Generally speaking, when buying a chiller, you will have questions. I don't know how to judge the chilled water flow rate of the chiller? From what aspects should the chiller water flow be considered? Here is a brief talk.

The detection of the return water temperature and the outlet water temperature of the chiller should be carried out in the normal state of the unit:

After 30 minutes of starting up, check the system or the chilled water system inlet and outlet thermometers through the unit's control system parameters, and the inlet and outlet water temperatures of the unit can be read when the unit is running. The difference must be about 4-6 degrees. If the temperature difference between the inlet and outlet water is too large, it means that the water flow of the water system through the plate is too small, which may cause the unit to fail to operate normally or be damaged.

Water pressure detection of the inlet and outlet pipes of the unit

Through the detection of the return water pressure and the outlet water pressure value, check the water flow rate of the chiller under the pressure difference between the inlet and outlet water pressures in the random manual of the unit. By referring to the water flow corresponding table or diagram of the unit in the manual, So as to judge whether the water system is normal; and through this difference to judge which section of the water pipeline has a large resistance value, and make corresponding rectification plans and actions.

Compressor copper pipe suction temperature detection only needs to be carried out during refrigeration operation

If it is detected that the suction temperature of the compressor is lower than 0 degrees after the refrigeration chiller is turned on for 30 minutes, it means that the water flow in the water-side heat exchanger is not enough, which causes the evaporation temperature and the evaporation pressure to drop, and causes the Freon to flow in the evaporator. The suction pipe of the compressor is still evaporating and absorbing heat, which will cause the suction temperature of the compressor to be lower than 0 degrees; in addition, it is necessary to exclude the drop in evaporating pressure and evaporating temperature caused by the too low water temperature set point; The low water temperature unit can be considered normal as long as the compressor has a suction superheat of 6～8℃. Therefore, under normal water flow, the suction temperature of the compressor will generally be greater than 0°C, and water system problems should be eliminated if it is lower than this value.

The current needs to be detected when the pump is running

By detecting the running current of the chiller water pump and comparing it with the rated current, it can be judged whether the actual water flow is larger or smaller than the rated water flow of the pump. A comprehensive judgment can be made with the previous parameters to obtain an accurate water system detection analysis and judgment. Report.

The water selection pump is generally centrifugal, so it is a problem to determine its flow and head.

Determination of pump flow:

We can calculate the energy balance of the chiller as a system. The heat entering the system includes: the cooling capacity plus the motor power, the heat removed from the system, the heat carried by the cooling water and the heat dissipated in the environment, and the heat transferred to the environment is omitted. According to the process requirements (inlet water temperature and outlet water temperature), the flow of circulating water can be obtained. For example, the total maximum cooling capacity of a centrifugal refrigerator and a screw refrigerator is 2637+1231=3947kw, The motor power is: 467+256=723kw, and the total heat (cold) generated by 4670kw needs to be removed. If the cooling water passes through the cooling tower to change from 37°C to 32°C according to the design requirements, the amount of heat it brings out is The water volume should be: 4670÷1.163×1000÷(37-32)=803.1m3/h

, (1.163 is the conversion coefficient between kilowatts and kcal), so that the flow rate of the pump should be determined, generally consider two pumps operation, one pump standby mode, in order to facilitate operation in the high temperature period.

The second is the pump head. It should calculate the resistance loss based on the flow rate of the water in the pipeline (determined by the size of the pipeline), the length of the pipeline, the local resistance (the condenser in the chiller (can be found in the manual), and the control parts. Cooling water is a circulating system, you don’t need to consider the height difference, just add the height difference of the cooling tower. The pipe flow rate is generally about 1m/s, you can press: (pressure drop per meter of pipe mpa/m) i= Calculate with the formula 0.0000107×v×v÷d^1.3, where v is the average flow velocity (m/s), so the pump head is also determined.

The global demand for industrial process cooling system remains steadily rising. Reliability and minimal downtime are the keys to achieving consistent and profitable industrial and commercial processes. This article will consider the best way to achieve the optimal temperature required for production processes in the metal finishing, medical, brewing, and agricultural industries.

 

Glycol chiller VS water chiller

 

1: How does the chiller work?

 

So, how does the chiller work? The process circulates, but we will start from where the cooling medium is connected to your process equipment.

 

The coolant in the system absorbs the heat energy in the process, which usually causes a phase change to a gas. The gaseous refrigerant is then circulated to the condenser, which discharges heat through evaporative condensation or cooling towers. This heat exchange condenses the cooling medium into a colder liquid, which is sent back to the process heating source to start the cycle again.

 

What type of coolant is used in the chiller?

 

The type of coolant used in the chiller depends on the process requirements and cost considerations. The most popular coolant is water or a mixture of water and another substance with appropriate thermal conductivity (such as a glycol compound).

