Freeze dryer Freeze dryer training materials Basic knowledge of air Ø What is air? What is wet air The atmosphere around the earth, we are used to call it air. The air in nature is made up of multiple gases (O2, N2, CO2 .......)), Steam is one of them. The air with a certain amount of water vapor is called wet air, and the air without water vapor is called dry air. The air around us is humid air. The composition and proportion of dry air below a certain altitude are basically stable, and it has no special significance for the thermal performance of the entire humid air. Although the water vapor content in the humid air is not large, the change of the content has a great influence on the physical properties of the humid air. The content of the water vapor determines the dryness and humidity of the air. The working object of the cold dryer, adsorption type and desiccant dryer is humid air.
Ø What is saturated air?
Under certain temperature and pressure conditions, the content of water vapor (ie, water vapor density) in the humid air is limited; at a certain temperature, when the amount of water vapor contained reaches the maximum possible content, the humidity at this time The air is called saturated air. Moist air when the water vapor does not reach the maximum possible content is called unsaturated air.
Ø Under what conditions does unsaturated air become saturated air? What is condensation?
Under the condition of constant water content, it can be made saturated air by reducing the temperature of unsaturated air. When the unsaturated air becomes saturated air, there will be liquid water droplets condensing out in the humid air, this phenomenon is called "condensation" (the working principle of the cold dryer)
Ø What is atmospheric pressure? What is absolute pressure? What is gauge pressure?
The pressure caused by a thick atmosphere surrounding the earth's surface on the earth's surface or surface objects is called "atmospheric pressure", and the pressure directly acting on the surface of the container or object is called "absolute pressure". The absolute pressure value is absolute vacuum. The starting point, the pressure measured with pressure gauges, vacuum gauges, U-shaped tubes and other instruments is called "gauge pressure" (also called relative pressure) "gauge pressure" starts at atmospheric pressure.
The relationship between the three is: gauge pressure = absolute pressure + atmospheric pressure (for pressure units, please refer to the unit conversion table)
Ø What is the standard state of air?
The air state at a temperature of 20 ° C, an absolute pressure of 10 bar, and a relative temperature of 65% is called the standard state of air. Under the standard state, the air density is 1.2 kg / cm3 (after the air compressor exhaust, dryer, filter, etc. The processing capacity of the processing equipment is marked by the flow rate in the standard air state, and the unit is recorded as Nm3 / min.
Ø What is compressed air? What are the characteristics?
The air is compressible. The mechanical work of the air compressor reduces its volume. The air with increased pressure is called compressed air. Compressed air is an important power source. Compared with other energy sources, it is easy to transport and easy to use. Compressed air mainly comes from the ground atmosphere, so it is easy to take and inexhaustible.
Ø The conversion equation between compressed air state and standard state?
The compressed air state and the standard state can be converted by the state equation. There are many conversion methods. The simplified one is P1 * V1 / T1 = P0 * V0 / T0. In the formula, P is the absolute pressure of the gas (Pa), and V is The specific volume of the gas (m3 / kg), T is the temperature of the gas (K), and the index 0 represents the parameters in the compressed state, and the ones with the 1 are the parameters in the compressed state. Because the temperature of the air before and after pressurization is constant, the volume of air after pressurization can be calculated using the equation of state, the calculation formula is V1 = P0 * V0 / P1
Ø What impurities are contained in compressed air?
The compressed air discharged from the air compressor contains many impurities: water (including water mist, water vapor, condensed water), oil (including oil dirt, oil vapor), solid matter (including rust mud, metal powder, tar particles, sealing material) The details are not waiting), in addition to a variety of harmful chemical odor substances.
Ø What is a gas source system?
The system composed of equipment that generates and processes compressed air is called an air source system. A typical air source system is composed of the following parts: air compressor, rear cooler, filter (including pre-filter, post-filter), air storage tank, dryer (refrigerated or adsorption), automatic Sewage traps, gas pipelines, pipeline valves, instruments, etc. The above equipment is combined into a complete gas source system according to the different needs of the process flow.
Ø Why must the compressed air be processed?
The compressed air output from the air compressor contains a lot of harmful impurities. Failure to remove these impurities through appropriate methods will cause great harm to the air supply system. Water will cause rust and corrosion of metal devices and pipelines, causing moving parts to become stuck or Wear, make the pneumatic components malfunction or leak. Deteriorated oil will deteriorate rubber, plastics, sealing materials, or contaminate the product, resulting in poor product quality. Solid matter can block the orifice or filter, causing malfunction of the valve or speeding up the wear. Due to poor air quality, the reliability and service life of the pneumatic system are greatly reduced, and the resulting losses often exceed the cost and maintenance costs of the air source treatment device, so the correct selection of the air source treatment system is absolutely necessary.
Ø How to remove impurities in compressed air?
In practical applications, the water in the gas source system is generally removed by pressurization, temperature reduction, adsorption and other methods, and the liquid moisture is removed by mechanical methods. The method of removing oil and impurities and odors is generally filtered by a filter.
Ø Quality standard of purified air The water content in the quality of the air source is measured by the dew point temperature, the oil is measured according to the content of the oil after purification, and the impurities are mainly measured according to the size of the particle size after purification.
Ø What is dew point and what is it related to?
Unsaturated air lowers the temperature while keeping the absolute water content constant, so that the temperature when it reaches saturation is called "dew point". When the temperature drops to the dew point, the condensed water drops out in the moist air. The dew point of the moist air is not only related to the temperature, but also to the moisture content in the moist air. The dew point with large water content is high, and the dew point with low water content is low.
Ø What is pressure dew point?
When the humid air is compressed, the water vapor density increases and the temperature also rises. When the compressed air cools, the relative humidity increases. When the temperature continues to drop to 100% relative humidity, water droplets will precipitate out of the compressed air. The temperature at this time is the pressure dew point temperature of the compressed air.
Functions of main accessories of freeze dryers Ø What are the commonly used freeze dryers?
Commonly used cold dryers are divided into air-cooled type and water-cooled type according to the cooling method of the condenser; according to the intake air temperature, there are high-temperature intake type (below 80 ℃) and normal temperature intake type (about 40 ℃); according to work The pressure is divided into ordinary type (0.3-1.0Mpa) and medium and high pressure type (above 1.2Mpa). In addition, many special specifications of the dryer can be used to process non-air media, such as: carbon dioxide, hydrogen, natural gas, blast furnace gas, nitrogen, etc.
Ø What are the technical parameters of the cold dryer?
