JP2000258001A - Refrigeration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration system provided with a temperature sensor for refrigerant evaporator in order to perform antifreeze control surely. SOLUTION: The refrigeration system comprises a sensor 3 disposed on the leeward side of a refrigerant evaporator 1 in order to measure the temperature of conditioned air and to stop operation of the refrigeration system when the measured temperature of conditioned air drops below a set level thus preventing the refrigerant evaporator 1 from freezing. Heat-sensitive part 31 of the antifreeze sensor 3 is arranged in a tubular clip 2 provided with a net 21 and cooling fins 12 are engaged with engaging pieces 23, 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus such as an air conditioner for a vehicle, and more particularly to a temperature sensor for performing anti-freezing control for removing frost adhering to a refrigerant evaporator.

[0002]

2. Description of the Related Art In an air conditioner for a vehicle, a temperature sensor for preventing freezing is attached to a leeward side of a refrigerant evaporator (evaporator) of a refrigerating device installed in an air conditioning duct. In the refrigerating device, the temperature of the conditioned air that has passed through the refrigerant evaporator serving as a heat exchanger is detected by the temperature sensor for preventing freezing,
For example, freeze prevention control is performed in which the operation of the refrigerating apparatus is stopped when the air temperature on the leeward side of the refrigerant evaporator is 3 ° C and the refrigerating apparatus is restarted at 4 ° C. This temperature sensor for preventing freezing is desirably mounted at the lowest temperature position in the refrigerant evaporator where frost is most likely to adhere.

The following precautions must be taken for the mounting position of the temperature sensor for preventing freezing. The temperature distribution of the conditioned air downstream of the refrigerant evaporator fluctuates due to a change in the flow rate of the refrigerant accompanying a change in the rotation speed of the compressor of the refrigeration apparatus. If the dimensions of the refrigerant evaporator are changed by changing the specifications of the air conditioner, a change in the refrigerant stagnation region occurs in which the refrigerant stagnates in the refrigerant evaporator when the operation of the refrigeration device is stopped. When the arrangement of the blower, the refrigerant evaporator, and the like is changed, the wind speed distribution on the leeward side of the refrigerant evaporator changes.

[0004]

Therefore, in order to mount the temperature sensor for preventing the freezing of the refrigerant evaporator at the optimum position in each type of vehicle air conditioner, it is necessary to carry out a test for each type and examine it. There is a need to. An object of the present invention is to provide a refrigeration apparatus provided with a temperature sensor of a refrigerant evaporator, which can accurately perform antifreezing control.

[0005]

Means for Solving the Problems (1) At a predetermined position of the refrigerant evaporator, a flow velocity reducing means for reducing the flow velocity of the conditioned air passing through the refrigerant evaporator is attached, and in a region where the flow velocity is reduced. The heat sensitive part of the temperature sensor for freezing prevention is arranged. The conditioned air in the portion where the flow velocity has decreased has a longer time in contact with the refrigerant evaporator and has a lower temperature than the surroundings having a normal flow velocity. Therefore, the anti-freezing temperature sensor can reliably detect the surface temperature of the refrigerant evaporator that is optimal for anti-freezing control. Further, it is not necessary to study the mounting position as described in the section of the problem to be solved by the invention.

In the position where the flow velocity is reduced, the flow velocity on the surface of the temperature sensor for preventing freezing is reduced, so that the sensitivity of the temperature sensor for detecting the temperature of the refrigerant is reduced. For this reason, there is a possibility that a delay may occur in the temperature detection when the refrigeration apparatus is restarted. For this reason, a flow velocity increasing means is provided near the flow velocity decreasing means, and a heat sensing part of the restart temperature sensor is provided at a position where the flow velocity has increased, so that the temperature required for the restart can be quickly detected. Therefore, there is no delay in restarting.

The flow rate reducing means is a cylindrical clip provided with an inflow port on the upstream side, an outflow port on the downstream side, and a ventilation resistance increasing mechanism such as a net or a throttle therein. It is fixed at a predetermined position. The temperature sensor for freezing prevention is attached so that the heat-sensitive part is located inside the cylindrical clip. For this reason, the conditioned air whose flow velocity has been reduced by a ventilation resistance increasing mechanism such as a net or a throttle has a longer contact time with the refrigerant evaporator and has a lower temperature than the surroundings having a normal flow velocity. . For this reason, the freezing prevention temperature sensor attached so that the heat sensitive part is located inside the cylindrical clip can reliably detect the surface temperature of the refrigerant evaporator that is optimal for the freezing prevention control.