 

Water: Using water as a coolant is an economical method because in most cases, water can be easily obtained at the lowest cost. Alternatively, pure water (deionized water, reverse osmosis) can be used in a water-based chiller to achieve higher cooling efficiency.

 

Glycol: glycol-based coolants consist of ethylene glycol or propylene glycol. Although the two variants have similar physical properties, do not mix them. The main advantage of glycol coolant is to improve corrosion resistance and antifreeze performance.

 

2: Why use ethylene glycol for cooling

 

Compared with using ordinary water as the cooling liquid, the use of glycol-water mixture as the cooling liquid has many advantages. These advantages are due to its unique physical properties, including a lower freezing point than water.

 

Heat transfer between water and glycol

For water without impurities, its freezing point is 0°C, which is much higher than when pure ethylene glycol becomes solid at -13°C. When the mixture of ethylene glycol and water is changed, the freezing point of the coolant will also change. As an example, 10% ethylene glycol will freeze at -3.5°C, while a 60% ethylene glycol solution will freeze at -52°C.

 

It can be clearly seen from the above analysis that the refrigerant characteristics of ethylene glycol are more suitable for refrigerators that are expected to operate in a low temperature environment. Under these hot conditions, the cooling water can freeze and hinder the circulation of the chiller, while reducing overall efficiency.

 

In contrast, using a glycol-based chiller will take advantage of its antifreeze properties to ensure that the coolant maintains the desired fluid state.

 

3: glycol chiller VS water chiller

 

Both glycol chillers and chillers can be used to satisfactorily dissipate the heat generated during the production process. The fundamental difference between the two types of chillers is the change in their freezing point and thermal conductivity.

 

The freezing point of pure ethylene glycol or a mixture of ethylene glycol and water is much lower than that of pure water. This means that glycol-based chillers are more suitable for low-temperature environments. On the contrary, compared with glycol mixtures, water has a better ability to retain and conduct heat in related processes. As a result, the heat transfer efficiency for water chillers will be higher than glycol chillers.

 

In general, the operator needs to consider the ambient temperature of the location environment before choosing the type of chiller.

 

1. How does the glycol chiller system work?

 

Glycol chiller equipment consists of refrigeration components and pipes containing glycol-water mixture as coolant. The cooling fluid from the refrigeration unit is guided through pipes associated with the heat exchanger surrounding the heating process. After absorbing heat from the related process, the warmed coolant returns to the refrigeration unit for cooling, and then the process is repeated.

 

Glycol content in chilled water system

 

For many types of chillers, ethylene glycol is mixed with water in a 60/40 ratio. A higher percentage of ethylene glycol will greatly enhance the antifreeze performance of the mixture. This is useful in situations where rapid cooling is required. In these cases, the process can be cooled to very low temperatures without freezing the coolant in the pipeline.

 

How does the chiller system work?

 

Conventional water chillers work according to the principle of heat transfer between fluid and solid media. These cooling systems work by endothermic or vapor compression. The basic components of the water chiller system include a refrigeration unit and a piping system for circulating cooling coolant.

 

In the past ten years, oumal chillers have been manufacturing high-quality industrial chillers. With impressive water-cooled and air-cooled chillers, your industrial refrigeration needs will surely be met.

The Industrial Cooling Systems Chillers has a wide range of applications, including the plastics industry, electronics industry, food industry, chemical industry, electroplating industry, pharmaceutical industry...... The following takes the electroplating industry as an example. Oumal Refrigeration Machinery teaches you how to choose a suitable electroplating chiller.

We know that in electroplating production, the electroplating solution continuously generates heat in the electroplating reaction, so that the temperature of the electroplating solution gradually rises. When the temperature of the electroplating solution is higher than the process requirements, the firmness of the surface coating of the produced electroplated products is affected. Uniformity, flatness and surface finish have a greater impact. Choosing the chilled water provided by the chiller to cool and maintain the constant temperature of the electroplating solution will greatly improve the electroplating production process and production efficiency.

The electroplating industry uses the electroplating chiller to produce the effect: The electroplating solution cools, so that the metal and non-metal molecules are stabilized, and the chiller makes the metal molecules quickly adhere to the surface of the plated part with a stable current, increasing the density and smoothness of the plated part, and shortening The electroplating cycle improves the quality and can effectively recover all kinds of expensive chemical substances. The same applies to industrial refrigeration equipment in the vacuum coating industry. When choosing an electroplating chiller, we must first consider whether to use direct cooling or indirect cooling.

Direct cooling means that the electroplating solution directly enters the evaporator of the chiller through the filter or filter screen to cool down, and then returns to the oxidation tank. The advantage of the direct cooling method is that the cooling time is short and the effect is good. The disadvantage is that the evaporator needs anti-corrosion treatment (usually titanium alloy). It is easy to scale in the evaporator and needs to be cleaned regularly, otherwise it will affect the cooling effect and machine operation.

