JPH0610314Y2 - Frost detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a frost detection device.

(Prior Art) As a conventional example of the frost detection device, for example, Japanese Patent Laid-Open No. 57-12329
The frost sensor described in the publication can be mentioned. FIG. 8 shows a schematic configuration diagram of the device. In FIG.
Reference numeral 0 denotes a magnetostrictive ribbon made of FeNiSiB type amorphous material. One end of the magnetostrictive ribbon 30 adhered to the support frame 31 has an elastic wave exciting coil 32 for inducing an elastic wave in the magnetostrictive ribbon 30 and the other end. Elastic wave detection coils 33 that output signals according to the amount of propagation of the induced elastic waves are provided on the side. The coils 32,
When frost adheres to the magnetostrictive ribbons 30 between the regions 33, the amount of propagation loss of the elastic wave increases, which is detected by the elastic wave detecting coil 33 to determine the presence or absence of frost. ing.

By the way, the frost formation detecting member composed of the magnetostrictive ribbon 30 may be composed of a wire-shaped metal amorphous material. In this case, the device is downsized, the operating power is reduced, and the detection sensitivity is improved. Can be achieved. Such a device is attached to, for example, an outdoor heat exchanger arranged in the outdoor unit of an air conditioner, and detects and removes when a predetermined amount of frost adheres and grows on the outdoor heat exchanger during heating operation. It can be used to switch to frost operation. FIG. 9 shows the main configuration of such an apparatus. In FIG. 9, 41 is a frost detection member made of the above amorphous wire, and 42 and 43 are end portions of the frost detection member 10. An elastic wave excitation coil and an elastic wave detection coil are provided. In this case, a frosting surface 44 where frost growth similar to that of the outdoor heat exchanger occurs is formed at a position facing the frosting detecting member 41.
The separation distance between the frost formation detection member 41 and the frost formation detection member 41 is set according to the frost formation amount required to switch to the defrosting operation. Therefore, during the heating operation, the frost that has grown from the frosting surface 44 reaches the frosting detection member 41 and exerts a mechanical restraining force on the frosting detection member 41. Therefore, the detection level in the elastic wave detection coil 43 is increased. When the temperature drops, the defrosting operation is switched to.

In FIG. 10, the frost formation detecting member 45 is composed of a thin diaphragm, and piezoelectric elements 46 and 47 are attached to both ends of the frost formation detecting member 45 to detect the frost formation. The schematic diagram is shown. When the signal of the resonance frequency of the frost formation detecting member 45 is input to the one piezoelectric element 46, when the frost growing from the frost formation surface 48 reaches the frost forming detection member 45, the resonance point is Since it changes, the detection level of the other piezoelectric element 47 lowers, and frost formation is detected accordingly. As shown in FIG. 11, the device configuration for detecting frost formation based on such a change in vibration characteristics is a cantilevered configuration of the frost formation detection member 45, and piezoelectric elements 46, 47 are provided on the upper and lower surfaces on the base end side. It is also possible to attach each.

(Problems to be solved by the invention) By the way, when the defrosting operation is performed based on the detection signal from the frost detection device as described above, for example, in an air conditioner, it adheres to the outdoor heat exchanger and the frost detection device. The frost is dissolved and the dissolved water flows downward due to its own weight. Therefore, in general, the frost formation detecting device is mounted on the outdoor heat exchanger with its frost formation surface positioned vertically, and the dissolved water flows down along this frost formation surface promptly, The smaller the particle size, the greater the interface adsorption force from the frosted surface with respect to its own weight, and the slower the flow rate along the frosted surface becomes. Particularly, in the frost formation detecting device as described above, the separation distance between the frost formation surface and the frost formation detection member arranged to face the frost formation surface is set to be relatively small, so that the frost formation surface is formed. Even if the water droplets have a small particle diameter, they easily come into contact with the frost formation detecting member and are likely to become so-called bridge-shaped water droplets. In such a bridge-shaped water droplet, the interface suction force acts also from the frost detection member side, so that the flow-down speed becomes slower. As a result, there is a problem that the heating operation is likely to be restarted before the small water droplets on the frosted surface are not completely removed, and a malfunction is likely to occur due to such residual water. In other words, the residual water as described above freezes after heating operation is restarted and before a new frost is formed, exerting a mechanical restraining force on the frost detection member. This is because the amount increases and the vibration characteristics change.

The present invention has been made in view of the above, and an object thereof is to provide a frost formation detecting device capable of reducing malfunction caused by residual water after defrosting.

(Means for Solving the Problem) Therefore, in the frost formation detecting device of the present invention, the frame 5 is provided with the frost formation surface 8 extending in the vertical direction, and the frost formation detection member is opposed to the frost formation surface 8 and is substantially parallel to the frost formation surface. In the frost formation detecting device in which 9 are provided, the frost formation surface 8 is formed with a plurality of recessed grooves 21 intersecting the flow direction of water droplets along the frost formation surface 8.