The flow rate increasing means is a cylindrical clip provided with an inflow port on the upstream side, an outflow port on the downstream side, and a venturi inside, and the temperature sensor for restarting has a heat sensitive part in the venturi. Is attached to the cylindrical clip, and the cylindrical clip is fixed to a predetermined position of the refrigerant evaporator.

The above-mentioned flow rate increasing means is provided adjacent to the flow rate decreasing means, and a restart temperature sensor is provided at a position where the flow rate has increased, so that the temperature required for restart can be quickly detected. As a result, there is no delay in temperature detection when the refrigeration apparatus is restarted.

[0010] (Claim 5) The cylindrical clip and the cylindrical clip are made of resin integrally molded in parallel, and the temperature sensor for freezing prevention and the temperature sensor for restarting are provided with a heat sensitive portion in a row. Integrated temperature sensor. Therefore, the temperature sensor for preventing freezing and the temperature sensor for restart can be easily arranged at a predetermined position of the refrigerant evaporator.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a refrigerant evaporator 1 of a refrigerating apparatus installed in an air conditioning duct of an air conditioner mounted on an automobile and through which conditioned air passes, and the refrigerant evaporator 1 A cylindrical clip 2 which is attached to the leeward side of the vehicle and has a built-in flow rate reducing means 20 for reducing the flow rate of the conditioned air, and a temperature for freezing prevention for freezing control of a refrigerating cycle fixed to the cylindrical clip 2. 2 shows a sensor 3.

As shown in FIG. 2, in this embodiment, the refrigerant evaporator 1 has a large number of cooling pipes 1 arranged in parallel in the vertical direction.
A laminated evaporator in which cooling fins 12 are arranged between each of 1 and 11 is used. In the refrigerant evaporator 1, a liquid-phase refrigerant flows from an inlet 13 to an upper portion (upper side in the drawing) from a liquid tank, and a gas-phase refrigerant flows out from a lower portion (lower side in the drawing) to an compressor through an outlet 14.

The tubular clip 2 is integrally formed of a resin which is hardly deteriorated even at a low temperature, and has a rectangular tubular portion 22 having a net 21 as a flow velocity reducing means 20. In the present embodiment, the cylindrical clip 2 is disposed 10 mm above the lower end 121 of the cooling fin 12 for the following reason.

It is desirable to dispose it near the refrigerant outlet side of the refrigerant evaporator 1 in consideration of superheat which affects the cooling capacity (the closer to the lower end 121 of the cooling fin 12, the better). However, if it is less than 10 mm, condensed water may stay inside the cylindrical clip 2 made of resin, and freezing or corrosion may occur.

From above and below the cylindrical portion 22, engaging pieces 23, 23 extend forward (toward the refrigerant evaporator).
Corrugated irregularities 24, 24 that engage with the cooling fins 12 are provided on the outer surfaces of the cooling fins 3, 23.

A temperature sensor 3 for preventing freezing is inserted into the cylindrical portion 22 from the side. The heat-sensitive portion 31 of the temperature sensor 3 for preventing freezing is located at the center of the cross section of the cylindrical portion 22 and the air is supplied to the net 21 by the net 21. It is located in the area where the flow velocity is slow.

In the present embodiment (FIG. 1), the heat sensitive portion 31 is disposed downstream of the net 21, but the net 21 may be disposed upstream of the heat sensitive portion 31. Network 21, the flow rate a of the heat sensitive portion 31 is selected to be a <a _min to a minimum wind speed a _min throughout the heat exchange portion of the refrigerant evaporator 1. In this example, a wire having a diameter of 0.25 mm and a mesh of 30 was selected.

As shown in FIG. 5, the flow velocity reducing means may have another structure such as a diaphragm 25, a hole plate 26, a slit 27, etc., as shown in FIG. Further, the cylindrical portion 22 may be a square tube other than a square tube, a cylinder, or the like.

The cylindrical clip 2 includes upper and lower engaging pieces 23, 2
3 are cooling fins 12, 12 at predetermined positions of the refrigerant evaporator 1.
It is inserted and attached between. Cylindrical clip 2
It is preferable that the fin is fixed at a position higher by 10 mm from the cooling fin 12 which is the outlet side of the refrigerant where the heat exchange ends most in the operation of the normal refrigeration apparatus. This takes into account the superheat which affects the cooling capacity, and is close to the outside of the refrigerant passage of the refrigerant evaporator 1 and the cylindrical clip 2
This is because it is suitable for preventing condensed water from staying therein and causing freezing and corrosion.

