While the invention is subject to a wide range of applications, it is especially suited for use in supervisory alarm systems and will be particularly described in that connection. it more particularly pertains to such systems wherein means are provided for saving power under conditions of operation from a standby battery.

It is a requisite in some fire alarm systems used, for example,

generally energized at a relatively low level to maintain a supervisory, or trouble, relay normally energized to check continuity of the circuit. The energy source of these circuits is generally a commercial source of power with a standby battery that is used at time of commercial power failure. It is thus necessary that the battery be relatively large capacity to ensure sustained operation of the system during a prolonged period of loss of the source of commercial power.

An object of the present invention is to provide a supervisory alarm system wherein a normally energized supervisory detection means is deenergized during a power failure condition when the system is subject to energization from a standby battery.

SUMMARY OF INVENTION The present invention provides a supervisory alarm system for a normally supervised alarm detection circuit. This circuit is normally actuated in response to energization from commercial source of power and includes a plurality of alarm-condition-sensing devices connected in multiple in a circuit. Supervisory and alarm detection means including supervisory and alann relays connected in series in the circuit sense trouble and alarm conditions respectively while power failure detection means responsive to the failure of the source of power deenergizes the supervisory relay until power from the commercial source is restored. Control means is effective in response to the power failure detection means to energize the circuit from a standby battery.

The power failure detection means not only substitutes a standby batteryfor the commercial source of power, but conserves energy under power failure conditions by deenergizing the supervisory relay. A trouble condition is already indicated by power failure detection means and thus the supervisory relay is no longer needed until commercial power is restored.

For a better understanding of the present invention, together with other further objects thereof, reference is had to the following description, taken in connection with the accompanying drawings, while its scope will be pointed out in the appending claims.

FIG. ll illustrates schematically a supervisory alarm system according to one embodiment of the present invention.

FIG. 2 illustrates schematically a supervisory system according to another embodiment of the present invention.

With reference to the accompanying drawings, terminals (BX) and (CX) are connected to an alternating current commercial source of power, thus these terminals are energized except under commercial power failure conditions. This power is used to charge a battery it) (see FIG. ll) through a full-wave rectifier fl and a stepdown transformer R2. The battery llll energizes an alarm detection circuit having wires 23 and id to which one or more alarm condition sensing devices 115 are connected. Supervisory and alarm detecton relays K2 and Kl respectively are connected in series in wire M of the alarm detection circuit for respectively manifesting trouble and alarm conditions.

With reference to FlG. l, a normally energized power failure relay PFK is connected across the source of commercial power terminals (BX) and (CX). The power failure relay PFK is used to selectively permit energization of or deenergization of the supervisory relay K2 in accordance respectively with the energized or deenergized condition of the commercial source of power at the terminals BX) and (CX An alarm circuit is also provided according to FIG. I having wires 16 and 17 which are energized from the battery 10. The alarm circuit has one or more'alarrn devices 18, such as bells or other alarm indicating devices connected between the wires 16 and 17.

The alarm indication circuit of FIG. 1 is supervised by a trouble relay K3 which is connected in series in wire 17. A trouble indicator lamp TE and a trouble bell or buzzer TB are associated with the supervisory relay K3 for manifesting detection by the supervisory relay K3 of a trouble or alarm condition. A suitable switch 19 is provided for use in silencing the buzzer TB. Similarly, a lamp TEl and a buzzer TBI and a switch 20 are associated with the supervisory relay K2 for manifesting trouble in the alarm detection circuit. It is to be understood that the trouble lamps and buzzer control means of both circuits could be combined to provide a single lamp and buuer that is controlled by either relay K3 or relay K2 in accordance with the requirements of practice. Further consideration of the organization of the supervisory alarm system will be made when discussing the mode of operation.

To consider the mode of operation of the preferred embodiment of the supervisory alarm system illustrated in FIG. 1, the conditions will first be described which are considered as normal for the system wherein no trouble is detected and the alarm devices 15 are in their normally open conditions. Also under the assumed normal conditions, a commercial source of power is applied to the terminals (BX) and (CX), and thus the battery 10 is maintained in a charged condition and the power failure relay PFK is maintained normally energized. With relay PKF in its picked-up position, the alarm detection circuit is energized by a current sufficient to maintain the contacts of relay K2 in their picked-up position but insufficient to pick up the contacts of relay Kl. This circuit extends from the positive terminal of battery 10 through front contact 21, of relay PFK, wire l3, resistor 22, diode 23, wire 14, alarm relay Kl, trouble relay K2, and front contact 24 of relay PFK to the negative terminal of battery 10. Similarly, the alarm indication circuit is normally energized from the positive terminal of battery 10 through front contact 25 of relay PFK, back contact 26 of relay Kl, wire 16, resistor 27, diode 2%, wire 17, back contact 29 of relay Kl and winding of relay K3, to the negative terminal of battery 10.

