JPS6123955A - Freezing previewing device - Google Patents

Abstract

PURPOSE:To detect the freezing in a feed and discharge pipe in advance by providing a piezoelectric oscillator which transmits vibrations to the freezable liquid in a heat-conductive container and detects the freezing state of the freezable liquid from variation in resonance characteristics. CONSTITUTION:The metallic heat-conductive container 2 which has a space 3 for forming a reservoir for water as the freezable liquid is so formed that the temperature of the feed and discharge pipe 5 is easy to conductor. The metallic container 2 is made of aluminum or copper; and the piezoelectric oscillator 1 which contacts the water in the container 2 is provided on one outside surface and a radiation fin 4 which improves cooling effect is provided on the other outside surface. The metallic container 2 as a freezing detection part is fixed to the outer periphery of the feed and discharge pipe 5 with a freezable liquid injection port 6 up, and water is injected into the space 3 separately from the water in the paper and discharge pipe 5. The diezoelectric oscillator 1 is formed by sticking a piezoelectric element 12 inside the closed end part 13 of a metallic outside pipe 11 so that the oscillator enters flexural oscillations when the piezoelectric element 12 is driven.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention includes a piezoelectric vibrator that operates by taking advantage of the fact that the piezoelectric vibrator is subjected to a large load due to freezing of water, and its resonance characteristics are significantly deteriorated. Regarding freeze predictors.

[Prior art]

An example of the configuration of a prior art freeze predictor is shown.

FIG. 1 is a diagram showing an example of the configuration of a prior art freeze predictor. In the figure, (1) (1 (I is an ultrasonic transmitter and a receiver. The ultrasonic transmitter (1) is provided at one end of a cylindrical container (2) provided with radiation fins (4). The cylindrical container (2) is attached to the wall of the liquid supply and drainage pipe (5).
The cylindrical container (2) must have an inner diameter smaller than the inner diameter of the liquid supply/drainage pipe (5). This is due to the effect of the heat radiation fins (4) as well as the liquid supply and drainage pipe (5).
This is because there are 8 gravels that freeze the inside of the container (2) and the inside (3) earlier than the inside. However, the inner diameter of the container (2) is.

limited by the size of the provided ultrasound transmitter (1).

The drawback was that it interfered with sensitivity adjustment for freezing detection.

Moreover, the internal space (3) of the cylindrical container (2) is.

It becomes a pool of water and is not affected by the flow of water in the supply/drainage pipe (5), but water scale and other mixtures in the water get in.
This results in ultrasonic propagation loss.

This has the disadvantage that it affects the output of the ultrasonic receiver a1 and gives erroneous information.

[Summary of the invention]

This invention was made in order to eliminate the above-mentioned drawbacks, and includes a thermally conductive container filled with a freezing liquid that contacts the liquid supply/drainage pipe and transmits the temperature of the liquid supply/drainage pipe. By equipping the container with a piezoelectric vibrator that transmits vibrations to the freezing liquid in the container and detects the freezing state of the freezing liquid by changes in resonance characteristics, freezing phenomena in the supply and drainage pipes can be detected in advance, The purpose of the present invention is to obtain a freeze predictor having a sensitivity adjustable function.

[Embodiments of the invention]

FIGS. 2(a) and 2(b) are two partial cross-sectional views of a freeze predictor according to an embodiment of the present invention. Figure 2 (C
) is a plan view of the freeze predictor seen from above.

In the figure, (2) has a space (3) for creating a pool of water, which is a freezing liquid, and is a thermally conductive container, in this case a metal container, through which the temperature of the liquid supply and drain pipes is easily transmitted. Metal container (2)
Examples include aluminum and copper. - of metal container (2)
A piezoelectric vibrator (1) in contact with the water of the container is provided on the outer surface, and radiation fins (4) are provided on the other outer surface to enhance the cooling effect. The metal container (2), which is the freeze detection part, has a freezing liquid inlet (6) on the outer periphery of the liquid supply/drainage pipe (5).
) is fixed so that it faces upward.

Water is injected into the space (3) separately from the water in the supply and drain pipe (5).

FIG. 3 is a sectional view showing an example of the configuration of the piezoelectric vibrator +1) according to the present invention.