(Operation) In the above-mentioned frost formation detecting device, the water droplets having a small particle size generated on the frost formation surface 8 flow into the recessed groove 21 on the way to the lower end of the frost formation surface 8. Then, in this recessed groove 21,
Similarly, it merges with other small droplets that have flowed into the recessed groove 21. Then, when it overflows from the recessed groove 21, it becomes a water droplet having a larger particle diameter and flows down. Therefore, as compared with the conventional case where the small droplets are allowed to flow down to the lower end on the frosted surface, the droplets are increased in size in each of the recessed grooves 21 in the above, so that the flow-down speed is increased, It will be discharged from the lower end of the frosted surface 8 in a shorter time. As a result, it becomes possible to reduce the water droplets remaining on the frosted surface 8, and the malfunction caused by the residual water after defrosting is reduced.

(Embodiment) Next, a concrete embodiment of the frost formation detecting apparatus of the present invention will be described in detail with reference to the drawings.

First, FIG. 3 schematically shows the outdoor heat exchanger 1 arranged in the outdoor unit of the air conditioner. This outdoor heat exchanger 1 is configured by arranging a large number of thin plate-shaped fins 2 ... In parallel with each other and inserting a refrigerant pipe 3 into these fins 2. Then, as shown in the figure, the frost detection device 4 according to one embodiment of the present invention is attached between the fins 2 and 2 located near the central portion.

FIG. 4 is a view taken along the line IV-IV in FIG. 3, and in FIG. 4, reference numeral 5 denotes a flat frame of the frost detection device 4, which is a rear end side (in the drawing) of the frame 5. Arc-shaped cutouts 6, 6 are formed along the outer peripheral surfaces of the refrigerant pipes 3, 3 at the upper and lower corners (on the left end side), respectively, and the upper and lower edges are respectively extended to the rear end side. The extending leaf springs 7, 7 are fixed, and when the refrigerant pipes 3, 3 are positioned so as to fit into the notches 6, 6, the notches 6, 6 in the refrigerant pipes 3, 3 are formed. The leaf springs 7, 7 are in contact with the refrigerant pipes 3, 3 at a position opposite to the contact portion position of the above, so that the frame 5 is fixedly attached to the refrigerant pipes 3, 3. On the other hand, on the front end side of the frame 5 (on the right end side in the figure), a frost surface 8 extending vertically at substantially the same position as the front edge of the fin 2 and parallel to each other with a predetermined distance from the frost surface 8. A frost formation detecting section including a wire-shaped frost formation detecting member 9 disposed in the above is formed. Next, the configuration of the frost formation detecting section will be described with reference to FIG.

As shown in FIG. 2, a U-shaped recess is formed at the front end of the frame 5, and the bottom surface of this recess, that is, the vertical surface, projects slightly toward the front end side in the central region thereof. A step portion is formed, and the vertical surface of this step portion is the frosted surface 8. On the other hand, the protrusions on the lower and upper front end sides of the recessed portion are coil supporting portions 11 and 12, respectively.
And each of these coil support portions 11,
Coil mounting holes 13 and 14 are drilled in 12 at coaxial positions in the vertical direction. An elastic wave exciting coil 15 is inserted in one of these coil mounting holes 13, and an elastic wave detecting coil 16 is inserted in the other 14 thereof. Each of these coils 15, 16 and the coil mounting hole 13,
An elastic body 17 made of, for example, silicon rubber is filled in the fitting gap between the coils 15 and 14, and the positions of the coils 15 and 16 are fixed. A frost formation detecting member 9 made of an Fe-based amorphous wire having a diameter of about 0.1 to 0.15 mm is stretched between the coils 15 and 16. This frost detection member 9
By inserting both ends thereof into the center through holes of the coil winding cores 18 and 19 of the coils 15 and 16, respectively, and filling the gaps in the center through holes with an elastic body such as silicon rubber. The mounting state is such that the propagation of elastic waves is not hindered.

Further, in the above, as shown in FIG. 1, the frosted surface 8 has a V-shaped recessed groove 21 that is continuous with the left and right edges of the frosted surface 8.
.. are formed in plurality, and the frosted surface 8 is divided into a plurality of vertical surfaces by the recessed grooves 21. The cross section of these recessed grooves 21 is V-shaped as shown in FIG.
More specifically, the upper surface and the lower surface forming the V-shape are both surfaces inclined from the frosted surface 8 downward in the recess direction. The upper end surface and the lower end surface of the stepped portion at the periphery of the frosted surface 8 are also formed by inclined surfaces similar to the above.

Next, the operating state of the frost formation detecting device having the above configuration will be described.

During heating operation in the air conditioner, by applying a high-frequency input signal to the elastic wave exciting coil 15, elastic waves are excited in the frost formation detecting member 9. This elastic wave propagates through the frost detection member 9 from the elastic wave exciting coil 15 side to the elastic wave detecting coil 16 side, whereby a high-frequency electric signal is induced in the elastic wave detecting coil 16, This signal level is compared with the reference level. When frost is formed on the outdoor heat exchanger as the heating operation is continued and grows, the same frost is generated and grown on the frosted surface 8 of the frost detection device. When the frost that has arrived reaches the frost formation detecting member 9, a mechanical restraining force is generated in the frost formation detecting member 9, so that the loss amount of the elastic wave propagating through the frost forming detection member 9 becomes large. The detection signal level at the elastic wave detecting coil 16 is lowered. When it is determined that the signal level has dropped below the reference level, a frost detection signal is output, whereby the heating operation is interrupted and switching to the defrosting operation is performed.

