Temperature difference type defrosting control device suitable for air cooler

Abstract

The utility model discloses a temperature difference type defrosting control device suitable for an air cooler. The temperature difference type defrosting control device comprises a PLC. The metal guide rods are arranged between two adjacent air cooler coils of the air cooler fins; and a plurality of temperature probes. The plurality of temperature probes are respectively used for detecting the temperature of air, the temperature of the metal guide rod and the temperature of the corresponding air cooler coil pipe in real time and transmitting detected temperature signals to the PLC. According to the control device disclosed by the utility model, the frosting thickness is judged by detecting the temperature difference change among the detection points through the plurality of temperature probes, so that adverse effects on defrosting of the air cooler caused by too early or too late are avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of defrosting control of various cold air machines in high and low temperature refrigeration and freezing processing, and in particular to a temperature difference defrosting control device suitable for cold air machines. Background Art

[0002] When the air cooler in the cold storage is running, the outer surface temperature of the coil or fin is lower than 0℃. During the refrigeration process, the air cooler absorbs heat to reduce the ambient temperature, and at the same time, the water vapor in the ambient air is precipitated and attached to the surface of the air cooler heat exchanger to form a frost layer. The thickness of the frost layer gradually increases with the running time, resulting in a decrease in the heat transfer efficiency of the air cooler. Therefore, the air cooler with a certain thickness of frost must be defrosted. At the same time, regularly heating the air cooler to defrost it is also conducive to the easier discharge of the lubricating oil accumulated in the coil, so as to further improve the heat exchange efficiency of the air cooler.

[0003] At present, the most commonly used method in refrigeration systems is to use a pre-set defrost cycle and defrost time. That is, when the defrost cycle is reached, the control system is triggered to automatically enter the defrost program or send a defrost request signal to prompt manual start, and defrost is completed within the preset defrost time.

[0004] However, in the actual operation of cold storage, there are great differences in ambient temperature and relative humidity every day of the year, in different time periods of each day, such as winter and summer, sunny days, cloudy days and rainy days, day and night; even in the same cold storage, the types of goods stored, packaging forms, enterprise production and operation modes, and refrigeration system management and maintenance modes are not static. For example, some goods are well packaged, while others are damaged or even exposed; some goods have a high moisture content, while others have a very low moisture content; some incoming goods have a high temperature, while others have a low temperature; some goods are brought in and out during the day, while others are brought in and out at night; there is a period of time when the door is frequently opened for goods to be brought in and out, and sometimes the door is not opened once for several days. Various situations, such as these, will cause the speed of frosting of the air cooler to vary greatly. If a stereotyped and fixed defrosting cycle is used to control the defrosting of the air cooler, it is obviously too simple and crude, and it has great disadvantages:

[0005] First: The frost layer of the air cooler is very thick and defrosting cannot be started in time when defrosting is needed. The accumulation of too thick frost layer not only reduces the heat transfer coefficient and increases the resistance of air flowing through the fins of the air cooler, but in severe cases, the frost layer is too thick to block the fins and prevent air circulation, causing the performance of the air cooler to drop sharply or even fail to cool, increasing the energy consumption of the refrigeration system. Experiments show that when the average frost thickness of the air cooler is 2mm, the cooling capacity of the air cooler is only 1 / 3 of that when there is no frost or little frost. It is obvious that the excessively thick frost layer will seriously reduce the heat exchange efficiency of the air cooler.

[0006] Second: In some cases, the frost on the air cooler is too thick during the same defrost cycle, and the defrost is performed at a fixed defrost power and time, resulting in the frost layer not being completely melted, and the defrost is incomplete; when the next defrost is performed, the frost layer will be thicker than normal and will not be completely melted, thus forming a vicious cycle, with more frost remaining on the fins after each defrost than the previous one. This is increasingly detrimental to the heat exchange efficiency of the air cooler, and eventually the frost layer on the air cooler is too thick and cannot be cooled.

[0007] Third: Defrosting the air cooler before the frost layer reaches a certain thickness. Although excessively frequent defrosting improves the heat exchange efficiency of the air cooler, the defrosting process itself also consumes a certain amount of heat or electricity, especially electric defrosting. In addition to the heat consumed by melting the frost layer during defrosting, another part of the heat will also be lost or radiated to the surrounding environment, the air cooler body and the pipeline (taking a -20℃ cold storage as an example, the heat loss of ordinary air coolers during defrosting is about 40%); at the same time, defrosting and refrigeration are carried out alternately, and the air cooler and pipelines are often converted from cold to hot, which is obviously not conducive to energy saving.

[0008] Therefore, if the frost thickness of the air cooler can be monitored in real time and defrosted, the above-mentioned disadvantages can be avoided.