In the figure, (1) is a piezoelectric element, which is attached to the inside of the closed end 0 of the metal outer cylinder αυ.The closed end has a waterproof effect and is thinly processed, and the piezoelectric element α2 It is designed to cause flexural vibration when driven.The open end of the metal outer cylinder aυ is sealed with a lid I equipped with a terminal tl!9 for taking out the input and output of electrical No. 4j. .

Flexural vibrations are easily affected by loads;

This appears as a change in the resonance characteristics of flexural vibration.

The freeze detection operation will be explained using FIG. 4.

Note that f indicates the wave number of vibration or impedance.

When the ship enters the freeze detection space (3) and the freezing progresses from the inner wall of the space (3) toward the center, the piezoelectric vibrator (1)
), a load is applied to suppress the operation. FIG. 4(a) shows the resonance characteristics of the piezoelectric vibrator (1) before freezing. The resonant frequency fo+ is determined by the outer diameter of the piezoelectric element 02, its thickness, and the wall thickness of the closed part (13).As the load increases, the resonant characteristics deteriorate, and as shown in Fig. 4(b), the resonant frequency f01 shifts to the lower frequency side f02, and resonance impedance 2 increases.When the entire space (3) finally freezes, the load reaches its maximum, and the piezoelectric vibrator If a self-excitation circuit incorporating the piezoelectric vibrator (1) is constructed in which the resonance characteristic (1) is completely suppressed, excitation will stop in the state shown in FIG. 4(c).

In this way, the freezing phenomenon can be clearly grasped. Furthermore, by narrowing the separation between the side wall of the piezoelectric vibrator (1) and the opposing wall, the response can be made faster and the sensitivity of freezing detection can be increased.

It can be adjusted according to the inner diameter of the liquid supply/drainage pipe (5) to be installed, and can flexibly respond to required specifications. Here, the freeze detection space (3) is smaller than the inner diameter of the liquid supply/drainage pipe (5), and contains the freezing liquid within the space (3).

Here, the water is rapidly frozen, allowing the water supply and drainage pipes (
A freezing phenomenon appears before the freezing of the supply and evacuation tube (5).
) freezing prediction becomes possible.

In the above embodiment, water was used as the liquid in the liquid supply/drainage pipe (5) and the freeze detection space (3), but it goes without saying that other liquids may be used.

In addition, in the above embodiment, heat radiation fins were provided to rapidly freeze the freezing liquid in the metal container, but it is possible to do without them by using a material with good heat radiation effect for the material of the metal container. .

This freeze predictor works effectively even when the flow rate in the liquid supply/drainage pipe f5i is small or when the flow stops.

〔Effect of the invention〕

According to this invention, a thermally conductive container filled with a freezing liquid through which the temperature of the liquid supply and drainage pipe is transmitted, and a thermally conductive container that is provided in this thermally conductive container and is provided in the thermally conductive container to prevent vibrations within the container. Since the piezoelectric vibrator is equipped with a piezoelectric vibrator that detects the state of freezing of the freezing liquid based on changes in the resonance characteristics of the freezing liquid, freezing can be detected quickly.

The sensitivity can be adjusted according to specifications, and the advantage is that a compact freeze predictor can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of a prior art freeze predictor, FIG. 2(a) is a sectional view showing the configuration of an embodiment of the present invention, and FIG. 2(b) is an embodiment of the invention. A partial cross-sectional view of the embodiment,
FIG. 2(C) is a top plan view of a freeze predictor according to an embodiment of the present invention, and FIG. 3 is a sectional view showing an example of the configuration of a piezoelectric vibrator according to the present invention. Figure 4 (a) to (C)
are attached diagrams showing the resonance layer properties of the piezoelectric vibrator, and as the freezing of the freezing liquid progresses, (a), (b),
It changes in the order of (C). In the figure, (1) is a piezoelectric vibrator, (2) is a thermally conductive container, (4) is a heat radiation fin, (5) is a liquid supply and drainage pipe, and (
3) is a space filled with a freezing liquid. Note that the same reference numerals in Figure 1 indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A thermally conductive container filled with a freezing liquid that contacts the liquid supply and drainage pipe and transmits the temperature of the liquid supply and drainage pipe, and is installed in this thermally conductive container and applies vibration to the freezing liquid in the container. A freeze predictor equipped with a piezoelectric vibrator that detects freezing conditions in freezing liquids based on changes in transmission resonance characteristics. (2) The freeze predictor according to claim 1, wherein the thermally conductive container is provided with radiation fins.