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Reasons and solutions for the internal protection of screw compressors | Oumalchiller.com

2025-06-20

The compressor is the heart of the chiller, and the normal operation of the compressor is the basis for the normal operation of the chiller. Therefore, if we want to understand the chiller, we must first understand the compressor. Today we will talk about the reasons for the internal protection of the semi-hermetic screw compressor. There is a thermal switch inside the screw compressor. The function of this switch is to disconnect the power supply circuit to the motor of the compressor when the temperature of the compressor exceeds the set value, and the compressor can not be turned on until the compressor is cooled down. And compressor Work. This is the internal protection of the compressor. Today we will talk about the reasons and solutions for this situation.

screw compressor chiller

1.The refrigeration system is short of refrigerant. When the refrigerant is insufficient, the refrigerant returning to the compressor will be overheated, causing the compressor to heat up as a whole, causing the thermal switch to act, resulting in thermal protection of the compressor.

Solution: Add enough refrigerant, and the return pipe of the compressor should be cool when it is turned on.


2.If the condensing pressure of the compressor is too high, the cooling water or the ambient temperature is too high, the exhaust pressure of the compressor will be too high, resulting in the exhaust temperature being too high, and the compressor will be overheated.

Solution: clean the condenser, or increase the cooling water flow pressure.


3.The chiller model we chose is wrong, it is small. When the compressor selection is too small, there will be a small horse-drawn cart, the chiller will never reach the set temperature, and the compressor will continue to work until the compressor is thermally protected.

Solution: To re-select a new chiller, there must be an amplification factor to ensure that the chiller can reach the set temperature and stop.


4.If the compressor motor fails, the insulation of the enameled wire will be poor, which will cause the compressor current to be too large, and it will also be thermally protected.

Solution: Contact the chiller manufacturer to repair the compressor or replace the compressor.


OUMAL CHILLER is a professional screw chiller manufacturer. We use High quality screw compressor Hanbell Brand compressor and Bitzer screw compressor. The Screw chiller type including air cooled screw chiller and water cooled screw chiller from 30 ton to 500 ton. Also including low temperature screw chiller and glycol chiller. If you are looking for a industrial screw compressor chiller please call us to get the latest price.


The difference between direct cooling and indirect cooling of industrial chillers

2025-06-20

The industrial chiller is a refrigeration equipment that can provide industrial cooling water. Industrial chiller is used in a wide range of industries, such as: electroplating, plastics, electronics, food, card making, chemical industry, machining, laser and other industries. There are two cooling methods for the chiller, one is direct contact between water and the material to be cooled, and the other is indirect contact. In the industrial production process, in order to cool the production medium, in order to ensure that the production equipment works at a normal temperature, to absorb or transfer the excess heat of the production medium or production equipment, cooling water is used. The cooling water and the cooled medium are separated by the heat exchanger wall or equipment, which is called indirect cooling water.


Direct cooling water refers to the cooling water that is in direct contact with the product or semi-finished product for cooling in order to meet the needs of the process during the production process, which is called direct cooling water. It includes direct-flow spray water for temperature and humidity regulation.

When the chiller is working, its freezing method can be selected according to customer needs, direct cooling and indirect cooling.


direct cooling water system-air cooled screw chiller


There are also various cooling media. According to different cooling liquids, some liquids that need to be cooled cannot contact the cooling water or cooling medium in the chiller, such as electroplating liquids with strong corrosiveness, such as the food industry, especially milk cooling, is the evaporator that cannot touch the chiller. Therefore, the chiller needs to indirectly cool the milk and the electroplating liquid. A detachable plate heat exchanger is added between the chiller and the liquid to be cooled. One side takes the chilled water, and the other side takes the milk or electroplating liquid, so that the milk can be cooled. No pollution, and the plating solution will not corrode the evaporator of the chiller. There are also many indirect cooling methods in the electroplating industry, such as laying titanium tubes in the oxidation tank, and the chilled water takes away the heat of the electroplating solution through the titanium tubes to achieve the purpose of cooling. made), while the chilled water is taken, the plating solution is taken.


The direct cooling method is most used, and there is no requirement for water quality. The chilled water is directly connected to the equipment that needs to be cooled for cooling. The effect of direct cooling is better than that of indirect cooling.


