CN201051024Y - Novel temperature induction cable - Google Patents

Abstract

The utility model discloses a novel temperature-sensing cable. This new type of temperature-sensing cable includes a twisted thermosensitive wire (1) and a negative temperature coefficient thermistor wire (2), as well as an outer sheath (3) wrapped outside the two wires. The thermosensitive wire is made of elastic The metal wire (12) and the heat-sensitive material layer (13) wrapped outside the elastic metal wire are composed; the negative temperature coefficient thermistor wire is composed of the elastic metal wire (22) and the negative temperature coefficient thermistor wrapped outside the elastic metal wire Material (23) Composition. The temperature sensing cable can be used with fire detectors. The new temperature-sensing cable and the temperature-sensing fire detector using the cable are less affected by the ambient temperature, have high precision, and will not cause false alarms.

Description

New temperature sensing cable

technical field

The utility model relates to fire fighting equipment, in particular to a temperature-sensing cable.

Background technique

Cable tunnels, large cable rooms, hydraulic stations, oil depots, oil storage tanks, power distribution systems, warehouses, chemical storage and production plants, and hangars have strict fire protection requirements and require very reliable fire early warning and detection equipment. Commonly used temperature-sensitive fire alarms generally use temperature-sensitive cables as the source of signal collection.

Coaxial temperature-sensing cable is a commonly used temperature-sensing cable, which is generally composed of inner conductor of metal material, negative temperature coefficient (NTC) thermistor material, shielding layer, outer sheath and explosion-proof braided sheath from inside to outside. . Once a fire occurs, the resistance value of the negative temperature coefficient (NTC) thermistor material will change due to the temperature rise. The signal decoder senses this change, converts the signal, and realizes the fire alarm through computer processing.

This kind of coaxial temperature-sensing cable has high accuracy in point value, but the accuracy will become worse when the length increases, and it is more prone to false alarms due to the influence of ambient temperature. A fire alarm will sound. When the length used is large, the accuracy of this type of coaxial temperature sensing cable may not meet the requirements. Therefore, there is a need for a temperature-sensing cable with higher precision and less influence by ambient temperature.

Utility model content

The utility model aims to provide a novel temperature-sensing cable which is less affected by ambient temperature and has high precision.

Achieved through the following technical solutions:

A new type of temperature-sensing cable 4, including a twisted thermosensitive wire 1 and a negative temperature coefficient thermistor wire 2, and an outer sheath 3 wrapped around the two wires;

The heat-sensitive wire is composed of elastic metal wire and a heat-sensitive material layer wrapped outside the elastic metal wire; the negative temperature coefficient thermistor wire is composed of elastic metal wire and a negative temperature coefficient thermistor material layer wrapped outside the elastic metal wire. As shown in Figures 1, 2, and 3.

The tensile strength of elastic metal wire is not less than 1000pa.

The melting temperature of the heat-sensitive material layer is 40°C to 260°C.

The heat-sensitive material can be selected according to the needs. When the melting temperature is reached, the heat-sensitive material will melt, and the wrapped elastic metal wire will contact the wire of the negative temperature coefficient thermistor, and the resistance value will change. The signal decoder can sense this change and send out an alarm when the preset temperature parameter is reached.

The above-mentioned new temperature-sensing cable can be applied to linear temperature-sensing fire detectors. This type of fire detector includes a sensing circuit, a box body and a signal decoder arranged in the box body. The sensing circuit is connected to the signal decoder;

The sensing circuit is composed of the above-mentioned new type temperature sensing cable and terminal box;

The signal decoder includes a preamplifier circuit, an integrated A/D conversion microcontroller, a parameter input circuit, an alarm relay circuit and a display circuit; the input end of the preamplifier is connected to the temperature-sensitive cable, and the output end of the preamplifier and parameter input circuit Connect to the input end of the single-chip microcomputer integrating A/D conversion, and the output end of the single-chip microcomputer integrating A/D conversion is respectively connected to the input end of the alarm relay circuit and the display circuit, as shown in Figure 5.

The alarm relay circuit can choose a multi-level alarm relay circuit, such as a four-level alarm relay circuit.

The display circuit includes an LCD display circuit and an LED display circuit.

The new temperature-sensing cable provided by the utility model, and the fire detector using the temperature-sensing cable, are less disturbed by the ambient temperature, have very high reliability, will not cause false alarms when the fire temperature is not reached, and can be widely used in various environments.