[0009] Based on the above technical problems, technicians in this field urgently need to develop a temperature difference defrost control device suitable for air coolers. Utility Model Content

[0010] The purpose of the utility model is to provide a temperature difference defrost control device suitable for an air cooler, which uses multiple temperature probes to detect the temperature difference changes between detection points to determine the thickness of frost, so as to avoid the adverse effects of defrosting the air cooler too early or too late.

[0011] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0012] The utility model discloses a temperature difference defrost control device suitable for a cold air blower, the defrost control device comprising:

[0013] PLC controller;

[0014] A metal guide rod arranged between two adjacent air cooler coils of the air cooler fins; and

[0015] Multiple temperature probes;

[0016] The plurality of temperature probes are used to respectively detect the temperature of the air, the metal guide rod and the corresponding air cooler coil in real time, and transmit the detected temperature signal to the PLC controller.

[0017] Furthermore, the PLC controller is used to receive temperature signals transmitted by a plurality of temperature probes, and to output a defrost signal according to the calculated temperature difference value.

[0018] Furthermore, the metal guide rod comprises:

[0019] A metal guide rod extension portion and a metal guide rod bending portion;

[0020] The metal guide rod extension portion extends along one side of two adjacent air cooler coils and is close to the side surfaces of the two air cooler coils;

[0021] The bent portion of the metal guide rod is bent and extended along the outer peripheral side of the corresponding air cooler coil and is abutted against the outer side surface of the corresponding air cooler coil.

[0022] Furthermore, the cross-section of the metal guide rod is square.

[0023] Furthermore, the plurality of temperature probes are respectively:

[0024] The air temperature detection temperature probe detects the air temperature in real time. a ;

[0025] The metal guide rod temperature detection temperature probe detects the temperature t at the center of the metal guide rod in real time. p ;

[0026] The first cooling air coil temperature detection temperature probe and the second cooling air coil temperature detection temperature probe are used to detect the temperature of one of the cooling air coils. e1 The second air cooler coil temperature detection probe is used to detect the temperature of another air cooler coil. e2 .

[0027] In the above technical solution, the utility model provides a temperature difference defrost control device suitable for a cold air blower, which has the following beneficial effects:

[0028] The control device of the utility model utilizes a plurality of temperature probes to detect the temperature difference change between the detection points to judge the thickness of the frost, so as to avoid the adverse effect of defrosting the cold air machine too early or too late. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. It is obvious that the drawings described below are only some embodiments recorded in the present utility model. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0030] Figure 1 The present invention is a schematic structural diagram of a temperature difference defrost control device suitable for a cold air blower disclosed in an embodiment of the present utility model.

[0031] Description of reference numerals:

[0032] 10. Air cooler fins; 11. Air cooler coils;

[0033] 1. PLC controller; 2. Metal guide rod; 3. Air temperature detection temperature probe; 4. Metal guide rod temperature detection temperature probe; 5. First air cooler coil temperature detection temperature probe; 6. Second air cooler coil temperature detection temperature probe. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0035] See also Figure 1 As shown;

[0036] A temperature difference defrost control device applicable to a cold air machine in this embodiment includes:

[0037] PLC controller 1;

[0038] A metal guide rod 2 arranged between two adjacent air cooler coils 11 of the air cooler fin 10; and

[0039] Multiple temperature probes;

[0040] The multiple temperature probes are used to respectively detect the temperatures of the air, the metal guide rod and the corresponding air cooler coil 11 in real time, and transmit the detected temperature signals to the PLC controller 1 .

[0041] Specifically, this embodiment discloses a temperature difference defrost control device, which uses a PLC controller 1 as a multi-point temperature input switch quantity and a defrost signal output; at the same time, two adjacent cold air machine coils 11 are selected on the cold air machine fins 10 of the cold air machine, and are connected in series using a metal guide rod 2, which is mainly used for heat conduction or cold conduction. At least four temperature probes are configured to detect the temperature of the air, the metal guide rod 2, and the two cold air machine coils 11 respectively, and finally determine whether to output the defrost signal based on the temperature signal and the temperature difference value.

[0042] Preferably, the PLC controller 1 of this embodiment is used to receive temperature signals transmitted by multiple temperature probes, and to output a defrost signal according to the calculated temperature difference value.

[0043] Preferably, the metal guide rod 2 of this embodiment includes a metal guide rod extension portion and a metal guide rod bending portion;

[0044] The metal guide rod extension portion extends along one side of two adjacent air cooler coils 11 and is close to the side surfaces of the two air cooler coils 11;

[0045] The bent portion of the metal guide rod is bent and extended along the outer circumference of the corresponding air cooler coil 11 and is in contact with the outer side surface of the corresponding air cooler coil 11 .

[0046] The present embodiment is only further explained and illustrated by a metal guide rod 2 in a structural form that can realize the series connection of two adjacent air cooler coils 11 for heat conduction or cooling. The metal guide rod 2 of the present embodiment is made of a metal material with good thermal conductivity and good corrosion and oxidation resistance, and the shape is not limited to the limitations of the present application, as long as the heat conduction or cooling of the two air cooler coils 11 can be achieved.