The technical parameters of the dryer are: treatment capacity (Nm3 / min), intake air temperature (℃), working pressure (Mpa), pressure drop (Mpa), compressor power (Kw), cooling water consumption (t / h).
Ø How does the dryer work?
For details, see Annex Ø What role does the heat exchanger play in the dryer?
Strictly speaking, the heat exchanger is not an indispensable part of the freeze dryer, but it plays a big role in the operation of the cold dryer. The main function of heat exchange in the cold dryer is to use the cold capacity carried by the compressed air cooled by the evaporator (for most users, this part of the cold capacity is waste cold) and use this part of the cold capacity to cool and carry a lot of The higher temperature compressed air of water vapor reduces the heat load of the refrigeration system of the dryer, so as to save energy. On the other hand, the temperature of the low-temperature compressed air is increased in the heat exchanger, so that the outer wall of the exhaust pipe does not cause condensation due to the low temperature. In addition, the temperature of the compressed air increases, reducing the relative humidity of the air in the pipeline (up to 5-10%). According to the theory of metal corrosion, when the relative humidity of the environment is lower than the critical point (40%), the rust phenomenon on the metal pipes will stop, so now the cold dryers are equipped with heat exchangers.
Ø What is the role of the secondary condenser?
The secondary condenser has the same function as the heat exchange on the machine. The difference between the two is that the heat exchanger is mainly the heat exchange of high temperature and low temperature compressed air, and the secondary condensation mainly uses low temperature compressed air and the high pressure part of the refrigeration system for cooling , To achieve adequate cooling of the refrigerant, thereby improving the cooling efficiency of the machine, and at the same time avoiding high-pressure trips or machine failures caused by poor heat dissipation of the machine condenser.
Ø What is the role of the evaporator in the cold dryer?
The evaporator is the main heat exchange part of the cold dryer. The compressed air is forcedly cooled in the evaporator. Most of the water vapor is cooled and condensed into liquid water to be discharged outside the machine, thereby drying the compressed air. What is carried out in the evaporator is convective heat and mass exchange between the air and the low-pressure refrigerant vapor. The low-pressure refrigerant liquid after passing through the throttling device changes into a low-pressure refrigerant vapor in the evaporator, absorbing the surrounding heat during the phase change process. This cools the compressed air.
Ø What role does the condenser play in the cold dryer, and what kinds of forms are there?
The role of the condenser in the cold dryer is to cool the high-pressure and superheated refrigerant vapor discharged from the refrigerant compressor into a liquid refrigerant, so that the refrigeration process can be continued continuously. The heat discharged from the condenser includes the heat absorbed by the refrigerant from the evaporator and the heat converted from the work of compression. Therefore, the load of the condenser is greater than that of the evaporator. There are two types of condensers in the air dryer: air-cooled (air-cooled condenser) and water-cooled (water-cooled condenser).
Ø What role does the hot gas bypass valve play in the cold dryer?
When the compressed air is cooled in the evaporator, a large amount of condensed water is deposited. If the refrigerant evaporation temperature is too low, and the surface temperature of the copper tube of the evaporator is lower than the freezing point of the water under load, the condensed water will freeze in the evaporator, which will block the air flow channel and paralyze the air supply pipeline. In order to prevent this from happening, the refrigerant evaporation temperature must be controlled. The simple and effective measure is to add a hot gas bypass valve between the condenser and the evaporator, and the pressure measuring pipe of the hot gas bypass valve is directly connected to the evaporation pressure. When the evaporation pressure is lower than a certain level, the hot gas bypass valve opens, and the high-temperature refrigerant vapor in the condenser directly enters the evaporator to increase the evaporation temperature and avoid ice blocking.
Ø What role do thermal expansion valves or capillaries play in the refrigeration system?
The expansion valve (capillary) is the throttling mechanism of the refrigeration system. In the cold dryer, the supply of evaporator refrigerant and its regulator are achieved through the throttle mechanism. The throttling mechanism allows refrigeration to enter the evaporator from the high-temperature and high-pressure liquid.
When the load changes, the thermal expansion valve detects the intake air superheat temperature of the compressor to adjust the opening of the valve core, thereby controlling the amount of refrigerant supplied into the evaporator. The capillary tube has the characteristic of self-compensation, that is, when the evaporation pressure decreases, the pressure difference between the two ends will increase accordingly, thereby increasing the amount of refrigerant flowing into the evaporator. Due to its simple structure and stable operation, the capillary tube is widely used in small cold dryers.
Ø What role does the filter drier play?
In the running refrigeration device, due to the presence of impurities such as moisture, solid powder, and dirt in the refrigerant and freezing oil, the throttle hole of the throttle structure will be dirty and clogged when the situation is serious. Therefore, a filter drier must be installed before the refrigerant supply pipe. In addition, trace moisture in the refrigerant is the most harmful to the refrigeration system. It is extremely important to dry the refrigerant, freezing oil, evaporator, condenser and piping.
Ø What are the characteristics of refrigeration compression for cold dryer?
Most of the refrigeration compressors used in the dryer are medium-high temperature fully-sealed reciprocating compressors, which are characterized by compact structure, small volume, light weight, low vibration, low noise, and high energy efficiency ratio. Since the motor of the hermetically sealed compressor and the compressor body are sealed in a steel casing, the motor operates in a refrigerant gaseous environment, with better cooling conditions and longer life. There is a prescribed amount of lubricating oil in the lower part of the casing. When the compressor is working, oil is automatically supplied to each part, and no additional lubricating oil is needed.
In large-scale cold and dry machines, semi-sealed reciprocating machines or screw compressors are also used. They are characterized by large cooling power and can be adjusted to meet different needs.
Ø What is the working principle of cyclone gas-water separator?
The cyclone separator is also an inertial separator, which is mostly used for gas-solid separation. After the compressed air enters the separator along the tangential direction of the cylinder wall, it rotates inside, and the water droplets mixed in the gas also rotate together and generate centrifugal force. The centrifugal force generated by the large-mass water droplets is large. After touching the outer wall (also the baffle), it gathers and grows up and separates from the gas.
Ø How does the auto drain work?
When the water level in the water storage cup of the drain does not reach a certain height, the pressure of the compressed air will press the float down to close the drainage hole, and it will not cause airflow leakage: as the water level in the water storage cup rises (the cold dryer does not Water accumulation), when the float rises to a certain height, the drainage hole is opened, and the condensed water in the cup is quickly discharged out of the machine under the action of air pressure. After the condensate is drained, the float closes the drain hole under the action of air pressure. Therefore, the automatic drain is an energy-saving device. It is not only used in cold dryers, but also widely used in various gas source treatment equipment such as gas storage tanks, after coolers and filters.
