WO2010035983A2

WO2010035983A2 - Defrosting timing sensing device for an evaporator for a refrigerating cycle

Info

Publication number: WO2010035983A2
Application number: PCT/KR2009/005251
Authority: WO
Inventors: 진금수
Original assignee: Jin Kum-Soo
Priority date: 2008-09-26
Filing date: 2009-09-16
Publication date: 2010-04-01
Also published as: WO2010035983A3; KR20100035315A

Abstract

The present invention relates to a defrosting timing sensing device for an evaporator for a refrigerating cycle, and more particularly, to a device for sensing the defrosting timing of the frost formed at an outdoor heat exchanger for a heat pump system or at a unit type evaporator for a freezer, in which the device is simple in structure and excellent in sensing the defrosting timing, and setting of the defrosting timing is easily changed. The defrosting timing sensing device of the present invention comprises: a housing (10) installed in a casing (41) of an evaporator (40); an outdoor air suction means (14) constituted by installing a rotary shaft (16) in the housing and installing a suction fan (17) outside the rotary shaft (16); and a rotational frequency sensor (20) arranged in the housing (10) to sense the rotational frequency of the rotary shaft (16).

Description

Defrost timing detector for evaporator for refrigeration cycle

The present invention relates to a defrost time detector of an evaporator for a refrigeration cycle, and more particularly to a defrost time detector of frost formed on an outdoor heat exchanger for a heat pump system or a unit evaporator for a freezer.

As is well known, a unit type evaporator for an outdoor heat exchanger or a freezer that functions as an evaporator in a heat pump system performs an evaporation function of a refrigerant liquid expanded in an expansion valve, and the external air source evaporator 40 of the evaporator is typically As shown in FIG. 3, an air inlet 42 is formed at one side of the casing 41, and an air outlet 43 is installed at the other side of the fan 44, and the air inlet 42 of the casing 41 is formed. In the heat exchanger 45, a fin and tube type heat exchanger is usually installed, and when the refrigerant liquid is evaporated while passing through the heat exchanger tube of the heat exchanger, the fan 43 is driven to suck the outside air between the fins. Is evaporating.

When the evaporator evaporates the refrigerant liquid, if the air in the outside air or the freezing (refrigeration) room drops below the dew point temperature, frost starts to form on the surface of the heat pipe and the fin, and as time passes, the gap between the fins becomes narrower and becomes clogged. In this case, when the gap between the fins is blocked as described above, defrosting operation is performed to prevent the heat transfer performance and thus lower the evaporation efficiency of the refrigerant liquid.

On the other hand, the defrosting means is well known for the reverse cycle operation (acting the evaporator as a condenser), the melting of frost by the electrothermal heater, etc. Also, the defrosting means is equipped with a timer to control the defrosting at regular intervals, It is well known to control the defrosting means by measuring the thickness (quantity) of the gas in a predetermined value or more, but the control means conforms to various weather conditions at the place where the evaporator is installed and / or the optical narrowness of the heat exchanger structure, in particular the spacing between fins. The control was difficult.

Patent Document 1 discloses a wind pressure defrosting time detection device for a forced-air evaporative heat exchanger for a cooling and heating device for correcting the above-described problems. It is provided in the casing of the evaporation heat exchanger and has a differential pressure operation switch for detecting the load when the fan is applied to start the defrost operation, the differential pressure operation switch and the switch body for connecting the inside and outside of the casing, and the inside of the switch body A limit switch installed at the control panel and controlling a defrosting operation time point, a wind pressure differential operation plate connected to the limit switch and operating (connecting) the limit switch by air sucked into the switch body, and outside the switch body. Consists of the installed heating heater, the frost is formed between the fins of the evaporating heat exchanger flows into the casing. When the air amount is decreased to one to the fan load to a jam (the negative pressure generated in the casing by the casing and out of the pressure differential formed) air pressure difference operating plate starts the defrosting operation by connecting the limit switch.

Patent Document 1; KR 10-0674180 (B1)

However, in the above-mentioned pressure detection defrost point detection apparatus of the forced blow-type evaporative heat exchanger of Patent Document 1, first, the cost is increased due to the complicated structure, and second, the one side of the wind pressure operation plate is connected to the limit switch (hinge coupling). Since when the negative pressure is formed in the casing, the wind pressure operating plate only performs the arcing motion on the opposite side of the hinge coupling portion, so that the distance between the wind pressure operating plate and the switch body is changed depending on the magnitude of the negative pressure. Since the air intake amount is small, the fixed pressure is fixed, and if the negative pressure is delayed, the load of the fan cannot be solved, causing problems such as failure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a defrosting timing detector for a refrigerating cycle evaporator which corrects the above problems, simplifies the structure, satisfactorily detects the defrosting timing, and also allows the setting of the defrosting time to be simply varied. do.

In order to achieve the above object, the present invention is a housing installed in the casing of the evaporator; External air suction means for installing a rotating shaft in the housing and installing a suction fan outside the rotating shaft; It is made of a rotational speed sensor installed inside the housing to detect the rotational speed of the rotating shaft

As described above, the present invention consists of only the housing, the outside air suction means, and the rotational speed sensor, thereby simplifying the structure, reducing the cost, and ensuring reliability by not causing trouble.