Another indirect cooling method is to lay titanium pipes in the oxidation tank. The chilled water takes away the heat of the electroplating solution through the titanium pipes to achieve the purpose of cooling. If it is inconvenient to lay the titanium pipes, you can add a heat exchanger (a titanium alloy is required). Cheng) While walking the frozen water, while walking the electroplating solution.

For the selection of electroplating chillers, we generally need to consider the following points: rectifier current (ampere), voltage (volt), number, electroplating tank length*width*height*80%, time, temperature difference. The electroplating liquid enters the chiller, and the evaporator, water pipe and pipeline are selected according to the degree of corrosiveness of the liquid. If the electroplating liquid does not enter the chiller, you need to know the material and area of the plate required in the tank. The heat comes from the rectifier or there are other places.

Calculation method for selection of chillers in electroplating industry:

Calorie calculation formula

Q=I*V*F*N

Q: Cooling capacity W

I: Rectifier current (Ampere)

V: Rectifier voltage (Volt)

N: Number of rectifiers

1KVA is about 0.75KW

 

Temperature difference method:

Q =1000*V*P*C*DT/S

Q: Cooling capacity (KW)

qv: volume of cooling medium (m3)

P: The density of the cooling medium (g/cm3 or Kg/L) water is 1g/cm3 or 1Kg/L

C: The constant pressure specific heat capacity of the cooling medium (J/Kg ℃) Water is 4186.8 J/Kg ℃)

DT: Temperature difference between inlet and outlet of cooling medium (℃) T2-T1

S: cooling time (S)

 

Supplementary note:

The cooling capacity of the chiller varies with the ambient temperature and the temperature of the outlet water

The actual heat generation of the equipment will also change due to different workpieces, molds, parameters, etc.

After the chiller is used, the temperature drops, and the surface temperature of the connecting pipeline, water tank, fuel tank, mold, spindle, and equipment will be lower than the ambient temperature, so it will absorb heat and increase the load.

In the actual application of industrial cooling, many situations cannot be accurately calculated by the above methods. At this time, it can only be estimated by empirical data and analogy of similar equipment.

 

Features of Oumal electroplating chiller:

1. Mainly use Panasonic, Copeland, and other famous brand fully enclosed scroll compressors, single or double, with high energy efficiency.

2. Brand refrigeration accessories, high-efficiency evaporator condenser, good refrigeration effect, reliable operation

3. Brand water pump, high pressure, high stability, durable

4. Microcomputer control panel, simple operation, high precision, wide range of use, can accurately control the water temperature

5. Complete electrical protection system, with phase loss, phase error protection, current overload protection, high and low voltage protection, etc. to ensure the normal operation of the unit

6. The water-cooled and air-cooled specifications are complete and can be customized according to customer needs.

 

Oumal specializes in producing all kinds of chillers, air-cooled chillers, water-cooled chillers, screw chillers, low-temperature chillers, glycol chillers, etc. Welcome to consult.

How to clean a water chiller?

As a fixed asset of an enterprise, the chiller is a must for enterprise personnel to maintain it and maximize its usefulness. Because the long-term operation of the chiller will cause thick scale on the surface of the condenser, which will interfere with the normal operation of the chiller. For example, to make its work efficiency low or easy to damage, etc., the necessary cleaning of the chiller is absolutely indispensable.

How to clean the chiller? We have to distinguish between water-cooled and air-cooled. The water-cooled chiller is mainly used to remove the scale of the chiller. The removal cycle depends on the water quality. If the water quality is poor, it is cleaned at least once every 12 months; if the water quality is good, it can be cleaned once every 2 years on average.

 

Air-cooled chillers use air as the cooling medium. Because there is often dust in the air, some of the dust will stick to the outer surface of the condenser fins. After a period of time, the cooling effect of the condenser of the chiller will gradually deteriorate. The local environment is relatively harsh, and it is easier to age quickly. Therefore, the maintenance and cleaning of the chiller should be carried out at regular intervals.

 

The cleaning method of air-cooled chillers is: there are more dirt in the maintenance and cleaning of chillers, and non-corrosive cleaning agents should be used to clean the radiating pipes and fins to achieve the purpose of improving the heat dissipation effect.

So let's briefly talk about the main steps of cleaning the chiller.

 

First, remove the parts

If you want to clean the chiller, you must first disassemble it, because the parts you want to clean are not easy to see inside the collective. The various parts of the chiller cross each other, and the lines are complicated and it is really difficult to dismantle. This is to understand the overall chiller structure.