By this defrosting operation, the frost that has adhered and grown on the outdoor heat exchanger and the frost detection device gradually dissolves into water droplets, which are removed by falling by their own weight. And the heating operation is restarted at the time when the defrosting of the entire outdoor heat exchanger is completed, but conventionally, since small water droplets with a particle size remain on the frosted surface at this time, The frost detection operation after the heating was restarted was likely to cause a malfunction. However, in the above-described embodiment, since the frosted surface 8 is formed with a large number of recessed grooves 21 that intersect the flow direction of the water droplets, the above-described residual water droplets are reduced. That is, the water droplets having a small particle size generated on the frosted surface 8 immediately flow into the recessed groove 21 while flowing down to the lower end of the frosted surface 8 and flow into the recessed groove 21. Combine with other droplets that come. Then, when it overflows from the recessed groove 21, it becomes a water droplet having a larger particle diameter and flows down. Therefore, the flow-down speed is high, and the same phenomenon is repeated for each recessed groove 21. It is discharged from the lower end of the frosted surface 8 within a short time. As a result, the water droplets remaining on the frosted surface 8 are significantly reduced as compared with the conventional case. In particular, in the above-described embodiment, since the recessed groove 21 is formed in a V-shape, the water droplets flowing down from each recessed groove 21 mainly flow down along the side wall of the frosted surface 8. Therefore, the water droplets remaining on the frosted surface 8 are further reduced.

As a result of the above, even after the frost detection operation by the high frequency input to the elastic wave excitation coil 15 is restarted, it is possible to more accurately determine the newly growing frost amount without causing a malfunction. As a result, unnecessary switching to the defrosting operation is suppressed and the heating operation is maintained for a longer time, so that comfort during heating can be improved.

The specific embodiment of the present invention has been described above,
The above embodiment is not limited to this invention, and various modifications can be made within the scope of this invention. For example, in the above embodiment, the shape of the concave groove 21 on the frosted surface 8 is a V-shape. However, even in the case of forming a substantially horizontal straight line as shown in FIG. 5, for example, it is faster after the small droplets are combined in the concave groove 21 to form a large water droplet. It can be made to flow down at a speed. Further, as shown in FIG. 6, it is possible to obtain substantially the same effect as that of the above-described embodiment by constructing the shape inclining from one side edge to the other side edge. Further, as shown in FIG. 7, it is also possible to form the frosted surface 8 in a V shape, and in this case, water droplets are further collected at the apex of the V shape in the concave groove 21. As a result, the water droplets coalesce more quickly, so that the water droplets on the frosted surface 8 can be removed in a shorter time. Further, the cross-sectional shape of the recessed groove 21 may be other than the V-shaped cross section in the above-described embodiment. Further, in the above-described embodiment, an example in which the frost formation detecting member 9 is formed of an amorphous wire has been described, but a device forming the frost formation detecting member using the amorphous ribbon described above with reference to FIG.
The present invention can also be applied to the device in which the frost detection member is formed of the thin plate vibration plate shown in FIGS. 10 and 11.

(Effects of the Invention) As described above, in the frost detection device of the present invention, by providing the frosted surface with the concave groove, water droplets having a small particle size generated on the frosted surface flow down. On the way, it will flow into the recessed groove, coalesce with other small droplets, and will flow down as water droplets with a larger particle size, so the flow-down speed will be faster, and therefore within a short time. It is discharged from the lower end of the frosted surface. As a result, the number of water drops remaining on the frosted surface is reduced, and the malfunction caused by the residual water after defrosting is reduced.

[Brief description of drawings]

FIG. 1 is a front view of a frost detection device according to an embodiment of the present invention, FIG. 2 is a side view with a partial cross section of the frost detection device, and FIG. 3 is outdoor heat with the frost detection device attached. FIG. 4 is a schematic front view of the exchanger, FIG. 4 is a view taken along the line IV-IV in FIG. 3, and FIGS. 5 to 7 are views of the frosted surface of the frost detection device in another embodiment of the present invention. FIG. 8 is a front view showing a recessed groove shape, FIG. 8 is a perspective view of a conventional frost detection device, and FIGS. 9 to 11 are frost formations having different structures and methods from the conventional device shown in FIG. It is a principal part schematic diagram in a detection apparatus. 5 ... frame, 8 ... frost surface, 9 ... frost detection member,
21 ... Recessed groove.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-12329 (JP, A) Actual development S58-145477 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A frame (5) is provided with a frosting surface (8) extending in the vertical direction, and a frosting detecting member (9) is arranged substantially parallel to and facing the frosting surface (8). A frost formation detecting device comprising: a plurality of recessed grooves (21) formed on the frost formation surface (8) intersecting a water droplet flow direction along the frost formation surface (8). Frost detection device.