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Dryer dew point instrument manufacturers price

Product Keywords: Dew point meter Dew point meter Dryer dew point price Online dew point meter
  • Product name : Drying machine dew point meter factory price
  • Product Numbers: EA2-OL
  • Product Trademark: Michell
  • Product specifications: imported
  • Reference price: 1200
  • Updated: 2019/12/27 8:37:08
  • Click times: 24179 times

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Dryer Dewpoint Meter-Basic Principles

Application of dew point meter in freeze dryer, adsorption dryer, low dew point dehumidifier, deliquescent dryer, plastic / plastic dryer

Gas law: PT = PA + PB + PC + ……. + PW (PW stands for partial pressure of water vapor) kPT = k (PA + PB + PC + ……. + PW) PW / PT = C

Meaning of dew point: The temperature at which dew or other states of condensate form when the gas is cooled by constant pressure. Generally includes "frost spots".

Ppmv's explanation: The ratio of the partial volume of water vapor in wet gas to the partial volume of dry gas multiplied by 106 is sometimes expressed as the ratio of the partial volume of water vapor to moisture (that is, the total volume of gas).

Dryer Dew Point Meter-Application Type

1. Working principle of freeze dryer:

Freeze-drying is a technology that uses the principle of sublimation to dry. It is a process that quickly freezes the dried substance at low temperature, and then in a proper vacuum environment, the frozen water molecules are directly sublimated into a process of water vapor escape. Freezing The product obtained by drying is called lyophilizate, and the process is called lyophilization. The freeze dryer is composed of a refrigeration system, a vacuum system, a heating system, and an electrical instrumentation control system. The main components are drying box, condenser, refrigeration unit, vacuum pump, heating / cooling device, etc. Its working principle is to freeze the dried articles below the triple point temperature, and then sublimate the solid water (ice) in the articles directly into water vapor under vacuum conditions, remove them from the articles, and dry the articles. After pre-processing, the materials are sent to the freezing bin for freezing, and then sent to the drying bin for sublimation and dehydration, and then packed in the post-processing workshop. The vacuum system establishes low-pressure conditions for the sublimation drying warehouse, the heating system provides the sublimation latent heat to the material, and the refrigeration system provides the required cooling capacity to the cold trap and the drying chamber. The dew point of a refrigerated dryer is generally around -20 C. The recommended range of the dew point meter is -60 C to 20 C. The accuracy is: 2 C, so that it can truly and quickly reflect its dewpoint value and also reflect Whether the working condition of the drying system is normal, effectively ensuring the dew point value of the drying gas.

2. Working principle of adsorption dryer:

Adsorption drying is the use of adsorbents for the selective adsorption of water vapor in compressed air for dehydration and drying. A new generation of adsorption dryers combines the advantages of pressure swing adsorption and temperature swing adsorption and adsorbs at room temperature and high steam partial pressure ( Work); analysis (generation) at higher temperature and low steam partial pressure, that is, the moisture absorbed by the adsorbent during the adsorption process, relying on the high-quality reproduction (dry air heating) of thermal diffusion and low partial pressure in the regeneration process The combined effect of this mechanism has been completely eliminated. Adsorption: Wet air enters the A drying tank from the lower pipe system through the A valve, flows through the adsorbent bed from the bottom up, and the dried air is discharged from the upper pipe system. Regeneration and blowing cold: A small amount of dry air passes through the upper pipe system regeneration gas regulating valve to decompress and enter the heater for heating. This part of the hot air (called regeneration gas) enters the B drying tank. Analyze and regenerate the adsorbent in the B tank, restore the drying capacity of the adsorbent, and regenerate the exhaust gas to the atmosphere through the lower valve B valve and muffler. Equalizing pressure: After the regeneration of the adsorbent is completed, the B valve is closed, and the B drying tank is gradually increased to the online working pressure, ready to be switched. Switching: The B valve of the lower pipe system is opened, the A valve is closed, the A valve is opened, the A and B drying tanks are switched, the B tank enters the adsorption, and the A tank is depressurized and regenerated. The working sequence, working time and heating temperature are automatically controlled by the controller to achieve the drying effect. According to the drying principle of adsorption, the dew point value is generally around -40 C. The recommended range of dew point instrument is -80 C to + 20 C, and the accuracy is 2 C. This can ensure the reliability of the measured value. It also makes the anti-fouling and oil-resistant characteristics of the dew point meter more stable.