When the rotating shaft is rotated in proportion to the pressure difference between the inside and the outside of the casing, the rotation speed is sensed, and when the rotation speed is higher than the set rotation speed, the defrosting operation can be performed to improve the defrosting of the evaporator. In this case, the defrosting operation can be easily performed, and the defrosting operation can be performed according to the external weather conditions and / or the wide gap between the fins, so that good defrosting can be performed.

1 is a cross-sectional view of an embodiment of the present invention.

2 is a side view of an embodiment of the present invention

Figure 3 is an illustration of an installation state of the embodiment of the present invention

1 is a cross-sectional view of an embodiment of the present invention, Figure 2 is a side view of an embodiment of the present invention, Figure 3 is an illustration of an installation state of an embodiment of the present invention, the present invention is a housing 10, the outside air intake means 14 And the rotation speed sensor 20.

The housing 10 is formed in a cylindrical shape of a predetermined length to form a flange 11 on one side thereof to be fixed as a fastener to the casing 41 of the evaporator 40, the fixing position is the interior of the casing 41 and the The communication surface is not limited, and the housing 10 is preferably injection molded together with the supporting

pieces

15a and 15b to be described later.

The external air suction means 14 forms the

support pieces

15a and 15b at regular intervals in the housing 10 to install the rotation shaft 16, and the suction fan 17 to the outside of the rotation shaft 10. ), The suction fan 17 is installed to be located inside the outer end of the housing 10 so as to quickly suck the outside air when a negative pressure is formed in the casing 41.

The rotation speed sensor 20 uses a well-known one, and is installed on the inner surface of the housing 10 to sense the rotation speed of the rotation shaft 15.

The rotation speed detection value of the rotation shaft 16 detected by the rotation speed sensor 20 is input to a control unit of a programmable logic controller (PLC) controlling a heat pump system or a refrigerator, and the input value is equal to or greater than a set value of a set program. When the defrosting means is driven (operated), and below the set value, the defrosting means is stopped.

On the other hand, in the present invention, if the defrost time is increased or shortened in an external weather condition, for example, in an area of high humidity or low humidity, or the defrost time is changed by a wide range of intervals between fins of the heat exchanger, it is easy to change only the set program of the controller. It can be adjusted.

The defrosting means may be any of well-known reverse cycle operation, a heat transfer heater, or a defrosting means of Patent No. 402366 to which the inventor has patented a heat pump system.

Reference numeral 42 denotes an air inlet, 43 an air outlet, 44 a fan, and 45 a heat exchanger.

In the present invention as described above, when the frost is formed on the surface of the heat exchanger 45, in particular, the fin during operation of the refrigeration cycle, negative pressure is formed in the casing 40 because the outside air is not sucked by the fan 44. The negative pressure is increased proportionally as the amount of frost is increased. When the negative pressure is formed in the casing 41 as described above, a pressure difference is generated between the negative pressure and the outside of the casing 4.

When the pressure difference occurs between the inside and the outside of the casing 40 as described above, as the suction fan 17 rotates while the outside air flows into the casing 40 through the housing 10, the rotating shaft 16 is rotated and the number of rotations thereof is also increased. The increase and decrease in proportion to the pressure difference, the rotation speed sensor 20 detects the rotation speed of the rotary shaft 16 and inputs the detected value to the controller of the PLC.

As described above, when the rotation speed of the rotation shaft 16 is input to the controller, the detected value is greater than or equal to a set value (for example, 100 RPM) [This set value is the magnitude of the negative pressure in the casing 41, that is, the frost formed on the surface of the heat exchanger 45. Heat transfer efficiency decreases as the amount increases, and the evaporation efficiency of the evaporator 40 decreases as the heat transfer efficiency decreases, and the design coefficient is set based on when the coefficient of performance of the refrigeration cycle falls below a certain amount. When the controller outputs to the solenoid-type 4-way valve, electrothermal heater switch, brine circulation pump, etc., which drive the defrosting means, the defrost means defrosted on the surface of the heat exchanger by driving the defrosting means. As the number of revolutions decreases and the number of revolutions of the rotating shaft 16 decreases as the negative pressure decreases, the detection value decreases and the defrosting operation ends.

Claims

A housing installed in the casing of the evaporator; External air suction means for installing a rotating shaft in the housing and installing a suction fan outside the rotating shaft; Defrost timing detector of the evaporator for a refrigeration cycle consisting of a rotation speed sensor installed inside the housing to detect the rotation speed of the rotating shaft
The defrost timing detector of an evaporator for a refrigeration cycle according to claim 1, wherein the casing is injection molded together with the support piece.
The defrost timing detector of the evaporator for a refrigeration cycle according to claim 1, wherein the suction fan is installed to be located inside the outer end of the housing.
The defrost timing detector of the evaporator for a refrigeration cycle according to claim 1, wherein the rotation speed sensor inputs the detected value to the controller and performs defrosting operation when the input value is equal to or higher than a set value of a set program.
5. The defrost timing detector of the evaporator for a refrigeration cycle, according to claim 4, wherein the set point is variable.