In addition to the commonly used float-type automatic drains, electronic automatic drains are often used. The time of this drain and the time interval between two drains can be adjusted, and it can withstand higher pressures and is also widely used.
Basic knowledge of freeze dryer design Ø Why do you need fins on the outer edge of the evaporator and heat exchanger copper tubes?
In order to obtain a higher heat transfer effect as much as possible, it is necessary to increase the heat release coefficient, that is, the heat exchange area of ​​the heat exchanger. Therefore, the outer wall of the copper tube of the evaporator and heat exchanger of the cold and dry machine adopts a set of aluminum fins. . At the same time, the fins on the copper tube of the heat exchanger can reduce the impact of the air on the copper tube and prevent the copper tube from breaking.
Ø Why can't the evaporation temperature of the cold dryer be very low?
Under normal circumstances, there is a film of condensate on the surface of the evaporator. If the temperature of the evaporator drops very low, the surface temperature of the heat exchange copper tube is below zero, and the water vapor will condense on the surface of the copper tube to form frost. The problem caused by this is that the water vapor sublimation cream absorbs about 15% more cooling capacity than condensed dew, which reduces the processing capacity of the main machine; the thermal conductivity of the other cream is only 1/4 of the water, so that the air outside the tube cannot Fully cooled, and at the same time the evaporation temperature in the tube has a tendency to further decrease. The result of such a cycle will inevitably bring many adverse consequences to the refrigeration system such as liquid compression; and the presence of frost will increase the air resistance and reduce the air supply pressure. In severe cases, it may even block the gas path.
Ø How to control the refrigerant evaporation pressure of the dryer?
The refrigerant evaporation pressure is an important parameter for the normal operation of the refrigeration equipment. If the evaporation pressure is high and the evaporation temperature is high, the compressed air will not reach the proper cooling temperature, resulting in an excessively high dew point temperature. If the evaporating temperature is too low, the cooling capacity of the compressor is reduced, which also affects the dew point of the compressed air, and it is easy to cause liquid compression accidents. Therefore, the evaporation temperature must be controlled within a reasonable range.
Air-cooled dryers use a pressure controller to detect the refrigerant evaporation pressure (or condensation pressure), turn on the fan when the pressure reaches a certain upper limit, and force the condenser to ventilate and cool, and limit the refrigerant low pressure rise by reducing the refrigerant high pressure ; When the pressure is lower than this set lower limit, the fan stops, so that the refrigerant evaporation pressure will not drop too low.
The water-cooled dryer is controlled by the opening degree of the automatic water volume control valve to control the amount of cooling water and keep the condensing pressure at a normal value.
Ø How is the compressed air and condensed water separated?
The cold dryer is the process of condensate generation and steam-water separation, which starts after the compressed air enters the cold dryer. After the baffle is installed in the heat exchange and evaporator, this steam-water separation process becomes more intense. After colliding with the baffle plate, the condensed water droplets accumulate and grow up due to the combined effects of movement change, inertial gravity, etc., and finally realize the separation of steam and water under the action of their own gravity. In order to capture some of the small water droplets remaining in the air, a more efficient proprietary air-water separator is also installed in the dryer to minimize the liquid water entering the exhaust pipe, thereby reducing the "dew point" of the compressed air as much as possible. ".
Ø What is the significance of timely drainage of condensate to the cold dryer?
When the dryer is working, a lot of condensate will accumulate in the heat exchanger and the evaporator container. If the condensate is not discharged in time and completely. The cold dryer becomes a water reservoir. The result: a large amount of liquid water is entrained in the exhaust gas, which makes the work of the dryer less meaningful; the liquid water in the machine must absorb a large amount of cold, which increases the load of the dryer; the compressed air circulation area becomes smaller, and the air pressure drop increases, Therefore, the condensate in the dryer is promptly and completely discharged from the machine. It is an important guarantee for the normal operation of the cold dryer.
Ø Why should I use automatic drain in the dryer?
In order to drain the condensate of the dryer in a timely and complete way, the simplest method is to open a drain hole at the end of the evaporator, which can continuously discharge the condensate water generated in the machine. But its disadvantages are also obvious. Because the compressed air is continuously discharged while draining. Make the compressed air pressure drop quickly. This is not allowed for the gas source system. Although manual timing drainage by hand valve is feasible, it needs to increase manpower and a series of management troubles caused thereby. Using an automatic drain, it can automatically drain water in the machine regularly (quantitatively).
Ø What kind of refrigerant is currently used in domestic refrigeration dryers? What are the characteristics?
At present, most of the domestic freeze dryers use R22 as the refrigerant. Its characteristics are: non-flammable, non-explosive, colorless, odorless, low toxicity, is a safe refrigerant; R22 unit volume cooling capacity is nearly 50% larger than R12 and its replacement R134a; R22 is slightly different from lubricating oil Melted. They are mutually soluble in the compressor crankcase and condenser. Separated again in the evaporator. R22 will produce acid in the presence of trace moisture, which will slowly corrode metals. Therefore, it is necessary to prevent the water from entering the system when the refrigerant is injected and the freezing oil is added.
Ø What factors do the load of the cold dryer depend on?
The load of the cold dryer depends on the water content of the compressed air being processed. The more water content, the higher the load. Therefore, in addition to the work load of the dryer is directly related to the compressed flow rate (Nm3 / min), the parameters that have the most influence on the load of the dryer are: 1 intake air temperature: the higher the temperature, the more the air moisture content More, the load of the dryer is higher; 2 Working pressure: under the same temperature conditions, the lower the saturated air pressure, the more water content, the higher the load of the dryer. In addition, the relative humidity in the suction environment of the air compressor also has a relationship with the saturated water content of the compressed air, so it also affects the work load of the cold and dry machine: the greater the relative humidity, the more water content in the saturated compressed gas, the cold and dry The higher the aircraft load.
Ø What should I do if the exhaust temperature of the cold dryer is very low?
In a particular industry, not only compressed air with a very low pressure dew point (water content) but also compressed air must be kept at a low temperature, that is, the cold dryer should be used as a "dehydration cooler". The measures taken at this time are: accounting for the refrigeration system at the same time, if necessary, increase the power of the compressor, the heat exchange area of ​​the evaporator and condenser, etc.
Ø What are the characteristics of air-cooled condenser?