3. Working principle of low dew point dehumidifier:

a. Cooling and dehumidifying method: The air in a certain state is cooled below its corresponding dew point temperature, and the gaseous water in the air is condensed into liquid water and precipitated from the air, thereby achieving the purpose of dehumidification. The cooling medium may be chilled water, low-temperature brine, refrigerant, and the like. Because the moisture in the wet air is easy to freeze on the surface below 0 C, there is a certain temperature difference between the processing air and the surface of the heat exchanger, which results in that the dew point temperature * that the processing air can reach is as low as 0 C. To meet the general dehumidification requirements required by industry, low-temperature brine and increased air handling air volume are bound to increase the energy consumption of refrigerators, fans, and pumps, and the equipment needs to be larger.

b . Compression and dehumidification method: Compress the air to a certain pressure to make the water in the air saturated and then cool down to remove the water. This method can achieve a lower dew point, but it is only suitable for instruments and meters that require a small amount of dry air, and the operating cost is large.

c . Chemical dehumidification method: solution absorption dehumidification: the use of a high-concentration solution that absorbs water and air contact each other to remove water. This method can continuously dehumidify, but the solution is corrosive and easy to take away with the air. The solution is easy to crystallize during regeneration, the concentration is difficult to control, and maintenance is troublesome.

d . Wheel adsorption dehumidification: Use moisture absorption material (silica gel or molecular sieve) in the honeycomb rotor to absorb air moisture. This method can continuously dehumidify and obtain stable dry air. Especially when the humidity is low, it has the incomparable advantages of other dehumidification methods, and the humidity is easy to control. It can be made into different specifications according to actual needs. The dehumidification effect is relatively good, and the dew point value can be about -80 C. This low-humidity dehumidifier, Oberth recommends the range of the dew point instrument is -100 C to 20 C, and the accuracy is 2 C. Data, dew point -80 ℃ (pressure is a standard atmospheric pressure, temperature 20 ℃), the relative humidity is: 0.002%, the corresponding moisture content is 0.55 PPM, we can see the dew point of the dehumidified dry gas and the relative humidity \ PPM This requires our sensors to have a wide range, high accuracy, high stability and other characteristics, otherwise it is impossible to accurately measure its true dew point value.The dew point transmitter of the British company MICHELL, which is the agent of Albert, has obtained China For the administrative measurement approval certificate, most of the measurement standards used by metrology institutes are also products of MICHELL, with reliable accuracy and good stability! It is an ideal product for low dew point dehumidifiers.


4. Working principle of deliquescent dryer:

The air passes through the filter and is heated by the heater (the heater can use electric heating, oil-fired hot air stove, natural gas hot air stove, etc., and different inlet air temperatures must be designed according to different materials). The hot air generated is from the volute channel on the top of the drying room. The uniformly rotating airflow generated by the hot air distributor enters the drying room. The material liquid is pumped from the material liquid tank through the filter to the centrifugal atomizer at the top of the dryer, or a high-pressure nozzle, which generates a dispersed, fine material mist. The material mist contacts the swirling hot air, and the water quickly evaporates. In a short time, the finished product is dried. The finished product is discharged from the bottom of the drying tower and the cyclone, and the exhaust gas is drawn out by the fan.

5. Working principle of plastic / plastic dryer:

In the drying process, a large amount of heat energy is consumed. In order to save energy, some materials with high moisture content, suspensions or solutions containing solid materials are generally mechanically dehydrated or heated and evaporated, and then dried in a dryer to obtain dry solids. During the drying process, it is necessary to complete the transfer of heat and mass (moisture) at the same time to ensure that the wet partial steam partial pressure (concentration) on the surface of the material is higher than the wet partial steam partial pressure in the external space, and that the heat source temperature is higher than the material temperature. The heat is transferred to the wet material from the high-temperature heat source in various ways, so that the moisture content on the surface of the material vaporizes and escapes to the external space, so that the difference in moisture content appears on the surface of the material and inside. The internal moisture content diffuses to the surface and vaporizes, so that the moisture content of the material is continuously reduced, and the overall drying of the material is gradually completed. The drying rate of the material depends on the surface vaporization rate and the internal moisture diffusion rate. Generally, the drying rate in the early stage of drying is controlled by the surface vaporization rate; then, as long as the external conditions of drying remain unchanged, the drying rate and surface temperature of the material remain stable. This stage is called the constant-speed drying stage; when the moisture content of the material decreases to a certain level To the extent that the internal moisture diffusion rate decreases to the surface and is less than the surface vaporization rate, the drying rate is mainly determined by the internal diffusion rate and continuously decreases with the decrease of the moisture content. This stage is called the reduced-speed drying stage.