[0047] In order to better contact with the outer wall of the cooling air coil 11, the cross-section of the metal guide rod 2 in this embodiment is square.

[0048] The multiple temperature probes in this embodiment are:

[0049] Air temperature detection temperature probe 3, air temperature detection temperature probe 3 real-time detection of air temperature t a ;

[0050] The temperature probe 4 for detecting the temperature of the metal guide rod detects the temperature tp at the center point of the metal guide rod in real time;

[0051] The first air cooling coil temperature detection temperature probe 5 and the second air cooling coil temperature detection temperature probe 6, the first air cooling coil temperature detection temperature probe 5 is used to detect the temperature te1 of one of the air cooling coils 11, and the second air cooling coil temperature detection temperature probe 6 is used to detect the temperature te2 of the other air cooling coil 11.

[0052] The temperature probe and wire of this embodiment need to ensure that they do not affect the airflow. Therefore, the smaller the size of the temperature probe, the better, and the thinner the wire, the better. The temperature probe of this embodiment can be a thermocouple, a thermistor temperature probe, a thermal resistor temperature probe, etc., and the position of the temperature probe in this embodiment is only an exemplary description and can be adjusted according to actual design requirements and appropriately adjusted according to the type of air cooler.

[0053] When the air cooler has no frost layer, the temperature probe at the midpoint of the metal guide rod 2 is completely exposed to the air. p Close to a , that is, t a With t p The difference is the smallest, then also the smallest;

[0054] After the air cooler has been running for a period of time, the air cooler coil 11, the air cooler fins 10 and the metal guide rod 2 will have a certain thickness of frost. Since the frost layer acts as a heat insulation, at this time t a With t p The difference increases gradually, The thicker the frost, the larger the a With t p The larger the difference, the The larger the value, the larger the PLC controller is. a ,t e By making certain correction calculations based on the value change, the thickness of the frost layer can be basically determined, a defrost signal can be issued, and the refrigeration system will defrost the air cooler.

[0055] The defrost control device of the utility model can more accurately judge the required defrost cycle and can perform defrost in time; it avoids various disadvantages brought by the traditional pre-set defrost cycle and is an energy-saving device. The defrost control device of the utility model can be used to add air coolers to existing projects, and can also be used in projects provided in conjunction with new equipment.

[0056] In the above technical solution, the utility model provides a temperature difference defrost control device suitable for a cold air blower, which has the following beneficial effects:

[0057] The control device of the utility model utilizes a plurality of temperature probes to detect the temperature difference change between the detection points to judge the thickness of the frost, so as to avoid the adverse effect of defrosting the cold air machine too early or too late.

[0058] The above only describes some exemplary embodiments of the present invention by way of illustration. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A temperature difference defrost control device suitable for a cold air blower, characterized in that: The defrost control device comprises: PLC controller (1); A metal guide rod (2) arranged between two adjacent air cooler coils (11) of an air cooler fin (10); and Multiple temperature probes; The plurality of temperature probes are used to respectively detect the temperature of the air, the metal guide rod and the corresponding air cooler coil (11) in real time, and transmit the detected temperature signals to the PLC controller (1).

2. A temperature difference defrost control device suitable for a cold air blower according to claim 1, characterized in that: The PLC controller (1) is used for receiving temperature signals transmitted by a plurality of temperature probes, and for outputting a defrosting signal according to a calculated temperature difference value.

3. A temperature difference defrost control device suitable for a cold air blower according to claim 1, characterized in that: The metal guide rod (2) comprises: A metal guide rod extension portion and a metal guide rod bending portion; The metal guide rod extension portion extends along one side of two adjacent cooling air coils (11) and is close to the side surfaces of the two cooling air coils (11); The bent portion of the metal guide rod is bent and extended along the outer peripheral side of the corresponding air cooler coil (11) and is in contact with the outer side surface of the corresponding air cooler coil (11).

4. A temperature difference defrost control device suitable for a cold air blower according to claim 3, characterized in that: The cross-sectional shape of the metal guide rod (2) is square.

5. The temperature difference defrost control device suitable for a cold air blower according to claim 3, characterized in that: The multiple temperature probes are: The air temperature detection temperature probe (3) detects the air temperature t in real time. a ; The metal guide rod temperature detection temperature probe (4) detects the temperature t at the center point of the metal guide rod in real time. p ; A first cooling air coil temperature detection temperature probe (5) and a second cooling air coil temperature detection temperature probe (6), wherein the first cooling air coil temperature detection temperature probe (5) is used to detect the temperature t of one of the cooling air coils (11). e1 The second cooling air coil temperature detection probe (6) is used to detect the temperature t of another cooling air coil (11). e2 .

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