The air-cooled condenser does not require cooling water, and is suitable for applications in areas with difficult water supply or mobile occasions. However, its heat transfer effect is worse than that of water-cooled type. When it is used in high temperature or poorly ventilated environment, the condensation pressure is not easy to drop. When used in a dusty environment (such as cement plant, flour mill, textile mill, etc.), the surface of the condenser is prone to dust and scale, which affects heat transfer, so it is generally only suitable for small and medium-sized cold dryers.
Ø Can the cold dryer exclude water vapor in other gases?
The cold dryer uses the principle of water vapor encountering cold condensation to dry compressed air, and of course can be used to remove water vapor from other gases. When the cold dryer is used as a non-air dewatering and drying equipment, it should have an understanding of the physical and chemical properties of the processed medium and take targeted technical measures. For example, when it is used to remove water from hydrogen, because hydrogen is an explosive gas, it is necessary to consider the explosion-proof measures as the first condition, such as the use of explosion-proof electrical appliances or split structure. If it is used for CO2 water removal, because the aqueous solution of CO2 is slightly acidic, it has a corrosive effect on the parts of the cold dryer. Therefore, all parts in contact with the gas are made of anti-corrosion structure or stainless steel. In addition, it is necessary to understand the other physical properties of the other gases being processed, such as strong specific heat, specific gravity, and partial pressure of water vapor. These parameters have a great influence on the heat load of the dryer, and the thermal calculation must be re-calculated to make the dryer work When not overloaded.
Basic knowledge of installation of refrigeration dryer Ø What should be paid attention to when using the dryer?
The following items should be noted when using the dryer: the flow pressure and temperature of the compressed air should be within the allowable value on the nameplate; the installation site should be ventilated, less dust, there is enough heat dissipation and maintenance space around the machine, and it cannot be installed outdoors to avoid rain and sunlight Direct shot; cold dryers are generally allowed to be installed without foundation, but the ground must be leveled; should be as close as possible to the gas point to avoid excessively long pipelines; there should be no detectable corrosive gases in the surrounding environment, especially pay attention not to coexist with ammonia refrigeration equipment One room; the filtering accuracy of the pre-filter of the cold dryer should be appropriate, too high precision is not necessary for the cold dryer; the cooling water inlet and outlet pipes should be set independently, especially the outlet pipe should not be shared with other water cooling equipment, to avoid the pressure difference caused Drainage is blocked; the automatic drain must be kept clear at all times; do not start the dryer continuously.
Ø What are the characteristics of the cold dryer compared with the adsorption dryer?
Compared with the adsorption dryer, the cold dryer has the following characteristics: no air source consumption, for most air source users, the use of the cold dryer saves energy compared to the adsorption dryer; no valve wear; no need Add and replace the adsorbent regularly; the operation noise is low; the daily maintenance is relatively simple, as long as the automatic drain filter is cleaned on time. There are no special requirements for the pretreatment of the air source and the supporting air compressor. The general oil-water separator can meet the requirements of the cold dryer on the intake quality; the cold dryer has a "self-cleaning" effect on the exhaust, that is, the exhaust The content of solid impurities in the gas is less; while draining the condensed water, part of the oil vapor can also be condensed into a liquid oil mist and discharged with the condensed water.
Compared with the adsorption dryer, the "pressure dew point" of the compressed air treatment of the cold dryer can only reach about 10 ℃, so the drying depth of the gas is far less than that of the adsorption dryer. In many applications, cold drying is used. The machine can not meet the dryness requirements of the gas source. A modeling convention has been formed in the technical world; when the "pressure dew point" requirement is above zero, the cold dryer is preferred; when the "pressure dew point" requirement is below zero, the adsorption dryer is the only choice.
Ø What should be paid attention to when installing air-cooled dryer?
Air-cooled dryers are not as effective as water-cooled dryers, so you should pay attention to the following points during installation: they should be installed in a ventilated place, and there should be no obstacles affecting the ventilation before and after the condenser; In order to avoid direct sunlight, which affects the heat transfer effect; in dusty occasions, a filter cover that is easy to clean but does not affect ventilation should be installed in front of the air inlet; there should be no heat source near the cold dryer, such as the air compressor exhaust Close together; when co-located with a typhoon cold dryer, the cold dryer should be arranged horizontally to avoid mutual influence.
Main points for daily maintenance of air-cooled dryers: often use an air spray gun to sweep the dust accumulation on the surface of the condenser; keep the automatic drain to drain smoothly.
Ø What are the requirements for cooling water and water quality of water-cooled condensers?
The water-cooling type dryer has better heat transfer effect than the air-cooling type, but it consumes a large amount of water and has the following requirements for water quality: the temperature of the water entering the dryer should be below 31 ℃, and the outlet temperature should not exceed 36 ℃; The pressure should be kept above 2bar to ensure smooth flow of water (but not too high, generally not higher than 6bar); there should be no visible solid debris in the water.
Ø What should be paid attention to when cooling water piping of water condenser?
Water-cooled dryers are often in the same room as other water-cooled equipment (such as air compressors). When cooling water piping, the dryer should have an independent drain outlet. If the drain pipe is shared with other water-cooled equipment, the return water may not be smooth due to the difference in water pressure. If a common drain pipe is necessary, try to avoid T-shaped connections or reverse-angle connections.
Ø What should I pay attention to when using the automatic drain?
The automatic drain of the dryer can be said to be the most prone to malfunction. The reason is that the condensate discharged from the dryer is not clean water, but a thick liquid mixed with solid impurities (dust, rust, etc.) and oil (so the automatic drain is also called "automatic drain valve"), which is extremely It is easy to block the drain hole. A filter screen is installed at the inlet of the automatic drain for this purpose. However, if it is used for a long time, the filter will be blocked by oil impurities. If it is not cleaned in time, the automatic drain will be useless. and so. It is important to clean the strainer in the drain at regular intervals.
In addition, the automatic drain must have this pressure to work. For example, the minimum working pressure of the commonly used AD-402 type automatic drain is 0.15Mpa. If the pressure is too low, air leakage will occur. But the pressure should not exceed the rated value to prevent bursting of the water storage cup. When the ambient temperature is below zero, drain the condensate in the water storage cup. To prevent freezing and cracking.
Ø What effect does the ambient temperature have on the operation of the dryer?
High ambient temperature is very detrimental to the heat dissipation of the refrigeration system of the dryer. When the ambient temperature is higher than the normal refrigerant condensation temperature, the refrigerant condensation pressure is forced to increase, which will cause the compressor cooling capacity to decrease, which eventually leads to the "pressure dew point" of compressed air Rise. Generally speaking. A lower ambient temperature is beneficial to the operation of the dryer, but in a too low environment (for example, below zero degrees Celsius), although the temperature of the compressed air entering the dryer is not low, the dew point of the compressed air will not be large. The change. However, when the condensate is discharged through the automatic drain, it is likely to freeze in the drain. This must be prevented. In addition, during shutdown, the condensed water originally accumulated in the evaporator of the cold dryer or the condensed water accumulated in the water storage cup of the automatic drain may freeze, and the cooling water accumulated in the condenser may also freeze. All of them cause damage to the relevant parts of the dryer.