Why should plastic products be dried? Because in most plastic manufacturers, most of the reasons for poor molding of plastic products come from insufficient dehumidification and drying. The American Plastics Association has suggested that the plastic before molding must be dried to a moisture content of less than 0.02%, otherwise it is difficult to ensure the stable quality of the product. For example, shortcomings such as poor transparency, sticky runners, burrs, bubbles, cuts, cracks, poor dimensional stability, internal stress, and insufficient physical strength of the product are prone to occur. Especially highly impregnated water-based plastics such as: PET, PBT, PA, PC, PS, ABS, POM, PP, PE, PVC, EVA, etc., need ultra-low dew point Dew point-40 ℃ drying equipment. In order to solve the above problems, Oberthur company has introduced a range of dew point meters that can select multiple ranges. The optional measurement ranges are: -100 C to 20 C, -80 C to 20 C, -60 C to 20 C,- 50 C to 20 C, which is intended to be tailor-made for customers * as a suitable dew point measuring instrument. It provides high cost performance while ensuring reliable measurement accuracy and stable performance.

Dryer Dew Point Meter——Comparison of Dehumidifying Capacity of Various Dryers


It can be seen from the above comparison that the dehumidification capacity of different dehumidification methods is different, that is, the level of the dew point depends entirely on the dehumidification method. Whether using a dryer or a dehumidifier, it is important to be able to measure the humidity value in plastic raw materials. British Michel (MICHELL) instrument is the world's largest manufacturer of humidity dew point instrument, has more than half of the market share in the European humidity detection field, has more than 35 years of professional technology. Almost all standard laboratories in developed countries such as EU / USA use MICHELL products as standard instruments. For the dehumidification and drying industry, Obert company uses MICHELL's dew point sensor for secondary development, and effectively monitors the dew point of the dehumidifier and dryer online, which reduces a lot of trouble for users in controlling product quality. The EA2-TX-100-HZ series dew point meter professionally prepared on a dehumidifier and dryer has the characteristics of wide range, high accuracy, good stability, easy to use, etc., and is an ideal product for measuring the dew point of a dehumidifier.

Dryer dew point meter-technical parameters

Michell has developed an Easidew series of online dew point meters for a wide range of dew point ranges based on the dehumidification capabilities of various types of dryers and the application in different industrial environments. The typical representative of Easidew series is EA2-TX-100! It can be applied to different industrial occasions and working conditions, and has the characteristics of easy installation, high accuracy, strong stability, long practical life, pressure resistance and shock resistance!
EA2-TX-100 technical parameters:

Transmitter form Michell Advanced Ceramic Humidity Transmitter

Calibration range -100 ~ + 20 C

Power 12 ~ 28 VDC

Output 4 ~ 20 mA current source covering the entire dew point range

Transmitters are fully interchangeable

Accuracy 2 C

Working temperature -40 ~ + 60 C

Temperature coefficient with temperature compensation

Working pressure 30 MPa

Flow When mounted on standard sampling module: 1 ~ 5 NL / min

When the installation method is direct insertion (80 μm sintered protective sleeve): 0 ~ 10 NL / min

Traceability index -75 ~ + 20 C dew point traceable to NPL (UK) and NIST (USA) For dew point <-75 C, the basic cold mirror dew point hygrometer is the direct reference standard]

Environmental protection IP65 (NEMA 12) with standard connector

IP66 (NEMA 4) with molded connector option

Weight 0.15 kg

Error condition indication Condition output

Transmitter error 23 mA

4 mA below dew point range

20 mA beyond dew point range

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