Oumal specializes in the production of various industrial chillers, matching materials and customizing professional industrial cooling water systems according to the needs of customers for direct cooling and indirect cooling. Buy an industrial chiller, Call us to get the latest price.


The lubrication method of the internal components of the screw chiller

2025-06-20

Screw compressor chillers can be divided into air-cooled screw chillers and water-cooled screw chillers according to different heat dissipation methods. According to different temperatures, it can also be divided into low temperature screw chillers, and according to the protection method, there are explosion-proof screw chillers. Explosion-proof screw chillers are mainly used in the chemical industry. The core components-compressors of these screw chillers are screw-type series of well-known brands, such as: Taiwan Hanbell screw compressor, Germany Bitzer screw compressor, the lubrication effect is very good, and the service life is over 20 years.


Air cooled screw compressor chiller


When the compressor lubrication system of the screw chiller is better, it can reduce the friction force, friction heat and wear of parts of the compressor, better improve the mechanical efficiency of the compressor, and increase the reliability and working life of the compressor. The compressor lubrication method of the screw chiller is divided into oil lubrication and oil-free lubrication. At present, oil lubrication is still the main method, and the dripping or splashing method is adopted, and the splashing method is the most widely used in screw compressors. a form. In this lubrication method, the air and the compressor oil are in close contact, which can play a better role in the operation of the compressor of the chiller.


So, what is the lubrication method of the refrigeration compressor of the screw chiller?

1. Splash lubrication: This method is generally used for small open or semi-hermetic compressors. It uses the crankshaft or accessories set on the crankshaft to contact the oil surface when rotating, so that the lubricating oil splashes and the friction parts are lubricated.


2. Centrifugal oil supply and lubrication: This method is generally used in fully enclosed compressors with vertical crankshaft installations. It uses the centrifugal force of the crankshaft to tell the rotation to make the lubricating oil in the center of the crankshaft move along the shaft to two directions under the action of centrifugal force. Side and upper flow to lubricate the friction parts.


3. Mechanical oil pump oil supply and lubrication: This method is generally used for medium and large compressors. It uses mechanical oil pumps (commonly there are gear pumps, rotor pumps, crescent pumps, etc.) to pump and press lubricating oil to each friction area.


The lubricating oil (that is, refrigeration oil) used in the refrigeration compressor of the screw chiller can enhance the sealing effect after filling the gap with the cylinder and the friction surface of the shaft seal, and can take away the wear debris and improve the friction surface. Working conditions, ensure the normal operation of the compressor, and improve the working efficiency of the entire chiller.


What are the advantages of water-cooled chillers?

2025-06-20

Water-cooled chillers are equivalent to air-cooled chillers, which are safer in operation and more conducive to maintenance and repair.


The high-quality compressor is the heart of the water-cooled chiller, and the compressors are all high-quality brand compressors. For scroll compressor water cooled chiller, We use Copeland, Danfoss, Panasonic, Daikin Brand, For screw compressor water cooled chiller, Bitzer and Hanbell or Refcomp compressor is the widely used in our screw water cooled chiller systems.


The water-cooled chiller condenser is made of high-efficiency external threaded copper tube, which is very small in size and has a very fast heat dissipation speed. It uses new CAD/CAM processing technology and is completed with CNC machining center. It has compact structure, high reliability, beautiful appearance and high efficiency. Energy saving, good heat dissipation, the refrigerant pressure is lower than that of air cooling, the energy efficiency ratio is higher than that of air cooling, and the cooling speed is faster.


The water-cooled chiller is equipped with a single-chip control system, built-in compressor drier filter and expansion valve, maintenance hand valve interface and other devices to ensure the reliable and safe operation of the machine and facilitate maintenance.


The water tank evaporator has a built-in automatic water replenishment device, which saves the expansion water tank in the engineering installation and facilitates installation and maintenance. It is suitable for special occasions such as large temperature difference and small flow.