The user should also pay attention to: "When the ambient temperature is lower than 2 ℃, the compressed air pipeline itself is equivalent to a well-operated cold dryer. At this time, it is necessary to pay attention to the treatment of condensate in the pipeline itself. Many manufacturers issued clearly stated in the manual of the cold dryer: when the temperature is lower than 2 ℃, do not use the cold dryer.
Ø In addition to the temperature, what requirements does the dryer have for the environmental conditions?
The influence of the ambient temperature on the work of the dryer is very large. In addition, the dryer has the following requirements on its surroundings: 1 ventilation, especially for the dryer of the air-cooled dryer; 2 dust Not too much; 3 There should be no direct radiation pyrogens in the use site of the cold dryer; 4 The air should not contain corrosive gas, especially ammonia gas cannot be detected. Because ammonia gas has strong corrosive effect on metallic copper in the presence of water. Therefore, the cold dryer should not be installed together with the ammonia refrigeration equipment.
Ø What measures should the cold dryer take when the intake air temperature is too high?
The intake air temperature is an important technical parameter of the dryer. All manufacturers have a clear limit on the upper limit of the intake air temperature of the dryer. Because the high intake air temperature not only means an increase in sensible heat, but also the water contained in the compressed air The vapor content also increased. When the inlet temperature of the cold dryer does not exceed 45 ℃, many well-known foreign manufacturers of cold dryers have similar regulations. It stands to reason that when the temperature of the air compressor exhaust exceeds 45 ° C, a rear cooler must be added downstream of the air compressor to reduce the temperature of the compressed air to the specified value before entering the post-processing equipment. Because in the normal temperature range, using the rear cooler to reduce the temperature of the compressed air is the most cost-effective way. The high-temperature air intake type cold dryer is to install the rear cooler on the cold dryer without changing the refrigeration system conditions. The effect is very obvious.
Ø What is the effect of too high oil mist content in compressed air on the operation of the dryer?
The exhaust oil content of the air compressor is different. For example, the exhaust oil content of the piston oil-lubricated air compressor is 65-220mg / m3, and the exhaust oil content of the low-oil lubricated air compressor is 30-40 mg. / m3, the so-called oil-free lubricated air compressor (actually semi-oil-free lubricated) also has an exhaust oil content of 6-15 mg / m3; sometimes, due to the failure of the oil and gas separator in the air compressor, the air compressor will The oil content in the air is greatly increased, and the compressed air with a large oil content will be covered with a thick oil film on the surface of the copper tube of the heat exchanger after entering the dryer, because the heat transfer resistance of the oil film is 40-70 larger than the copper tube This will greatly reduce the heat exchange performance of the pre-cooler and the evaporator. In severe cases, the dryer will not work properly. The specific performance is that the evaporating pressure drops, and even the constant replacement of the degreasing filter in the pipeline system of the cold dryer will not help. The filter element of the precision filter will soon be blocked by oil stains. The best way is to repair the air compressor and replace the filter element of the oil and gas separator to make the exhaust oil content reach the normal factory index.
Check items before operation and maintenance of the refrigerated dryer Ø Whether the power supply voltage, phase number, and frequency comply with the regulations (please refer to the nameplate), and whether the power cord is firmly connected.
Ø Whether the connection part of each piping of the system is locked.
Ø Check whether the cooling system pressure of the machine is normal. (When the pressure gauge indicates less than 0.2Mpa, please notify my dealer or our service department)
Ø Whether the dryer is placed properly and whether the ambient temperature meets the requirements for use.
Ø Check whether the ball valve at the front of the automatic drain valve is open.
Ø Whether the inlet temperature of the dryer exceeds the specified value.
Ø In order to better improve the air quality, please start the dryer and make it run smoothly before using the compressed air. When closing, please turn off the compressed air first and then turn off the dryer, and evacuate the compressed air in the air pipeline, so as not to affect the air quality due to poor drying or residual moisture in the pipeline.
Startup and operation Ø Send the power supply to the control box, press the ON button of the ON / OFF button switch, the operation indicator light indicates, the machine contactor is closed, and the compressor runs. At this time, the pointer of the refrigerant low-pressure meter should indicate within the range of 60 ~ 85Psig. If the load exceeds this range, please adjust according to "Evaporation Pressure Adjustment".
Ø After the compressor runs smoothly, the pressure of the refrigerant high pressure gauge rises to between 120 ~ 240Psig. When the high-pressure refrigerant pressure is higher than this range, please check whether the heat dissipation of the condenser is good, the inlet temperature of the air compressor and the ambient temperature are too high. When the antifreeze switch below 140Psig is activated, the condensing fan stops to increase the pressure to ensure the normal operation of the machine. If the machine is running under low pressure for a long time, please check whether the refrigeration system leaks and whether the ambient temperature is too low.
Ø In order to avoid compressor damage due to frequent starting. It takes more than three minutes to restart after shutdown.
Ø The valve on the machine has been adjusted before leaving the factory. If you are not a professional, please do not adjust it to avoid unnecessary damage to the machine.
Stop of the machine Ø Please turn off the air compressor before shutting down.
Ø Turn off the air compressor and press the ON / OFF switch to turn off the machine. Ø Turn off the power of the machine.
Commissioning of the machine (adjustment of evaporation pressure)
Ø Adjust the hot gas bypass valve as follows when the low-pressure deviation of the refrigerant is normal after the machine starts to run smoothly.
Ø When using R-22 refrigerant, the evaporation pressure is lower than 60psig, use a hex wrench to adjust the hot gas bypass valve clockwise to make the hot gas enter the system, and the evaporation temperature is higher. When it is higher than 85psig, use a hex wrench to adjust the hot gas bypass valve counterclockwise to reduce the evaporation temperature.
Ø When using R-12 refrigerant, the evaporation pressure range is between 25 ~ 45 psig. When it is lower than 25 psig or higher than 45 psig, the hot gas bypass valve should be adjusted. The adjustment method is the same as the R-22 system.
Ø Before adjusting the bypass valve, check whether the load of the machine is too large, whether the ambient temperature and inlet temperature are too high, and whether the condenser is dirty and blocked. If the normal value cannot be reached after adjustment, please contact our dealer.