Description of drawings

Figure 1 is a schematic diagram of the structure of the new temperature-sensing cable

Figure 2 is a schematic diagram of the thermal wire structure

Figure 3 is a schematic diagram of the wire structure of a negative temperature coefficient thermistor

Figure 4 is a schematic diagram of the structure of a linear temperature-sensitive fire detector

Figure 5 is a schematic block diagram of a linear temperature-sensitive fire detector

Figure 6 is a circuit diagram of a linear temperature-sensitive fire detector

Among them, 1-thermosensitive wire, 12-elastic metal wire, 13-thermosensitive material layer, 2-negative temperature coefficient thermistor wire, 22-elastic metal wire, 23-negative temperature coefficient thermistor material layer, 3- Outer sheath, 4-new temperature sensing cable, 5-terminal box, 6-box body, 7-signal decoder

Detailed ways

Example 1

The heat-sensitive wire is composed of elastic metal wire and the heat-sensitive material layer wrapped outside the elastic metal wire, as shown in Figure 1; the negative temperature wire is composed of elastic metal wire and the negative temperature coefficient thermistor material layer wrapped outside the elastic metal wire coefficient thermistor wires, as shown in Figure 2.

Twist the above-mentioned thermal wires and negative temperature coefficient thermistor wires to form a twisted pair, and wrap a layer of outer sheath on the outside to form a new type of temperature-sensing cable, as shown in Figure 3.

The tensile strength of elastic metal wire is not less than 1000pa. The melting temperature of the heat-sensitive material layer is 40°C to 260°C. Applicable heat-sensitive materials can be selected according to the actual situation.

Example 2

A linear temperature-sensitive fire detector is composed of a sensing circuit, a box body 6 and a signal decoder 7 arranged in the box body, as shown in FIG. 4 . Connect the new temperature-sensing cable in Example 1 to the terminal box 5 to form a sensing circuit.

The signal decoder includes a preamplifier circuit, an integrated A/D conversion microcontroller, a parameter input circuit, and an alarm relay circuit display circuit; the input end of the preamplifier is connected to the temperature-sensing cable, and the output end of the preamplifier circuit and the parameter input circuit The input end of the integrated A/D conversion single-chip microcomputer is connected, and the output end of the integrated A/D conversion single-chip microcomputer is respectively connected with the input end of the multi-level alarm relay circuit and the display circuit. As shown in Figure 5. The display circuit includes an LCD display circuit and an LED display circuit.

The above-mentioned integrated A/D conversion single-chip microcomputer selects the high-performance single-chip microcomputer of MICROCHIP Company, and its model is PIC16FC74, with internal A/D conversion, 4K FLASHROM, and simplified instruction set. All signal collection, signal conversion, signal judgment and signal output functions are completed by the single chip microcomputer.

The alarm relay circuit is a four-level alarm relay circuit, including a first-level alarm relay circuit, a fault relay circuit, a second-level alarm relay circuit, and a third-level alarm relay circuit. The alarm relay circuits at all levels are composed of resistors, optical couplers, relays and forward diodes, wherein the resistors are connected in series with the P-level of the diode in the optocoupler, the N-level of the diode is grounded, and the P-level of the triode in the optocoupler is connected to the ground. Voltage, N-level relays in series, and relays in parallel with forward diodes. The circuit diagram is shown in Figure 6.

Claims (3)

1. a novel temperature sensing cable (4) is characterized in that, comprise strand around temperature-sensitive lead (1) and negative tempperature coefficient thermistor lead (2), and be wrapped in oversheath (3) outside these two leads;

The temperature-sensitive lead is by elastic metallic yarn (12) and be wrapped in the outer heat-sensitive material layer (13) of elastic metallic yarn and form; The negative tempperature coefficient thermistor lead is by elastic metallic yarn (22) and be wrapped in the outer negative temperature coefficient heat-sensitive resistance material layer (23) of elastic metallic yarn and form.

2. the described a kind of novel temperature sensing cable of claim 1 is characterized in that, described heat-sensitive material layer melt temperature is 40 ℃～260 ℃.

3. the described a kind of novel temperature sensing cable of claim 1 is characterized in that described elastic metallic yarn tensile strength is not less than 1000pa.

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