 

Second, the connection between the cleaning equipment and the condenser

After the disassembly in the previous step, find the direction of the condenser water inlet and connect it to the water inlet or outlet of the water pump, and then use tools to heat the pipe.

 

Third, dosing and cleaning

After making sure that each step is done and the pipes are connected, first add clean water for cleaning for about twenty times, and then drain the sewage and repeat it 3 times. After the cleaning is completed, the most important dosing cleaning is done. Of course, its pH value must be guaranteed between 4-5 and maintained for 2-3 hours. Finally, the medicine is discharged, and then the residual medicine is flushed to keep the pH at 6.5.

 

Fourth, install back to the original state

After cleaning, the installation is completed as it was.

 

The above are the main steps for cleaning the chiller. Is it easy, but I think it’s better to ask professionals to clean it. After all, disassembling the machine can easily cause damage to the parts. If the chiller is broken to clean the machine, it can It's really not worth the gain.

The calculation method of chiller cooling capacity and the calculation summary of chiller selection

(1) How to choose the most suitable industrial chiller and screw chiller? In fact, there is a simple selection formula:

Cooling capacity = chilled water flow * 4.187 * temperature difference * coefficient

1. The flow rate of chilled water refers to the flow rate of chilled water required when the machine is working, and the unit needs to be converted into liters/second;

2. The temperature difference refers to the temperature difference between the water in and out of the machine;

3. 4.187 is quantitative (specific heat capacity of water);

4. When choosing an air-cooled chiller, multiply the coefficient by 1.3, and when choosing a water-cooled chiller, multiply it by 1.1;

5. Select the corresponding machine model according to the calculated cooling capacity.

It is generally customary to use HP to calculate how much the chiller needs to be equipped, but the most important thing is to know the rated cooling capacity. Generally, the air-cooled cooling capacity is 9.07KW and the 3HP chiller is selected, and so on. Therefore, the most important thing in the selection of industrial chillers is to obtain the rated cooling capacity.

(2) The calculation method of the cooling capacity of the chiller

How to calculate the cooling capacity of the chiller

1. Volume (liter) X number of temperature rise / heating time (minute) X 60 / 0.86 (coefficient) = (W)

2. Volume (tons or cubic meters) X number of temperature rise / heating time / 0.86 (coefficient) = (KW)

(3) Selection method of chiller

Energy conservation law Q=W in-W out

Q: Heat load (KW) W in: Input power (KW) example: 8KW, W out: Output power (KW) example: 3W

Example: Q=W in-W out=8-3=5 (KW)

Time heating method Q=Cp.r.V.ΔT/H

Q: Heat load (KW) Cp: Specific heat at constant pressure (KJ/kg.℃)……4.1868 KJ/kg. ℃,

r: Specific weight (Kg/m3)………1000 Kg/m3 V: Total water volume (m3) Example: 0.5m3

ΔT: water temperature difference (℃)…… ΔT= T2-T1 example: 5℃ H: time (h) example 1h

Example: Q=Cp.r.V.ΔT/H=4.1868*1000*0.5*5/3600=2.908 (KW)

Temperature difference flow method Q=Cp.r.Vs.ΔT

Q: Heat load (KW) Cp: Cp: Specific heat at constant pressure (KJ/kg.℃)……4.1868 KJ/kg. ℃,

r: Specific weight (Kg/m3)…….1000 Kg/m3 Vs: Water flow rate (m3/h) Example: 1.5m3/h

ΔT: water temperature difference (℃)…… ΔT= T2 (outlet water temperature)-T1 (inlet water temperature) Example: 10°C

Example: Q=Cp.r.Vs.ΔT=4.1868 * 1000 * 1.5* 10/3600 = 17.445 (kw)

Common plastic method: Q=W* C*ΔT * S

Q=the required frozen water energy kcal/h W=the weight of plastic raw materials KG/H Example: W=31.3KG/H

C=Specific heat of plastic raw materials Kcal/KG ℃ Example: Polyethylene PE C=0.55 Kcal/KG℃

ΔT= is the temperature difference between the melting temperature and the product film, ℃ generally (200℃)

S = safety factor (take 1.35-2.0) Generally take 2.0

Example: Q= W* C*ΔT * S=31.3 * 0.55 * 200 * 2.0 = 6886 (kcal/h)

When you need a chiller, Here is the Necessary info to quote.

1.What is your cooling capacity?_____    Kcal/hr  or   _____KW or _____RT?
2. What's your power supply? For example: 380V-50Hz-3N (N=Phase )
3.What refrigerant type do you require? R22 or R134a or R407c?
4. What's your ambient temperature?

And what is your chiller inlet and outlet water temperature?
5. Which industry do you use the chiller in?