Ø The evaporating pressure has been adjusted before leaving the factory. Please do not adjust if there is no change in pressure.
Failure Analysis of Freeze Dryer Ø What is the reason for the excessively high condensing pressure?
When the dryer is working, the condensing pressure of R-22 should be no more than 18bar. In practice, it is seen when the condensing pressure exceeds the situation. The problems that cause the condensing pressure to rise mainly include the following points: wind condenser condensing pressure The reasons are too high; the ambient temperature is too high or the ventilation is poor; the surface area of ​​the condenser has dust and dirt; the load of the dryer is too large; the air intrudes into the refrigerant system; the heat transfer area of ​​the condenser is not enough; the cooling fan air volume is small; the installation position of the dryerä¸å¯¹ï¼ˆå¦‚接近çƒæºã€è¢«å¤ªé˜³ç›´æ™’ã€å†·å¹²æœºå‰åŽæŽ’列间è·å¤ªè¿‘ç‰ï¼‰ï¼›æŽ§åˆ¶é£Žæ‰‡çš„压力开关设定ä¸å½“或æŸåï¼›å†·åª’é€šè·¯æˆ–å…ƒä»¶æœ‰å µå¡žçŽ°è±¡ï¼›å†·åª’å……æ³¨è¿‡å¤šï¼Œä½¿ä¼ çƒé¢ç§¯å‡å°ã€‚
水冷å‡å™¨å†·å‡åŽ‹åŠ›è¿‡é«˜çš„åŽŸå› æœ‰ï¼šå†·å´æ°´é‡ä¸å¤Ÿï¼Œæ°´æ¸©è¿‡é«˜ï¼›å†·å‡å™¨ä¼ çƒé¢ç§¯å°ï¼›ç©ºæ°”ä¾µå…¥å†·åª’ç³»ç»Ÿï¼ˆé“œç®¡ç ´è£‚ï¼‰ï¼›å†·å‡å™¨å£³ä½“容积å°ï¼Œå†…å˜å†·åª’æ¶²ä½“ä½¿æœ‰æ•ˆä¼ çƒé¢ç§¯å‡å°æˆ–冷媒充注过é‡ï¼Œæ°´å†·å‡å™¨ä½¿ç”¨æ—¥ä¹…，铜管水侧表é¢ç§¯åž¢ï¼›è‡ªåŠ¨æ°´é‡è°ƒèŠ‚阀开å¯åº¦å°æˆ–æŸå；冷冻油进入制冷系统；冷å´æ°´ç®¡é…管ä¸åˆç†ï¼Œé€ æˆå†·å´æ°´å›žæ°´ä¸ç•…；冷媒通路或元件（干燥过滤器ã€æ¯›ç»†ç®¡ç‰ï¼‰æœ‰å µå¡žçŽ°è±¡ï¼›å†·å¹²æœºè´Ÿè·å¤ªå¤§ï¼Œä½¿è’¸å‘压力å‡é«˜ï¼Œæ‹‰é«˜å†·å‡åŽ‹åŠ›ã€‚
Ø 冷å‡åŽ‹åŠ›è¿‡ä½Žæ˜¯ä»€ä¹ˆåŽŸå› ？
冷å‡å™¨å†·å‡åŽ‹åŠ›è¿‡ä½Žçš„åŽŸå› æœ‰å†·å´æ°´é‡å¤ªå¤šæˆ–水温太低；环境温度过低；控制风扇的压力开关或控制冷å´æ°´çš„自动水é‡è°ƒèŠ‚阀设定ä¸å½“或æŸå；冷媒充注é‡å¤ªå°‘；冷媒管路或元件有泄æ¼ç‚¹ï¼›å†·å¹²æœºè´Ÿè·å¤ªå°ã€‚一般冷å‡åŽ‹åŠ›ç¨ä½Žå¯¹å†·å¹²æœºå’Œåˆ¶å†·ç³»ç»Ÿè¿è¡Œæ— 大的影å“，但冷å‡åŽ‹åŠ›è¿‡ä½Žæœ‰æ—¶ä¼šå¯¼è‡´è’¸å‘压力下é™ï¼Œä½¿è’¸å‘器内结霜甚至出现液压缩，这是需è¦é˜²æ¢çš„。
Ø 冷媒çŒæ³¨é‡çš„多少对冷干机有何影å“？
冷媒çŒæ³¨è¿‡å°‘，冷干机会出现下列现象：蒸å‘压力ã€å†·å‡åŽ‹åŠ›éƒ½æ¯”æ£å¸¸è¿è½¬ä½Žï¼Œä½†ç©ºæ°”露点å´é™ä¸ä¸‹åŽ»ï¼›åŽ‹ç¼©æœºå¤–壳å‘烫。冷媒çŒæ³¨è¿‡å¤šï¼Œå†·å¹²æœºä¼šå‡ºçŽ°ï¼šç”±äºŽå†·åª’液体å˜ç§¯äºŽå†·å‡å™¨ï¼Œä½¿å†·å‡å™¨é¢ç§¯å‡å°ï¼Œå¯¼è‡´å†·å‡åŽ‹åŠ›å‡é«˜ï¼Œä¸¥é‡æ—¶å¼•èµ·é«˜åŽ‹è·³è„±ï¼›åˆ¶å†·åŽ‹ç¼©æœºè´Ÿè·å¢žé«˜ï¼Œèµ·åŠ¨å›°éš¾ï¼›åˆ¶å†·å‰‚在蒸å‘器ä¸æœªèƒ½å…¨éƒ¨æ±½åŒ–，使湿蒸气进入压缩机。有“液压缩â€å±é™©ï¼›ç”±äºŽå†·å‡åŽ‹åŠ›å‡é«˜ï¼Œä½¿åŽ‹ç¼©æœºåˆ¶å†·é‡å‡å°‘空气露点上å‡ã€‚