If one of the alarm condition sensing devices 15 of HO. 1 closes its contacts when the normal conditions just described have been effective, the closing of the contacts of the device 15 shunts the resistor 22 and the diode 23 out of the alarm detection circuit to cause a higher level of current to flow in the detection circuit so as to actuate the contacts of relay Kl to their pickup positions. Such actuation pole changes the alarm indication circuit by the actuation of

contacts

26 and 29 so that the alarm indication devices 18 are energized through respective diodes 30. These diodes prevent energization of the alarm indication devices i8 when the normal supervisory energy is applied to the alarm indication circuit. Under alarm conditions, the diode 28 prevents current flow between wires 16 and i7 through resistor 27.

The picking up of relay Kl upon actuation for alarm detection deenergizes relay K3 by opening back contact 29, and the dropping away of relay K3 closes a circuit through its back contact 311 to energize the lamp TE and the buzzer TB, thus calling the attention of the alarm condition to the attention of an operator. The operator may silence the alarm by actuation of the switch l9 to its right-hand position. if it is undesirable to provide a trouble indication as has been described under dicators can be prevented by contacts on relay Kl.

It will be readily apparent that the supervisory relay K3 can be operated upon loss of continuity of the alarm indication circuit to indicate a trouble condition when the conditions of the system have been normal, and similarly the lack of continuity in the alarm detection circuit can be indicated by the dropping away of relay K2.

The supervisory relays K2 and K3 (see FIG. 1), although operating on a relatively low current, would continuously draw energy from the battery under commercial power failure conditions, and thus it is desired that the supervisory check of the alarm detection circuit and of the alarm indication circuit be made only when energy is available from a commercial source of power. Upon failure of this source, the power failure relay PFK becomes dropped away, and the dropping away of this relay renders inactive the supervisory relays K2 and K3 but maintains the alarm

detection circuit wires

13 and 14 energized with a reverse polarity that will not provide current circulation through diode 23. By this organization, it will be readily apparent that the actuation of an alarm condition sensing device 15 to close its contacts, when there has been a commercial power failure, will cause the picking up of the alarm detection relay Kl to energize the alarm indication circuit and the alarm indication devices 18 in a manner which has been described when the system was assumed to have a commercial source of power. It will be noted that the power failure relay PFK pole changes the alarm detection circuit at

contacts

21 and 24, while it only removes normal polarity of energization of the alarm indication circuit by the opening of front contact 25, the pole changing of the alarm circuit being controlled only by the alarm detection relay K1 in a manner which has been described. The drop away of relays K2 and K3 upon the failure of the commercial source of power indicates a trouble condition, and the buzzers TBI and TB can be silenced by actuation of the

switches

19 and 20 to their right-hand positions.

The restoration of the commercial source of power to the terminals (BX) and (CX) causes the picking up of relay PFK and the restoration of the supervisory alarm system to nonnal conditions, except that it is necessary for an operator to actuate the

switches

15 and 20 to their left-hand positions to silences the buzzers TB and TB! which become energized through

front contacts

31 and 32 of relays K3 and K2 respectively upon restoration of the source of energy.

A modified form of the invention is illustrated in FIG. 2 which also discloses respective alarm detection and alarm indication circuits. This embodiment differs from the embodiment of FIG. 1 in that no pole changing is required in either the alarm detection circuit or the alarm indication circuit.

With reference to FIG. 2, terminals (BX) and (CX) are connected to an alternating current commercial source of power. Energy from this source is applied through a transformer 50 and a full-wave rectifier 51 to an alarm detection

circuit having wires

52 and 53. A power failure relay lPFK is connected across the output of the rectifier 51, and thus this relay is normally energized. A standby battery 54 is maintained charged by a suitable battery charger 55. At times of power failure, the battery 54 is connected to

wires

52 and 53 through

back contacts

56 and 57 ofrelay IPFK.

Supervisory and alarm detection relays 1K2 and IX] respectively are normally included in a circuit extending from the positive terminal of rectifier 51 through front contact 56 of relay lPFK, wire 52, front contact 58 of relay lPF K, resistor 59, front contact 60 of relay lPFK winding of relay 1K1, winding of relay 1K2, and front contact 57 of relay lPFK to the negative terminal of rectifier 51. Because of the resistor 59 being normally included in this circuit, the level of energization is such as to permit the relay 1K2 to be picked up, but the relay 1K1 remains in its deenergized position. Normally open circuited detector sensing devices 61 are connected in multiple across the alarm detection circuit, and the general mode of operation of the circuit for alarm detection and trouble indication is similar to that which has been heretofore described relative to the embodiment shown in FIG. 1.