Commonly used auxiliary accessories for low temperature chillers, including water flow switch, pressure controller, pressure difference controller, temperature controller and solenoid valve, as well as a brief introduction of three cooling methods, liquid vaporization refrigeration, gas expansion refrigeration and thermoelectric refrigeration.

Common auxiliary accessories for low-temperature chillers

1, water flow switch

The water flow switch is used as the control or cut-off protection of the fluid flow in the pipeline. When the fluid flow reaches the set value, the switch automatically cuts off (or connects) the circuit.

2, pressure controller

The pressure controller is used for pressure control and pressure protection. The chiller has low and high pressure controllers to control the working range of the system pressure. When the system pressure reaches the set value, the switch automatically cuts off (or connects) the circuit.

3, differential pressure controller

The pressure difference controller is used to control the pressure difference. When the pressure difference reaches the set value, the switch automatically cuts off (or turns on) the circuit.

4, temperature controller

The temperature controller is used for the control or protection of the unit. When the temperature reaches the set value, the switch automatically cuts off (or turns on) the circuit. In our products, temperature control is often used, and the temperature of the water tank is used to control the startup and shutdown of the unit. There are also temperature controllers that need to be used for antifreeze.

5, solenoid valve

Cut off the system circuit when the compressor is stopped to avoid liquid shock when the compressor is started next time. It is generally used in a larger refrigeration system.

Three cooling methods

1. Liquid vaporization refrigeration:

1) Compression: The normal temperature gas state becomes a high pressure and high temperature gas state.

2) Condensation: High pressure and high temperature gas becomes high pressure liquid

3) Evaporation: High-pressure liquid turns into low-pressure gas, absorbing heat and realizing refrigeration.

 

2, gas expansion refrigeration:

Gas expansion refrigeration uses the adiabatic expansion of high-pressure gas to reach low temperature, and uses the reheating process of the expanded gas at low pressure to refrigerate. Due to the different equipment for gas adiabatic expansion, there are generally two ways: one is to increase the high pressure The gas is expanded by the expander and has external power output, so the temperature drop of the gas is large, and the cooling capacity is also large during reheating. However, the expander structure is more complicated. Another way is to make the gas expand through the throttle valve without external power output. The temperature drop is small and the cooling capacity is small, but the structure of the throttle valve is relatively simple, which is convenient for the adjustment of the gas flow.

 

3. Thermoelectric cooling

When the DC power supply is turned on, the current direction of the upper connector is N-P, the temperature decreases, and absorbs heat, forming a cold end; the current direction of the lower connector is p-n, the temperature rises, and heat is released, forming a hot end. Several pairs of thermocouples are connected to form a commonly used thermopile. With the help of various heat transfer devices, the hot end of the thermopile continuously dissipates heat and maintains a certain temperature, and the cold end of the thermopile is placed in the working environment to absorb Heat, produce low temperature, this is the working principle of semiconductor refrigeration. The solar semiconductor refrigeration system uses the thermoelectric cooling effect of semiconductors to directly supply the required DC power by solar cells to achieve the effect of cooling and heating.

If you need to know more about low-temperature chillers, glycol chillers, screw chillers, chillers, ice water chillers, scroll chillers, piston chillers and refrigerators and other refrigeration products, please contact our OUMAL refrigeration manufacturer, and we will try our best to solve the failure of the chiller for customers. Such as chiller does not refrigerate and other issues, wholeheartedly recommend customers to choose the right chiller products, so that everyone can buy the right machine and solve your industrial cooling water system issue. Welcome to consult us at any time. The oumal industrial chiller water unit adopts original imported configuration, fully automatic computer controller, which can precisely control the temperature of the coating machine. According to customer requirements, different methods of use are developed to produce refrigeration equipment that meets customer requirements to ensure the high quality of plating parts. .

After the industrial chiller system has passed the vacuum test, the vacuum state in the system can be used to charge the refrigerant.

1. Refrigerant charging

For newly installed systems, refrigerant can be added to the high-pressure end, and the operation method is as follows:

1) Turn on the cooling water system for the condenser, and keep the valve in the system as it was during the vacuum test

2) Connect the steel cylinder containing the refrigerant with the West 14mm×2mm seamless steel pipe (use a red copper pipe when filling with Freon). The mouth of the bottle is inclined downward, and the cylinder is at an angle of 30° with the ground, or the end of the cylinder is raised about 200-300mm.

3) Open the filling valve. When the system reaches a certain pressure (0.1～0.2 MPa for ammonia system; 0.2～0.3 MPa for Freon system), stop charging the refrigerant, and then check the sealing condition of the system at each connection and welding place. If there is no leakage, Can continue to charge refrigerant.

4) Close the outlet valve on the liquid reservoir and continue to charge the refrigerant. When the cylinder pressure and the pressure in the liquid reservoir reach equilibrium, the outlet valve on the liquid reservoir should be opened.