In the configuration shown in FIG. 1, the flow rate of the airflow flowing through the cylindrical clip 2 and coming into contact with the heat-sensitive part 31 is low, so that the temperature sensor 3 for preventing freezing has low sensitivity to the temperature change of the airflow. When the temperature of the airflow flowing in the cylindrical clip 2 rises and the refrigeration cycle is restarted, this decrease in sensitivity is likely to cause a delay in the temperature detection of the freeze prevention temperature sensor 3 and a delay in restart timing.

In an embodiment according to a second aspect of the present invention, as shown in FIGS. 3 and 4, a cylindrical clip 4 is provided in parallel with the cylindrical clip 2 and a speed increasing means 40 is provided therein.
And a restart temperature sensor 5 formed integrally with the anti-freezing temperature sensor 3 in a region where the speed of the conditioned air is increased by the venturi 41.
Of the heat sensitive part 51 is arranged.

The restarting temperature sensor 5 is selected so that the flow velocity b of the portion where the heat-sensitive portion 51 is disposed is b> a _min with _respect to the minimum wind speed a _{min in the} entire heat exchange portion of the refrigerant evaporator 1. Thus, the restart temperature sensor 5 can quickly detect a rise in the temperature of the refrigerant evaporator 1 and can eliminate discomfort caused by a rise in the temperature of the cool air due to a delay in restart.

The restarting temperature sensor 5 integrated with the anti-freezing temperature sensor 3 as shown in the present embodiment is excellent in mountability. The temperature sensor 3 for preventing freezing and the temperature sensor 5 for restart may be separate and independent sensors. Also,
The venturi 41 shown in FIGS. 3 and 4 has a slit shape, but may have a circular orifice shape in cross section.

[Brief description of the drawings]

FIG. 1 is a perspective view showing assembling of a freeze prevention temperature sensor with a cylindrical clip.

FIG. 2 is a front view of a refrigerant evaporator.

FIG. 3 is a perspective view of a cylindrical clip provided with a restart temperature sensor.

FIG. 4 is a three-view drawing of a cylindrical clip provided with a restart temperature sensor.

FIG. 5 is a plan view of a flow velocity reducing unit according to another embodiment (a, b, c).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigerant evaporator 2 Cylindrical clip 3 Freezing prevention temperature sensor 4 Cylindrical clip 5 Restart temperature sensor 20 Flow rate reduction means 21 Net 25 Throttle 31 Heat sensitive part 40 Flow rate increasing means 41 Venturi 51 Heat sensitive part

Claims (5)

[Claims] 1. A refrigerant evaporator which is disposed downstream of a refrigerant evaporator and measures the temperature of conditioned air. When the measured conditioned air becomes lower than a set temperature, the operation of the refrigerating apparatus is stopped and the refrigerant evaporator is stopped. A refrigerating apparatus having a freezing prevention temperature sensor for preventing freezing, wherein a flow rate reducing means for reducing the flow rate of the conditioned air is provided at a predetermined position of the refrigerant evaporator; A refrigeration apparatus, further comprising a heat-sensitive portion of the temperature sensor for preventing freezing. 2. The refrigeration apparatus according to claim 1, further comprising a flow rate increasing means for increasing a flow rate of the conditioned air in proximity to said flow rate reducing means, wherein the conditioned air is supplied to a flow rate increasing area by said flow rate increasing means. A refrigeration system comprising a heat sensing part of a restart temperature sensor for restarting the refrigeration system when the temperature exceeds a predetermined temperature. 3. The refrigeration apparatus according to claim 1, wherein said flow rate reducing means has an inflow port on an upstream side, an outflow port on a downstream side, and a ventilation resistance increasing mechanism such as a net or a throttle provided therein. A mold clip, wherein the freeze prevention temperature sensor is mounted such that a heat-sensitive part is located inside the cylindrical clip, and the cylindrical clip is fixed to a predetermined position of the refrigerant evaporator. And refrigeration equipment. 4. The refrigerating apparatus according to claim 2, wherein the flow rate increasing means is a cylindrical clip provided with an inflow port on an upstream side, an outflow port on a downstream side, and a venturi therein. A refrigerating apparatus, wherein a temperature sensor is attached to the cylindrical clip so that a heat-sensitive part is located in the venturi, and the cylindrical clip is fixed to a predetermined position of the refrigerant evaporator. 5. The refrigeration apparatus according to claim 3, wherein the cylindrical clip and the cylindrical clip are made of resin integrally molded in parallel with each other, and the freeze prevention temperature sensor and the restarting are provided. What is a temperature sensor?
A refrigeration apparatus, wherein the refrigeration apparatus is an integrated temperature sensor in which heat-sensitive units are arranged.