The multi-function operation panel of the water-cooled chiller is equipped with an ammeter, a control system insurance, a compressor switch button, a water pump switch button, an electronic thermostat, various safety protection fault lights, and a unit startup and running indicator light, which is easy to operate and easy to apply.


high capacity water cooled screw chiller


1. Stable performance: multiple compressors are used in parallel, each compressor has its own independent refrigeration circuit, that is, the evaporator and condenser are also completely independent; all compressors are commanded by a unified microcomputer control system, which is turned on and off one by one , they will never interfere with each other. In addition, the brand machines are all made of original genuine products, and the single machine failure rate is extremely low. Based on the above reasons, this series of machines can be guaranteed to have a highly stable performance. Ideal equipment without the need to purchase additional spares.


2. Power saving and energy saving: multiple small and medium power compressors are used in parallel, the starting current is stable, and the interference to the power grid is very small when turning on and off. With the change of load, the unit will automatically determine the number of startups to ensure the compressors that are turned on. In a better working state, thereby effectively saving energy.


3. Long service life: The evaporator and condenser are very reasonably designed and placed above the compressor. During the entire operation process, most of the oil stays in the compressor to ensure good lubrication of the compressor.


4. Wide range of application: plastic products, molds, hardware, electroplating, chemical industry, electronics, food preservation, laser engraving, vacuum coating, ultrasonic cleaning; high-power chillers are widely used in hotels, office buildings for air conditioning, plastic cooling, food preservation , bath heating and cooling, medical storage and other industries.


5. Ergonomic panel, fully automatic control, equipped with precision electric temperature controller, can run smoothly for a long time.


6. The high-efficiency heat transfer heat exchanger is adopted, which has the advantages of less cooling loss, easy oil return, and no freeze cracking of the heat transfer tube.


7. High-performance compressors imported from Europe, Japan and the United States are used, with high EER value, low noise, and stable operation. 8. Using Schneider Electric, it is safe, stable and reliable in operation.


What are the differences between air-cooled chillers and water-cooled chillers

2025-06-20

We all know that according to different heat dissipation methods, chillers can be divided into air-cooled chillers and water-cooled chillers. What is the difference between air-cooled chillers and water-cooled chillers?


1. The air-cooled chiller uses copper tubes and aluminum fins to dissipate heat from the condenser. A fan is required to blow the outdoor air through the heat exchange fins and take away the heat of the condenser, so the air-cooled chiller does not need to be connected to the cooling tower. But compared with water-cooled chillers, under the same power, air-cooled chillers have larger equipment size and higher noise. The condenser of water-cooled chillers exchanges heat with the cooling water from the cooling tower through the heat exchanger. The excess waste heat will be transported to the cooling tower through the cooling water loop and released into the atmosphere, or enter the water-water heat exchanger or soil heat exchange coil for storage. Therefore, water-cooled chillers do not need fans to dissipate heat, but need cooling towers or water (ground) source heat exchange pipelines. Water-cooled chillers have one more cooling water system than air-cooled chillers. The size of the unit of the same power is smaller than that of the air-cooled chiller, it does not take up space, and the noise is lower, but it needs a cooling tower and the equipment needs a computer room.


2. In terms of refrigeration and heat exchange switching, the air-cooled chiller-type refrigerant loop switches the flow direction through a four-way valve to exchange the condenser and the evaporator. In summer, heat is transferred from indoor to outdoor, and in winter, it absorbs heat from outdoor. indoor. The water-cooled chiller does not have the ability of evaporator and condenser interchangeability, so the unit connected to the cooling tower does not have the heating function (requires an external boiler). The heat pump unit needs to switch the chilled water and cooling water loops, and 8 water circuit switching valves are added in the machine room. In summer, cold water enters the house, hot water enters the external coil, and winter hot water enters the house, and cold water enters the external coil. (Some small water source heat pump units also have refrigerant four-way valves)

air-cooled chillers vs water-cooled chillers


3. In the case of the same cooling capacity, the model of water-cooled chiller is smaller, because the energy efficiency ratio of water-cooled chiller is higher than that of air-cooled chiller, and the compressor of air-cooled chiller is better than water-cooled chiller. Great horsepower.


4. In terms of installation, the air-cooled chiller is easy to install, while the installation pipeline of the water-cooled chiller is more complicated.

 

If you don’t know whether to choose an air-cooled chiller or a water-cooled chiller when choosing a chiller, you can contact us. We will recommend to you a suitable chiller based on your on-site installation, the budget of the chiller, and the size of the model. Email: oumal@oumal.com

 

What causes the high-pressure failure of your water chiller machine? How to solve it?