The alarm indicationcircuit of FIG. 2, however, ditferes from the alarm indication circuit illustrated in FIG. 1 in that the alarm indicating devices 62 are includedin the circuit in series. The alarm indication circuit of FIG. 2 comprises

wires

63 and 64, and the circuit is normally energized from the positive terminal of the rectifier 51 through the winding of supervisory relay 1K3, alarm indication devices 62 in series, wire 64, variable resistor 65, front contact 66 of relay IPFK and resistor 67 to the negative terminal of rectifier 51. Resistor 65 is adjusted in accordance with the number of devices 62 in the circuit. Under conditions of alarm detection, the picking up of relay 1K1 shunts the winding of relay 1K3 out of the circuit just described upon the closure of front contact 68 of relay 1K], and the closure of front contact 69 of relay 1K1 causes the pulsing of relay lKlP by energization of the winding of that relay through its back contact 70 in order to intermittently shunt front contact 66 of relay IPF K and resistor 67 out of the alarm indication circuit.

Under conditions of power failure, when the system is employed as disclosed in FIG. 2, the opening of

front contacts

58 and 60 of relay lPFK opens the alarm detection circuit at the point of termination to deenergize the supervisory and alarm relays 1K2 and 1K1. The standby battery 54 is now connected to the

wires

52 and 53 through

back contacts

56 and 57 of relay IPFK, and thus although the alarm detection circuit is open at the point of termination, the. actuation of an alarmcondition-sensing device 61 will be operable to actuate the alarm detector relay 1K1 and to energize the alarm indication circuit through front contact 71 of relay lKIP. The supervisory relay 1K3 in the alarm indication circuit is deenergized under power failure conditions when the relay 1K1 is in its deenergized position by the opening of the alarm indication circuit at front contact 66 of relay lPFK. It is to be understood that the supervisory relays 1K2 and 1K3 can have associated therewith trouble indication apparatus as is disclosed, for example, in FIG. 1.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifiations may be made therein, without departing from the invention, and it is, therefore, aimed in the appending claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Iclaim:

1. A supervisory alarm system for a normally supervised alarm detection circuit normally actuated in response to energization from a commercial source of power comprising:

a. a plurality of alarm condition sensing devices connected in multiple in the circuit;

b. supervisory and alarm detection means including supervisory and alarm relays connected in series in the circuit for respectively sensing trouble and alarm conditions;

c. power failure detection means responsive to the failure of the source of power for deenergizing the supervisory relay until power from the commercial source is restored; and

d. control means effective in response to the power failure detection means to energize the circuit from a standby battery.

2. The invention according to claim 1 wherein the circuit is a two-wire circuit which is terminated by connection of the two wires through a resistor and additional current limiting means is provided responsive to the power failure detection means for limiting the use of power for supervisory purposes during the time of power failure to a value less than the power necessary to maintain the supervisory relay in its normal actuated position.

3. The invention according to claim 2 wherein the additional current limiting means comprises means for opening the circuit near the point of termination in response to the detection of a power failure by the power failure detection means.

4. The invention according to claim 2 wherein the additional current limiting means comprises a polarized device in terval of failure of the commercial source of power.

7; The invention according to'claim 6 wherein the supervisory relay in one oithecircuits is deenergized by pole chang ing the associated circuit.

8. The invention according to'claim 7 wherein the power failure means selectively pole changes one of the circuits and v the alarm detection means selectively pole changes the other circuit.

Claims

1. A supervisory alarm system for a normally supervised alarm detection circuit normally actuated in response to energization from a commercial source of power comprising: a. a plurality of alarm condition sensing devices connected in multiple in the circuit; b. supervisory and alarm detection means including supervisory and alarm relays connected in series in the circuit for respectively sensing trouble and alarm conditions; c. power failure detection means responsive to the failure of the source of power for deenergizing the supervisory relay until power from the commercial source is restored; and d. control means effective in response to the power failure detection means to energize the circuit from a standby battery.

4. The invention according to claim 2 wherein the additional current limiting means comprises a polarized device in the circuit and means responsive to the power failure detection means for pole changing the circuit.

5. The invention according to claim 1 wherein the alarm detection means comprises means for manifesting alarm conditions by rendering active at least one normally inactive alarm indicating device over an alarm indication circuit.

6. The invention according to claim 5 wherein the alarm indicating circuit comprises a normally energized supervisory relay and means controlled by the power failure detection means for deenergizing both supervisory relays during an interval of failure of the commercial source of power.

7. The invention according to claim 6 wherein the supervisory relay in one of the circuits is deenergized by pole changing the associated circuit.

8. The invention according to claim 7 wherein the power failure means selectively pole changes one of the circuits and the alarm detection means selectively pole changes the other circuit.