Ø 冷干机排气带水一定是露点ä¸å¤Ÿå¼•èµ·çš„å—？
压缩空气干燥度指的是在于压缩空气是混æ‚的水蒸气å«é‡çš„多少，水蒸气å«é‡å°‘，空气就干燥，å之就潮湿。压缩空气干燥度用“压力露点â€é«˜ä½Žæ¥è¡¡é‡ï¼Œâ€œåŽ‹åŠ›éœ²ç‚¹â€ä½Žï¼ŒåŽ‹ç¼©ç©ºæ°”就干燥。有时从冷干机排出的压缩空气ä¸ä¼šæ··æ‚有少é‡æ¶²æ€æ°´æ»´ï¼Œä½†è¿™å¹¶ä¸ä¸€å®šæ˜¯åŽ‹ç¼©ç©ºæ°”露点ä¸å¤Ÿé€ æˆçš„。排气ä¸æ¶²æ€æ°´æ»´çš„å˜åœ¨ï¼Œå¯èƒ½æ˜¯ç”±äºŽæœºå†…积水ã€æŽ’æ°´ä¸ç•…或分离ä¸å…¨å¼•èµ·çš„ï¼Œå°¤å…¶æ˜¯è‡ªåŠ¨æŽ’æ°´å™¨å µå¡žå¼•èµ·çš„æ•…éšœå½±å“最大。冷干机排气带水比露点ä¸å¤Ÿç»™ä¸‹æ¸¸ç”¨æ°”设备带æ¥æ›´åçš„ä¸åˆ©å½±å“ã€‚åº”æ‰¾å‡ºåŽŸå› äºˆä»¥æ¶ˆé™¤ã€‚
机å°çš„ä¿å…»å¯¹æœºå°è¿›è¡Œä¿å…»å’Œç»´æŠ¤æ˜¯ä¸ºäº†ä¿è¯æœºå°æ£å¸¸è¿è¡ŒåŠç©ºæ°”çš„è´¨é‡ï¼Œæœºå°çš„ä¿å…»å¯åˆ†ä¸ºæ—¥å¸¸ä¿å…»å’Œé˜¶æ®µæ€§ä¿å…»ã€‚
日常ä¿å…»é¡¹ç›®Ã˜ 开机å‰é¡»æ£€æŸ¥æœºå°èƒŒé¢å†·å‡å™¨æ˜¯å¦å¹²å‡€ï¼Œä»¥å…æ•£çƒä¸è‰¯ã€‚
Ø 开机å‰æ£€æŸ¥å®‰å…¨è£…置是å¦å¯é 。
Ø 机å°è¿è¡Œ10~20分钟åŽæ£€æŸ¥å·¥ä½œåŽ‹åŠ›å’Œå·¥ä½œç”µæµæ˜¯å¦æ£å¸¸ã€‚
Ø 通入压缩空气åŽè¿è¡Œ10~20分钟检查自动排水器是å¦æœ‰æŽ’水。
Ø 机å°è¯·æ¯å‘¨æ‰“开排污阀二次以上。
Ø 机å°çš„手动排水阀æ¯æ—¥é¡»æŽ’水两次以上。
Ø 环境温度较高时请检查是å¦è¶…过40℃，如超过请改善。
阶段性ä¿å…»é¡¹ç›®Ã˜ æ¯å‘¨éœ€ç”¨å¹²ç‡¥çš„压缩空气或铜刷清ç†æœºå°èƒŒéƒ¨å†·å‡å™¨ä¸€æ¬¡ä»¥ä¸Šã€‚
Ø æ¯æœˆéœ€æ£€æŸ¥è‡ªåŠ¨æŽ’水阀是å¦æœ‰è„å µï¼Œå¦‚è„å µè¯·æ¸…æ´—ã€‚
Ø æ¯ä¸‰ä¸ªæœˆéœ€æ£€æŸ¥æ•£çƒé£Žæ‰‡é£Žå¶æ˜¯å¦æœ‰ä¸è‰¯çš„振动现象。
Ø æ¯å¹´æ£€æŸ¥å¹¶æ‹§ç´§æ‰€æœ‰èžºé’‰ã€èžºæ “å’Œå„ç§å›ºå®šè£…置。
Ø æ¯å¹´æ£€æŸ¥ã€æ¸…ç†å¹¶æ‹§ç´§æ‰€æœ‰çš„电气接头。
附件一:机å°å·¥ä½œåŽŸç†Ã˜ 空气干燥原ç†Â² 潮湿高温的压缩空气æµå…¥å‰ç½®å†·å´å™¨ï¼ˆé«˜æ¸©åž‹ä¸“用）ç»æ•£çƒåŽæµå…¥çƒäº¤æ¢å™¨æˆ–直接æµå…¥çƒäº¤æ¢å™¨ä¸Žä»Žè’¸å‘器排出æ¥çš„冷空气进行çƒäº¤æ¢ï¼Œä½¿è¿›å…¥è’¸å‘器的压缩空气的温度é™ä½Žã€‚
² é™æ¸©åŽçš„压缩空气æµå…¥è’¸å‘器与制冷剂çƒäº¤æ¢ï¼ŒåŽ‹ç¼©ç©ºæ°”ä¸çš„çƒé‡è¢«åˆ¶å†·å‰‚带走，压缩空气迅速冷å´ï¼Œæ½®æ¹¿ç©ºæ°”ä¸çš„æ°´ä»½å› Â² 为达到饱和温度迅速冷å‡æˆæ°´æ»´ï¼Œç»è¿‡æ°”水分离器分离åŽæ°´ä»Žè‡ªåŠ¨æŽ’水阀处排出。ç»å¹²ç‡¥åŽçš„空气压力露点å¯è¾¾2℃。
² 干燥åŽçš„冷空气æµç»ç©ºæ°”çƒäº¤æ¢ä¸Žå…¥å£çš„高温潮湿çƒç©ºæ°”进行çƒäº¤æ¢ï¼Œç»çƒäº¤æ¢çš„å†·ç©ºæ°”å› å¸æ”¶äº†å…¥å£ç©ºæ°”çš„çƒé‡æå‡äº†æ¸©åº¦ï¼ŒåŒæ—¶åŽ‹ç¼©ç©ºæ°”还ç»è¿‡å†·å†»ç³»ç»Ÿçš„二次冷å‡å™¨ä¸Žé«˜æ¸©çš„冷媒å†æ¬¡çƒäº¤æ¢ä½¿å‡ºå£çš„æ¸©åº¦å¾—åˆ°å……åˆ†çš„åŠ çƒï¼Œç¡®ä¿å‡ºå£ç©ºæ°”管路ä¸ç»“露。由于充分利用了出å£ç©ºæ°”的冷æºï¼Œé™ä½Žäº†æœºå°å†·å†»ç³»ç»Ÿçš„è´Ÿè·ï¼Œå¹¶ç¡®ä¿äº†æœºå°å‡ºå£ç©ºæ°”çš„è´¨é‡ã€‚