2025-06-20

The high-pressure failure of the chiller means that the compressor discharge pressure is too high, which causes the high-pressure protection relay to operate. The compressor discharge pressure reflects the condensing pressure, the normal value should be 1.4~1.8MPa, and the protection value setting is recommended not to exceed 2.0MPa. Because the long-term pressure is too high, it will cause the compressor to run too much current, easily burn the motor, and cause damage to the compressor. So what is the main cause of high pressure failure? How to solve it?


water cooled chiller system


1. Excessive refrigerant charge. This situation generally occurs after maintenance, and it is manifested as high suction and discharge pressure and balance pressure, and the compressor operating current is also high.


Solution: The refrigerant should be discharged according to the suction and discharge pressure and the balance pressure and the operating current under the rated conditions until it is normal.


2. The cooling water temperature is too high and the condensing effect is poor. The rated working conditions of the cooling water required by the chiller are between 30 and 35. High water temperature and poor heat dissipation will inevitably lead to high condensing pressure. This phenomenon often occurs in high temperature seasons.


Solution: The reason for the high water temperature may be the failure of the cooling tower, such as the fan is not turned on or even reversed, the water distributor does not turn, it is manifested as the cooling water temperature is very high, and it rises rapidly; the outside temperature is high, the water path is short, and it can be circulated In this case, the cooling water temperature is generally maintained at a relatively high level, which can be solved by increasing the storage tank.


3. The cooling water flow is insufficient, and the rated water flow cannot be reached. The main performance is that the pressure difference between the inlet and outlet water of the unit becomes smaller (compared with the pressure difference at the beginning of the system's operation), and the temperature difference becomes larger.


Solution: The pipeline filter is clogged or the selection is too fine, and the water permeability is limited. Choose a suitable filter and clean the filter regularly; or the water pump is small and does not match the system.


4. The condenser is fouled or blocked. Condensate water generally uses tap water, it is easy to scale when it is above 30, and because the cooling tower is open, it is directly exposed to the air, dust and foreign matter can easily enter the cooling water system, causing the condenser to be dirty and blocking, and the heat exchange area is small. The efficiency is low, and it also affects the water flow. The performance is that the pressure difference and temperature difference between the inlet and outlet water of the unit become larger, the upper and lower temperatures of the condenser are very high when the condenser is touched by hand, and the condenser outlet copper pipe is hot.


Solution: The unit should be backwashed regularly, and chemical cleaning and descaling should be carried out if necessary.


5. False alarms caused by electrical faults. Because the high-voltage protection relay is damp, poorly contacted or damaged, the unit electronic board is damp or damaged, and the communication failure causes a false alarm.


Solution: For this kind of false fault, the HP fault indicator on the electronic board is often off or slightly bright, and the manual reset of the high-pressure protection relay is invalid. The running current of the compressor is normal, and the suction and exhaust pressures are also normal.


6. The refrigerant is mixed with non-condensable gases such as air and nitrogen. There is air in the refrigeration system. In many cases, the pointer of the high-pressure meter will vibrate severely when there is a lot of air.


Solution: This situation generally occurs after maintenance, and the vacuum is not complete. It can be evacuated at the highest point of the condenser after shutdown or re-evacuated to add refrigerant.


If your water chiller machine has a high-pressure alarm, you can check according to the article. Or you can contact the water chiller factory to help you solve it. Need to know the details of our water chiller machine, please visit the products page.


What is a water cooled chiller system?

2025-06-20

The water-cooled chiller system is an industrial cooling system composed of a water-cooled chiller, a water tank, a water pump, and a cooling tower. The water-cooled chiller is based on the cooling method of the condenser, which uses cooling water to take away the heat (cooling tower), rather than the fan to take away the heat, which is relative to the air-cooled chiller. Water-cooled chillers include Packaged water-cooled units, open-type water-cooled units, and screw-type chillers. The water-cooled chiller is composed of a compressor, an evaporator (the evaporator can be a water tank coil, a plate heat exchanger, or a shell and tube evaporator), a shell and tube condenser, an electric control part, and a water pump (can be external, not It is made on the chiller), and the water tank (generally, the box-type chiller will have a built-in water tank, and the open-type chiller or screw-type chiller will need an external water tank). Today we will talk about water-cooled screw chillers in detail. Generally, water-cooled chillers are mostly screw chillers.