5) Start the refrigerating machine, make the refrigerating device enter the running state, and continue to charge the refrigerant at the same time. When white frost appears on the lower part of the cylinder, it means that the liquid refrigerant in the cylinder is almost completely filled. At this time, the cylinder valve and charging valve can be closed, and the bottle can be changed to continue charging.

6) Unless the outside temperature is very low, it is generally not necessary to pour hot water on the cylinder to increase the pressure in the cylinder when charging the refrigerant, because it is not safe to do so. If you need to speed up the filling speed, the hot water temperature must not exceed 50°C and other methods to heat the cylinder are strictly prohibited.

7) When filling freon, a filter drier must be installed on the special nozzle to reduce the possibility of water entering the system. When charging with high pressure section, never start the compressor, and pay attention to the exhaust valve not to leak, otherwise liquid hammer will occur.

8) When the refrigerant is charged up to 90% of the charging amount, the charging can be temporarily stopped, and the system can be tested to check whether the system dosage has met the operation requirements and avoid unnecessary trouble caused by excessive charging. For the old refrigeration system, when the refrigerant needs to be supplemented, it should be charged from the low pressure side.

2. Leak detection after filling

(1) Leak detection method with test paper Generally, phenolphthalein test paper is used to test the system's welds, flanges, and threaded connections for leaks. Wet the test paper and approach the inspected place. If it turns red, it means that there is ammonia leakage (note that the test paper should not be in contact with the soapy water on the pipe to create an illusion). Litmus paper that turns blue when exposed to ammonia can also be used.

(2) Halogen blowtorch leak detection method Halogen blowtorch is a common tool for leak detection in Freon refrigeration systems. The domestic halogen blowtorch is shown in the figure below, and the method of use is as follows:

1. Add alcohol: first unscrew the base 1 and add anhydrous alcohol with a purity of not less than 99.5% to the inside of the barrel, but the amount of injection should not be too much, just fill 1/2 to 3/4 of the volume of the lamp tube That's it, then the base should be fastened tightly.

2. Light a fire: turn the hand wheel 2 to the right, close the valve core, fill the wine glass, and then light it to heat the lamp tube and the upper part of the blowtorch. After heating a little, check whether the blowtorch is leaking.

3. Fire: When the alcohol in the beaker is nearly finished, turn the hand wheel 2 to the left and ignite the volatilized alcohol in the nozzle in the flame ring 4. At this time, the suction hose 6 of the halogen lamp emits With the sound of gas inhalation, you can start leak detection with a lamp.

4. Use: When testing, move the nozzle of the suction hose 6 close to the inspected place, and move slowly. If there is Freon gas leakage, it will decompose when it meets the flame. At this time, the orange-red flame will turn into green and the color of the flame. The change varies with the amount of Freon leakage, and the darker the color, the more serious the leakage of Freon.

The air-cooled screw chiller is a screw chiller that uses fans to dissipate heat. The installation environment it needs must be open and easy to circulate, so that this operation will not affect the cooling effect of the air-cooled screw chiller .

 

Therefore, we should understand some common faults of air-cooled screw chillers and some troubleshooting methods:

 

1. The fan noise of the air-cooled screw chiller is too loud

 

Bearing component wear/excessive clearance: If it is worn, it should be replaced in time, and if the clearance is too large, it can be directly adjusted to a suitable position;

 

The speed is too high: it can be improved by reducing the speed, if it is not solved, replace the fan;

 

2. The temperature rise of the motor of the air-cooled screw chiller fan is too high

 

The flow exceeds the rated value: the valve needs to be closed at this time;

 

Motor or power supply problems: find out the reasons for the motor and power supply;

 

3. The bearing temperature of the air-cooled screw chiller fan increases

 

The fan shaft and the motor shaft are different: they need to be adjusted to be concentric;

 

Bearing damage: need to replace a new bearing, or directly contact the chiller manufacturer to replace it.

 

Insufficient lubricating oil (grease) or poor quality: If the lubricating oil is not enough, the company should fill it up to the required part; if there is a quality problem, it is necessary to clean the bearing or replace the more qualified lubricating oil (grease);

 

4. The air output of the air-cooled screw chiller fan is too small:

 

Blockage of air inlet, outlet and pipe: check and remove the blockage;

 

Insufficient valve opening, speed, and belt slack: you can check the bearing by adjusting the valve opening to a proper opening, tightening and replacing the belt, and checking the voltage.

 

Check that the connection between the impeller and the shaft is loose, which can be eliminated by direct prohibition; if the gap between the impeller and the air inlet is too large, it should be adjusted to a suitable gap.

