JPH0422278Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of an insertable temperature sensor for air conditioning that detects temperature using the oscillation frequency of a crystal oscillator and transmits the detected temperature as a data signal to a transmission line.

Traditional temperature sensors simply had the function of detecting temperature and sending it as an electrical signal, but in recent years, temperature sensors have been used to simplify system configurations and reduce the amount of wiring between air conditioning control devices. Sensors with data signal transmission and reception functions are being developed, and a "temperature sensor" (Patent Application No. 161192 of 1982) was filed separately by the applicant.
has now been disclosed.

However, if such a temperature sensor is to be put into practical use as an insertion type, it is necessary to house a crystal oscillator for temperature detection in the tip of the probe, and also to prevent moisture and disconnection of the wiring. There is a growing demand for a moisture-proof and disconnection-proof structure that can simultaneously achieve these goals.

The purpose of the present invention is to completely satisfy such conventional demands, and the crystal oscillator for temperature detection is housed in a metal sleeve disposed at the tip of the probe, and the inside of the crystal oscillator is housed with heat conductivity. Provided is an extremely effective structure of an insertion type temperature sensor for air conditioning, which is filled with a filler having insulating and moisture-proof properties to prevent moisture in the crystal oscillator and wiring, and to prevent disconnection of the wiring. It is something.

Hereinafter, details of the present invention will be explained with reference to a cutaway side view of a main part showing an embodiment.

In the figure, a probe 1 is composed of a metal sleeve 2 disposed at its tip and a pipe 4 made of phenol resin or the like connected to the metal sleeve 2 via a bushing 3. A crystal oscillator 5 for detecting temperature is housed in the oscillator 5, and a pulse generator 6, which is an integrated circuit for generating clock pulses, is housed adjacent to the crystal oscillator 5.

However, the clock pulse is used for the conversion circuit that converts the output of the oscillation circuit combined with the crystal oscillator 5 into temperature, and for the operation of various circuits. In order to cancel the measurement error due to the frequency of the oscillator,
A crystal oscillator 5 and a pulse generator 6 are provided adjacent to each other.

In this case, aluminum is used for the metal sleeve 2, and an alumite film is formed as an insulating film on the entire surface to ensure heat conductivity and insulation. A ring-shaped groove 2a is formed inside, into which a disk-shaped shield plate 7 made of an elastic metal such as phosphor bronze is press-fitted to prevent noise from being introduced into the interior from the opening.

Further, the lead wires of the crystal oscillator 5 are connected to the terminals 6a and 6b of the pulse generator 6, but the terminals 6a and 6b are directly connected to the terminals 6c and 6d internally, and While connected to the inner conductor 8a and outer conductor 8b of the coaxial cable 8, the electric wire 9a connected to the terminal 6e connects a common circuit separate from the power supply circuit and ground, and also connects to the terminals 6f and 6g. Clock pulses from the pulse generator 6 are transmitted through conductors 9b and 9c of the connected coaxial cable 8'.

In addition, the terminal 6h is internally connected directly to the terminal 6f, the shield plate 7 is connected to the terminal 6h by the electric wire 9d, and the metal sleeve 2 and the shield plate 7 are in contact within the groove 2a. Since they are electrically connected, they are connected to a common circuit, providing a good shielding effect for the internal circuits.

However, the inside of the metal sleeve 2 and the outside of the shield plate 7 are filled with a filler 10 such as an epoxy resin that has heat conductivity, moisture proofing properties, and insulating properties, and protects each internal component and wiring. It prevents movement and prevents disconnection accidents, improves heat transfer to each component, provides good responsiveness to detected temperatures, and is completely moisture-proof.

Meanwhile, the base of the pipe 4 is screwed into the probe 1.
The casing 11 supporting the casing 11 is composed of a base 12 made of a heat insulating material such as resin and a cover 13, and screws 13a and 1 are screwed into bosses 12a and 12b formed to protrude inward from the base 12.
3b, a printed circuit board 15 equipped with an oscillation circuit combined with the crystal oscillator 5, a conversion circuit that converts the output of the oscillation circuit into temperature, a transmission circuit that transmits the output of the conversion circuit as a data signal to a transmission path, etc. The mounted printed circuit board 14 is fixed.

In addition, the coaxial cable 8 and the conductors 9b and 9c which penetrate the bushing 3 and are inserted into the pipe 4
The coaxial cable 8' and the electric wire 9a are
It penetrates the bushing 16 provided at the boundary between the base 12 and the pipe 4, the shield plate 17, and the printed circuit boards 14 and 15, and the printed circuit board 1
4, 15, the connecting fittings 14a, 14b,
14c, 15a, and 15b by soldering, and the coaxial cable 8 connects the crystal oscillator 5 and the printed circuit board 15, and the electric wire 9
The pulse generator 6 and the printed circuit board 14 are connected by a coaxial cable 8' consisting of a conductor 9a and conductors 9b and 9c.

However, when the probe 1 is inserted into the test area,
A temperature difference occurs between the inside of the probe 1 and the inside of the housing 11, and moisture in the air moves into the housing 11 due to the breathing action through the pipe 4, causing dew condensation on the printed circuit boards 14 and 15. Since there is a risk of deteriorating the electrical characteristics, a filler 18 similar to the filler 10 is heaped up in an airtight manner at the boundary between the pipe 4 and the casing 11 to seal this area.

In addition, when inserting probe 1 into the fluid,
A stainless steel watertight pipe or the like may be attached to the probe 1, and a connector or the like may be used in place of the bushing 3. If high measurement accuracy is not required,
The same effect can be achieved even if the pulse generator 6 is housed in the housing 11, and the metal sleeve 2 may be made of a metal with good heat conductivity such as brass or copper, and the shield plate 7 may be omitted depending on the situation. The present invention can be modified in various ways.

As is clear from the above explanation, according to the present invention, with a simple configuration, the crystal resonator, the pulse generator, and the wiring therefor housed in the tip of the probe are completely moisture-proofed, and at the same time, Disconnection is reliably prevented, and condensation on the printed circuit board containing the conversion circuit and transmission circuit housed in the housing is completely prevented, and stable temperature detection is performed, making it ideal for air conditioners with crystal oscillators. A great effect can be obtained in the insertion type temperature sensor.

[Brief explanation of the drawing]

The figure is a cutaway side view of essential parts showing an embodiment of the present invention. 1...Probe, 2...Metal sleeve, 3...
Bushing, 4...pipe, 5...crystal oscillator,
10...Filling material.

Claims (1)

[Claims for Utility Model Registration] A crystal oscillator for temperature detection, an oscillation circuit combined with the crystal oscillator, a conversion circuit that converts the output of the oscillation circuit into temperature, and a data converter that converts the output of the conversion circuit into temperature. An air conditioning insertable temperature sensor having a transmission circuit for transmitting a signal to a transmission path, comprising: a crystal oscillator housed in the tip of a probe; a pulse generator connected adjacent to the crystal oscillator; a metal sleeve that accommodates the oscillator and the pulse generator and is arranged at the tip of the probe; an epoxy filler filled in the metal sleeve; and a metal sleeve that supports the probe and also supports the conversion circuit and the transmission circuit. an air conditioning insert type, comprising: a housing made of a heat insulating material that accommodates a printed circuit board mounted with the probe; and a filling material that airtightly seals a boundary between the inside of the housing and the inside of the probe. Structure of temperature sensor.