water cooled screw chiller system


The water-cooled screw chiller system is composed of a water-cooled screw chiller, an external water tank, a water pump (the standard system requires 3 water pumps), and a cooling tower. The water-cooled screw chiller has four main components: screw compressor (hanbell screw compressor, Bitzer screw compressor, Refcomp Screw compressor Optional), shell-and-tube evaporator, shell-and-tube condenser, and a control system. Water-cooled chillers have many advantages.

1. The energy efficiency ratio of water-cooled chillers is higher than that of air-cooled chillers

2. Water-cooled chillers have stable performance

3. Water-cooled chiller saves electricity and energy

4. Water-cooled chillers have a long service life

5. Water-cooled chillers have a wide range of applications

6. The water-cooled chiller is small in size and occupies a small area.


The water-cooled cooling water system requires the guidance of a professional engineer during installation due to the large number of pipelines that need to be connected. Omar will provide professional drawings to guide customer installation. If you have any questions when purchasing a water-cooled chiller system, please contact us. Email: oumal@oumal.com.


What is the difference between an air-cooled screw chiller and a water-cooled screw chiller

2025-06-20

Both air-cooled screw chillers and water-cooled screw chillers use semi-hermetic screw compressors, and screw compressors have a high energy efficiency ratio. At present, the compressors of screw-type industrial chillers mostly use compressor brands such as Hanbell Bitzer, Fusheng, and Refcomp and other compressor brands. The main difference between the air-cooled screw chiller and the water-cooled screw chiller is the form of heat dissipation. The air-cooled screw chiller uses a fan to dissipate heat, uses air as the cooling medium, and dissipates heat through the air through a fin condenser and a low-noise fan. To cool the refrigerant, the water-cooled chiller uses water as the cooling medium, and then the cooling water cools the refrigerant.


Secondly, the installation of the air-cooled screw chiller is simple and does not require a cooling tower. Because the screw chiller machine is relatively large, an external water tank is used. The air-cooled screw chiller is greatly affected by the ambient temperature, especially in some areas with high ambient temperature, which will cause poor cooling effect and may cause a high-pressure alarm due to excessive temperature. As the air-cooled screw chiller’s water quality requirements are small, so we recommend installing an air-cooled screw chiller where the water quality is not good. The water-cooled screw chiller is not affected by the environment, and the cooling effect is better than the air-cooled screw chiller. In the case of the same cooling capacity, due to the lower condensing temperature of the water-cooled screw chiller, higher cooling effect, lower power and lower power consumption, the operating cost of the water-cooled screw chiller is lower than that of the air-cooled screw chiller machine.


Therefore, when purchasing a screw chiller, whether to choose an air-cooled screw chiller or a water-cooled screw chiller requires us to consider the environment, installation, and cost. If you are still hesitating about how to choose a chiller, contact us and a professional refrigeration engineer will give you advice. Email: oumal@oumal.com.


air-cooled screw chiller vs water-cooled screw chiller

What should I do if the chilled water of the industrial chiller does not circulate?

2025-06-20

In the process of using the chiller, have you encountered the problem that the chilled water of the chiller does not circulate? How to solve the problem of the chilled water not circulating?


We all know that under normal circumstances, small industrial chillers have been equipped with chilled water circulation pumps, such as Packaged air-cooled chillers, box-type water-cooled chillers, and large capacity chillers such as screw chillers and open-type water chillers. The chiller does not contain a chilled water circulating pump. At this time, when installing the cooling water system, an external chilled water circulation pump must be installed, so that the cooling water returns to the chiller for cooling after absorbing the heat of the cooling equipment, so that the cooling water supply pipe forms a circulation system.


It should be noted that no matter whether the chilled water pump is inside the built-in chiller case or outside the chiller, it is recommended that the location of the chilled water pump should be lower than the water level of the water tank. In this way, the circulating water pump can absorb cooling water well. However, in some cases, due to the needs or limitations of the installation environment, the chilled water pump may be higher than the water level of the water tank, so that the cooling water system cannot absorb water during operation, resulting in the chiller. In the case of insufficient chilled water flow, it cannot be started and a fault is reported. So what should we do when the chiller fault code shows insufficient chilled water flow?