 

The fan of the air-cooled screw chiller is equivalent to the cooling tower cooling system of the water-cooled chiller. If the heat dissipation effect is not good, the cooling capacity of the air-cooled screw chiller is absolutely insufficient, which directly affects the company’s refrigeration Water demand. Therefore, we need to maintain and maintain our chillers in a timely manner.

What caused poor refrigerating efficiency?

Sometimes when we use a chiller, but the temperature could not be lower, or After cooling down to a certain temperature, it won’t go down anymore. Let's talk What caused the poor refrigerating efficiency ?

1. Refrigerant leakage

[fault analysis] After the refrigerant leak in the system, the cooling capacity is insufficient, the suction and exhaust pressure are low, and the expansion valve can hear much larger intermittent “squeak” air flow than usual.The evaporator is not frosted or with a small amount of frosting. If the expansion valve hole is enlarged, the suction pressure remains unchanged.After the shutdown, the equilibrium pressure in the system is generally lower than the saturation pressure corresponding to the same ambient temperature.

2. Too much refrigerant is filled after maintenance
[fault analysis] When the refrigerating dose filled in the refrigeration system after maintenance exceeds the capacity of the system, the refrigerant will occupy a certain volume of the condenser, reduce the heat dissipation area, and reduce its refrigeration efficiency. Generally, the suction and exhaust pressure are higher than the normal pressure value, the evaporator is not frosted, and the temperature in the warehouse is slow.

3. Air in the refrigeration system

[fault analysis] The air will reduce the refrigeration efficiency in the refrigeration system. The prominent phenomenon is the increase of suction and exhaust pressure (but the exhaust pressure has not exceeded the specified value). The temperature of the compressor at the inlet of the condenser is significantly increased.

4. Low compressor efficiency

[fault analysis] The low efficiency of refrigerating compressor refers to the reduction in the response of refrigerating volume due to the decrease of the actual exhaust volume under the condition that the working condition remains unchanged.This phenomenon usually occurs on compressors that have been used for a long period of time, with large wear and tear, large clearance of all components, and decreased sealing performance of air valves, which results in the decrease of actual air discharge.

5. The surface of evaporator is frosted too thick
[fault analysis] Long-term use of cold storage evaporator should be regularly defrosted. If the frost is not defrosted, the frost layer on the evaporator tube becomes thicker and thicker. When the whole pipeline is encased in transparent ice, the heat transfer will be seriously affected, causing the temperature in the reservoir to fall below the required range.

6. There is frozen oil in the evaporator pipeline
[fault analysis] During the refrigeration cycle, some frozen oil remains in the evaporator pipeline. After a long period of use, a large amount of oil remains in the evaporator, which will seriously affect its heat transfer effect and lead to poor refrigeration.

7. The refrigeration system is not smooth
[fault analysis] Because the refrigeration system is not clean, after several hours of use, the dirt is gradually silted up in the filter and some mesh holes are blocked, resulting in the reduction of refrigerant flow and affecting the refrigeration effect.
In the system the expansion valve, the compressor suction nozzle at the filter screen also has a small plug phenomenon.

8. The filter is blocked
[fault analysis] When the desiccant is used for a long time, it becomes paste to seal the filter, or the dirt gradually accumulates in the filter, causing blockage.

9. Leakage of refrigerant in the expansion valve sensible temperature package
[fault analysis] After the leakage of the temperature sensor in the expansion valve’s temperature sensor package, two forces under the diaphragm push the diaphragm upward. It is the valve hole closed.

10. Cold air cooling condenser has poor cooling effect in the cold storage
[fault analysis]
⑴The fan is not on.
⑵Parliamentary fan motor damaged.
⑶Torque fan reverse.
⑷high ambient temperatures (40 ℃ above).
⑸Flow of condenser cooling fins blocked by oil and dust.

11. The cooling effect of water-cooled condenser is poor
[fault analysis]
⑴The cooling water valve is not opened or opened too small, and the inlet pressure is too low
⑵Potassium water regulating valve fails.
⑶The scale on the wall of the condenser pipe is thicker.

12. Too much refrigerant is added into the system
[fault analysis] Too many refrigerants lead to a significant increase in the exhaust pressure, exceeding the normal value.

13. Residual air in the system
[fault analysis] The air circulation in the system will lead to excessive exhaust pressure, high exhaust temperature, hot exhaust pipe, poor refrigeration effect, the compressor will operate soon, and the exhaust pressure will exceed the normal value.

14. Stop when the suction pressure is too low
[fault analysis] When the suction pressure in the system is lower than the set value of the pressure relay, its contact action will cut off the power supply.

15. The temperature controller is out of control
[fault analysis] The thermostat fails to adjust or the temperature sensor package is improperly installed.

16. Sudden stop caused by other reasons
[fault analysis] In the process of use and maintenance, it is often necessary to open, close the exhaust, inhale, and store the liquid, etc.

