Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2001-09-24
2003-04-22
Lieu, Julie (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S581000, C340S517000, C340S521000
Reexamination Certificate
active
06552664
ABSTRACT:
TECHNICAL FIELD
The present invention is related to a method of fabricating a fire detector, and more particularly to a method of fabricating various types of fire detectors by selecting a combination of common units, and to fire detectors thus fabricated.
BACKGROUND ART
There have been proposed a wide variety of fire detectors designed for specific purposes or situations. In terms of a fire sensing elements, the fire detectors can be classified generally into three types of using a smoke sensor, a thermal sensor, and a combination thereof. Also, the fire detectors can have different schemes of determining an outbreak of fire or fire-presence, for example, by analyzing a sensed parameter of the smoke density and/or temperature in accordance with a sophisticated program, or simply by comparing the parameter with a reference value. Further, the fire-presence signal may be simply a short-circuit signal on a transmission line to a receiver, or may carry address assigned to each detector for precisely locating the presence of fire at the receiver. Therefore, depending on specific particular needs in consideration of a scale of fire detection system, an environment, cost and other factors, the detector is selected from a large number of combinations of the sensing elements, the fire-presence determination schemes, and the transmission of the fire-presence signal. The detectors of different specifications have been fabricated individually as different models in conformity with various needs. However, the different models are normally designed to have exclusive parts some of which are not shared with other models. This becomes critical when most of the parts of the detector are integrated into a single chip. Therefore, a manufacture has to prepare and stock a large kinds of exclusive parts for production of various types of the detector, which leads to a cost increase of the fire detector.
DISCLOSURE OF THE INVENTION
In view of the above problem, the present invention has been accomplished to provide a method which enables to fabricate various models of fire detectors only from a limited number of common parts or units. Therefore, it is a primary object of the present invention to provide a method which is capable of producing various models of fire detectors in accordance with user's specific needs at a reduced cost. The method in accordance with the present invention utilizes a smoke sensor unit
1
, a thermal sensor unit
2
, a signal processing unit
3
, a signal transmission unit
4
, and a power unit
5
, and then combines at least one of the smoke sensor unit and the thermal sensor unit with the power unit and optionally with at least one of the signal processing unit and the signal transmission unit.
The smoke sensor unit is provided to sense a smoke density and generate a smoke density signal indicative thereof, in addition to generating a fire-determination signal indicative of the fire-presence or not as determined based upon the sensed smoke density. The smoke sensor unit includes a power input terminal T
11
for receiving an operating voltage, a smoke density output terminal T
13
for providing the smoke density signal, and a fire-determination output terminal T
14
for providing the fire-determination signal.
The thermal sensor unit
2
is provided to sense an environmental temperature and generate a temperature signal indicative thereof. The thermal sensor unit includes a power input terminal T
21
for receiving the operating voltage, and a temperature output terminal T
22
for providing the temperature signal.
The signal processing unit
3
is provided to determine the fire-presence based upon any of the smoke density signal and said temperature signal, and to generate a fire-determination signal. The signal processing unit has a smoke density input terminal T
33
for receiving the smoke density signal, a temperature input terminal T
32
for receiving the temperature signal, a fire-determination output terminal T
34
for providing the fire-determination signal, an interrogation signal input terminal T
35
for receiving an interrogation signal, and a power input terminal T
31
for receiving the operating voltage.
The signal transmission unit
4
is responsible for signal transmission with a receiver
6
and is configured to convert the fire-determination signal into a multiplex signal for multiplex transmission to the receiver, and to transform the interrogation signal from the receiver into a suitable format to be processed at the signal processing unit
3
. The signal transmission unit has a power input terminal T
41
for receiving the operating voltage, an interrogation input terminal T
45
for receiving the interrogation signal, a fire-determination input terminal T
42
for the fire-determination signal, an interrogation signal output terminal T
43
for transmitting the interrogation signal, and an multiplex signal output terminal T
46
for transmitting the multiplex signal to the receiver through the power unit.
The power unit
5
is provided to give the operating voltage and includes a switch circuit
18
which is connected to the receiver for providing a short-circuit signal when the fire-determination signal indicates the fire-presence. Also included in the power unit is a transfer circuit
52
which transfers the interrogation signal from the receiver to the signal transmission unit as well as the multiplex signal from the signal transmission unit to the receiver. The power unit has a power output terminal T
51
for providing the operating voltage, a multiplex signal input terminal T
56
for receiving the multiplex signal, an interrogation output terminal T
55
for providing the interrogation signal, a fire-determination input terminal T
54
for receiving the fire-determination signal, and a port T
52
, T
53
for connection with the receiver.
Since each unit is configured to have the input and output terminals for immediate connection with those of a corresponding unit or units, the detector in any desired combination of the units can be readily assembled.
In a preferred embodiment, at least one of the smoke sensor unit, the thermal sensor unit, the signal processing unit, the signal transmission unit, the power unit is prepared In the form of an integrated circuit for facilitating the assembly of the detector, in addition to making the detector compact.
One example of the fire detector fabricated in accordance with the present invention is equipped with all the units
1
to
5
, in which the smoke sensor unit
1
has the smoke density output terminal T
13
connected to the smoke density input terminal T
33
of the signal processing unit
3
, the thermal sensor unit
2
has the temperature output terminal T
22
connected to the temperature input terminal T
32
of the signal processing unit
3
, the signal processing unit
3
has the fire-determination output terminal T
34
connected to the fire-determination input terminal T
42
of the signal transmission unit
4
, the signal processing unit
3
has the interrogation input terminal T
35
connected to the interrogation output terminal T
43
of the signal transmission unit
4
, the signal transmission unit
4
has the multiplex signal output terminal T
46
connected to the multiplex signal input terminal T
56
of the power unit
5
, the signal transmission unit
4
having the interrogation input terminal T
45
connected to the interrogation output terminal T
55
of the power unit
5
, and the power unit
5
has the power output terminal T
51
connected to the power input terminals T
11
, T
21
, T
31
, and T
41
of the smoke sensor unit, the thermal sensor unit, the signal processing unit, the signal transmission unit.
These and still other objects and advantageous features of the present invention will become more apparent from the following description of the embodiment when taken in conjunction with the attached drawings.
REFERENCES:
patent: 6014076 (2000-01-01), Luzzader
patent: 6075447 (2000-06-01), Nightingale et al.
patent: 6114967 (2000-09-01), Yousif
patent: 6344802 (2002-02-01), Otsuka et al.
pat
Kawano Yasuyuki
Kirihata Shinji
Nishikawa Takayuki
Oka Shoichi
Sakamoto Koji
Lieu Julie
Matsushita Electric & Works Ltd.
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