1. Use a rubber tube (open its small valve) to send back the water supply pipe reserved on the large pipe on the water tank, and use a wrench to unscrew the vent plug of the cold water circulation pump (if there is water before tightening), until the water is removed. Return to the large tube in the tank and pull the hose out to see if any air bubbles come out. If it does, keep pouring water into the tank until the return water returns to the large pipe in the tank, then unplug the hose and see if any air bubbles come out. If yes, keep pouring water. Close the small valve until there are no air bubbles.


2. At this point, turn on the chiller for 1 minute. If the big pipe has a lot of water back into the pool, that's fine.


3. If the return water is not enough or there is no return water, repeat the above irrigation operation.


When you purchase and install the Oumal industrial chiller, if the chilled water flow is insufficient during the installation test, please contact our sales in time, we will arrange a professional engineer to guide you to solve the problem. Tel: +86 15112554736.


Why is the sand mill need to be equipped with a chiller?

2025-06-20

Sand mill, also known as laboratory bead mill, or nano sand mill, is mainly used for wet grinding of chemical liquid products. It is mainly composed of body, grinding cylinder, sand grinding disc (lever), grinding medium, motor and feeding pump. The speed of feeding is controlled by the feeding pump. The grinding media of this equipment are generally divided into zirconia beads, glass beads, zirconium silicate beads, etc.

 

Since the sand mill (bead mill) is working, the material and the grinding medium will have strong collision and friction, which will generate a lot of heat energy, and the grinding inside of the sand mill should generally not exceed 65 degrees. The machine protection temperature will cause the temperature switch to act, and the sand mill will automatically stop for protection, thus affecting the production efficiency. Inversely, if the internal temperature of the grinding is too low, the viscosity of the grinding slurry will be too high, the action motor cannot be driven, and the grinding motor may be burned. It can be seen that the sand mill must match the cooling system.

The functions of the Oumal sand mill chiller system in the sand grinding process are as follows:

 

1. Effective control of slurry dehydration. Most of the energy consumed by grinding is converted into heat energy, which increases the temperature of the air and material. For ball mills, the high temperature inside the grinding chamber will lead to dehydration of the slurry, which will adversely affect the setting time and strength of the slurry. Oumal sand grinding cooling system can avoid this phenomenon.

 

2. During the sanding process, the surface of the slurry absorbs a part of the air to form an air film, which hinders the electrostatic interaction between the particles and avoids the adsorption and condensation on the surface of the particles. However, when the temperature exceeds 100 °C, the air film adsorbed on the surface of the particles is destroyed, and adsorption and coalescence are formed between the particles and the particles, and between the particles and the lining plate of the grinding body under the electrostatic action, which plays a buffering role in the grinding. Reduced grinding efficiency. This effect increases with the increase of the specific surface area of the product and the increase of the temperature in the mill. Therefore, water cooling system can improve the grinding efficiency.

 

3. When grinding cement, the material entering the grinding temperature is generally higher than the material entering the grinding temperature when grinding raw meal, and the product fineness is also relatively fine. Therefore, the temperature inside the mill is higher. If it is not cooled, the temperature of the cylinder body is too high, on the one hand, the gap between the lining plates will become smaller due to thermal expansion. In severe cases, the lining plate will be squeezed together to bulge and the lining plate screws will be broken. On the other hand, the temperature of the cylinder body will also be conducted. To the hollow shaft, the temperature of the hollow shaft is too high and equipment accidents are caused. Therefore, water chiller systems will improve the safe operation of the equipment.

 

Oumal Chiller specializes in the production and processing of various specifications and models of industrial chillers, which can be used for cooling and cooling of grinding equipment such as sand mills, bead mills, and grinders. downtime. The chiller is compact in structure, easy to move, high efficiency, low noise, power saving and durable. It can effectively control the temperature of the sand mill to ensure that the material temperature and material do not deteriorate. It is a kind of matching refrigeration equipment that can prevent high temperature during the operation of the sand mill equipment and keep the equipment within a certain cooling temperature range through continuous water circulation. normal operation of the sand mill.

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