Ø 冷媒循环原ç†Â² 开机åŽå†·åª’ç»åŽ‹ç¼©æœºåŽ‹ç¼©ç”±åŽŸæ¥çš„低温低压状æ€å˜æˆé«˜æ¸©é«˜åŽ‹çš„蒸气。
² 高温高压的蒸气æµå…¥å†·å‡å™¨åŠäºŒæ¬¡å†·å‡å™¨ï¼Œå…¶çƒé‡é€šè¿‡çƒäº¤æ¢è¢«å†·å´ä»‹è´¨å¸¦èµ°ï¼Œæ¸©åº¦ä¸‹é™ï¼Œé«˜æ¸©é«˜åŽ‹çš„è’¸æ°”å› ä¸ºå†·å‡å˜æˆäº†å¸¸æ¸©é«˜åŽ‹çš„液体。
² 常温高压的液体冷媒æµè¿‡è†¨èƒ€é˜€ï¼Œå› 为膨胀阀的节æµä½œç”¨ 压力é™ä½Žï¼Œä½¿å¾—冷媒å˜æˆå¸¸æ¸©ä½ŽåŽ‹çš„液体。
² 常温低压的液体进入蒸å‘器åŽï¼Œå› 为压力的é™ä½Žæ¶²æ€å†·åª’沸腾蒸å‘å˜æˆä½ŽåŽ‹ä½Žæ¸©çš„气体，冷媒蒸å‘æ—¶å¸æ”¶äº†å¤§é‡åŽ‹ç¼©ç©ºæ°”çš„çƒé‡ï¼Œä½¿å¾—压缩空气的温度下é™è¾¾åˆ°å¹²ç‡¥çš„目的。
² è’¸å‘åŽçš„低温低压冷媒蒸气，从压缩机的å¸æ°”å£æµå›žï¼Œè¢«åŽ‹ç¼©åŽ‹ç¼©åŽè¿›å…¥ä¸‹ä¸€å¾ªçŽ¯ã€‚
Ø 机å°ä¸»è¦ä»ªè¡¨åŠä¸»è¦æŽ§åˆ¶å™¨è¯´æ˜Žæœºå°çš„主è¦ä»ªè¡¨ç”±åŽ‹ç¼©ç©ºæ°”压力表ã€å†·åª’高压表ã€å†·åª’低压表组æˆï¼›ä¸»è¦æŽ§åˆ¶å™¨ç”±ON/OFF按钮开关ã€å†·å†»ç³»ç»Ÿé«˜ä½Žä¿æŠ¤å¼€å…³ã€é˜²å†»å¼€å…³ã€çƒæ°”三通阀组æˆã€‚其功能简介如下：
主è¦ä»ªè¡¨Â² 空气压力表安装在仪表盘上，用于显示机å°åŽ‹ç¼©ç©ºæ°”的压力。表上由若干刻度组æˆã€‚表内下方Mpaå’ŒKg/cm2代表的是压力的å•ä½å€¼ã€‚读å–åŽ‹åŠ›æ•°å€¼æ—¶ï¼Œè§‚å¯Ÿè¡¨ä¸ŠæŒ‡é’ˆæ‰€å¯¹åº”çš„åˆ»åº¦å€¼åŠ ä¸Šå…¶ç›¸å¯¹åº”çš„å•ä½å€¼å³å¯ã€‚
² 冷媒高压表安装在仪表盘上，用于显示冷冻系统的高压端的压力，表上由若干刻度组æˆï¼Œè¡¨å†…下方Psiå’ŒKg/cm2为压力å•ä½ï¼Œâ„ƒä¸ºæ¸©åº¦å•ä½ã€‚读å–åŽ‹åŠ›æ•°å€¼æ—¶ï¼ŒæŸ¥çœ‹æ—¶è§‚å¯ŸæŒ‡é’ˆæ‰€å¯¹åº”çš„åˆ»åº¦å€¼åŠ ä¸Šå…¶ç›¸å¯¹åº”çš„åŽ‹åŠ›å•ä½å€¼å³å¯ã€‚è§‚å¯Ÿæ¸©åº¦æ—¶è¯·æ ¹æ®é“牌上冷媒的ç§ç±»ï¼Œå¹¶å¯¹åº”表上冷媒的ç§ç±»æ¥è¯»å–相对应的温度值。
² 冷媒低压表安装在仪表盘上，用于显示冷冻系统的低压端的压力，表上由若干刻度组æˆï¼Œè¯»æ³•ä¸Žé«˜åŽ‹è¡¨ç›¸åŒã€‚
备注：机å°åž‹å·ä¸åŒå…¶é…备有所ä¸åŒï¼Œå®žé™…é…备以实物为准。
主è¦æŽ§åˆ¶å™¨Â² ON/OFF按钮开关安装在机å°çš„仪表盘上，用于控制机å°çš„è¿è¡Œä¸Žåœæ¢ã€‚
² 冷冻系统高低压ä¿æŠ¤å¼€å…³å®‰è£…在机å°å†…，用于控制冷冻系统高压端åŠä½ŽåŽ‹ç«¯çš„压力，é¿å…机å°çš„åŽ‹åŠ›è¶…è¿‡ä½¿ç”¨èŒƒå›´è€Œé€ æˆè®¾å¤‡çš„æŸå。
² 防冻ä¿æŠ¤å¼€å…³å®‰è£…在机å°å†…，用于控制机å°çš„冷å‡åŽ‹åŠ›ï¼Œé¿å…机å°å†·å‡åŽ‹åŠ›è¿‡ä½Žï¼Œé€ æˆè’¸å‘å™¨å†°å µã€‚
² çƒæ°”æ—路阀安装在机å°çš„冷冻系统管路上，用于控制机å°çš„è’¸å‘压力，确ä¿æœºå°åœ¨ä¸åŒå·¥å†µä¸‹ï¼Œå‡å¯æ£å¸¸è¿è¡Œã€‚
快速通é“冷冻干燥机ã€ä¸åž‹å†·å†»å¹²ç‡¥æœº
related articles
[æŠ€æœ¯æ–‡ç« ]冷冻干燥机的工作原ç†å’Œæ•…障维修
[æŠ€æœ¯æ–‡ç« ]水冷å¼ã€é£Žå†·å¼å†·æ°´æœºä¸Žå¡‘胶厂注æ„事项
[Technical Article] The difference between vacuum drying oven and drying oven
[æŠ€æœ¯æ–‡ç« ]冷冻干燥机在æ“作å‰çš„准备工作
[æŠ€æœ¯æ–‡ç« ]冷冻干燥原ç†
Dental Disposable Saliva Ejector
Dental Saliva Ejector,Disposable Saliva Ejector,Portable Dental Saliva Ejector,Dental Disposable Saliva Ejector
Henan Hanchen Medical Technology Co., LTD , http://www.tchanchen.com