Industrial chillers are one type of chillers, and chillers can be divided into air-cooled chillers and water-cooled chillers.

Water chiller is a kind of water cooling equipment, which can provide constant temperature, constant current and constant pressure cooling equipment. The principle of the chiller is to inject a certain amount of water into the internal water tank of the machine, and the water is cooled by the chiller refrigeration system, and then a water pump inside the machine injects low-temperature frozen water into the equipment that needs to be cooled, and the chilled water will heat the internal heat of the machine. Take it away and return the high-temperature hot water to the water tank to cool down again. In this way, it is circulated and exchanged and cooled to achieve the effect of cooling the equipment.

In industrial applications, chilled water or other liquid cooling pumps are passed through processes or laboratory equipment. Industrial chillers are used in various industries to control the cooling of products, mechanisms and factory machinery. They are commonly used in injection and blow molding in the plastics industry, metal processing cutting oils, welding equipment, die-casting and machining, chemical processing, pharmaceutical formulation, food and beverage processing, papermaking, cement processing, vacuum systems, X-ray diffraction, electric power Supply and power stations, analytical equipment, semiconductors, compressed air and gas cooling. They are also used to cool high heat energy, such as MRI machines and laser specialized engineering projects, and in hospitals, hotels and campuses. The chillers for industrial applications can be centralized, and each chiller can meet multiple needs for cooling, or be dispersed in each application or device with its own chiller. Each method has its advantages. It may also have a combination of central and decentralized chillers, especially when the cooling requirements are the same for certain applications or use points, but not all.

Distributed chillers have a small area (cooling capacity) usually from 0.2 tons to 10 tons. Central chillers generally have a capacity ranging from 10 tons to hundreds or thousands of tons.

Chilled water is used to cool and dehumidify the air in large-scale commercial, industrial and institutional alliance (CII) facilities. The chiller can be water-cooled, air-cooled, cooled or evaporatively. The use of water-cooled chillers is incorporated into cooling towers, which improves the cooling' thermodynamic efficiency compared to air-cooled chillers. This is due to the high temperature or the wet bulb temperature of the nearby air, rather than repelling the high, sometimes much higher, dry bulb temperature. Evaporatively chillers provide better efficiency than air cooling, but lower than cold water.

Several aspects of the chiller should be paid attention to:

1. Selection of model size of chiller for injection molding machine

When used as a mold cooling of an injection molding machine, it can be calculated according to the injection volume of the injection molding machine. Generally, a 1HP chiller is used for every 6 ounces of injection volume. For example, the customer’s factory is 100T (5.5OZS)×3; 150T(12OZS)×4 units; 200T(23OZS)×3 units; the required chiller size is (5.5×3+12×4+23×3)/6=22.25, that is, a 25HP chiller. When used for cooling of other equipment, it depends on the specific flow rate of the cooling water circulation.

2. Selection of the insulation water tank and water pump of the chiller

Sometimes according to the actual situation of the customer's factory, the box-type chiller may also require an external pump. At this time, the additional pump model must have the same power as the pump that comes with the chiller. If the 10HP box-type chiller comes with a pump power of 2HP, when the pump is added, it must also be 2HP.

3. The temperature of the return water of the chiller should not be higher than 40 degrees. The higher the return water temperature, the greater the damage to the compressor.

Scope of application

Plastic industry: Accurately control the mold temperature of various plastic processing, shorten the plastic molding cycle, and ensure the stability of product quality.

Electronics industry: Stabilize the molecular structure of electronic components on the production line, improve the qualification rate of electronic components, and apply to the ultrasonic cleaning industry to effectively prevent the volatilization of expensive cleaning agents and the damage caused by volatilization.

Electroplating industry: control the electroplating temperature, increase the density and smoothness of the plated parts, shorten the electroplating cycle, increase production efficiency, and improve product quality.

Machinery industry: Control the oil temperature of the oil pressure system, stabilize the oil temperature and oil pressure, extend the oil quality use time, improve the efficiency of mechanical lubrication, and reduce wear.

Construction industry: supply chilled water for concrete, make the molecular structure of concrete suitable for construction purposes, and effectively enhance the hardness and toughness of concrete.

Vacuum coating: control the temperature of the vacuum coating machine to ensure the high quality of the coated parts.

Food industry: used for high-speed cooling after food processing to adapt to packaging requirements. In addition, there are control of the temperature of fermented food and so on.

Pharmaceutical industry: In the pharmaceutical industry, it is mainly used to control the temperature control of fermented drugs. Pharmaceutical companies should make full use of chiller equipment, continue to strengthen technological innovation based on their advantages, and enhance the cost-effectiveness of chillers, so as to better serve the pharmaceutical sector.