The machine is mainly composed of the following systems: oil inlet filter system; vacuum pumping system; vacuum breaking system; vacuum spray system; oil outlet filter system and recoil system.
Oil inlet filter system: consists of coarse filter, fine filter and special filter.
Its function is to filter the oil in advance. The coarse filter is 40~100μ, the fine filter is 20~40μ, and the special filter is 20~40μ. The special filter is set according to the special requirements of the user, such as adding a chemical agent inlet to remove the acidity or alkalinity of the oil; using a line gap or glass brazing filter cloth structure to eliminate oil foam. The selector valve should be closed when in use.
Vacuum pumping system: composed of vacuum pump, water separator, one-way valve and cooler.
Its function is to evacuate the vacuum tank into a vacuum negative pressure (generally 380~610 mmHg or lower), so that the water in the oil can volatilize at a lower temperature; the extracted water vapor passes through the cooler and water separator Condensation, precipitation; one-way valve prevents the vacuum pump from reversing. General pneumatic components cannot be used for the water separator and one-way valve, and pneumatic components suitable for working under negative pressure must be used.
The cooler is generally a tower structure with a large volume, and is equipped with multi-faceted hollow polypropylene plastic balls with good hydrophilic performance, high temperature resistance, corrosion resistance, and large specific surface area of total humidity. The hot and humid gas drawn from the vacuum tank enters the tower tangentially and obliquely along the tower wall, the flow velocity slows down sharply and forms a downward vortex airflow, and the flow velocity further slows down after encountering polypropylene plastic balls, and quickly condenses into water droplets.
Vacuum breaking system: composed of intake valve, dry filter and vacuum breaking valve.
Its function is to supplement air and reduce vacuum. Under vacuum negative pressure, the water vapor content is easily saturated and difficult to extract. Air should be added periodically to destroy the saturation of water vapor, so that water vapor can continuously evaporate in the vacuum tank for easy extraction. The on-off of the vacuum breaking valve is controlled by the signal of the liquid level controller. Dry filters are used in areas with high filtration accuracy and high air humidity. Dry filter agents such as calcium chloride, caustic soda, caustic potash, silica gel, aluminum glue, etc. are added to the filter to remove the humidity of the supplemented air.
Vacuum sprinkler system: consists of heater, vacuum tank, sprinkler, temperature controller and liquid level gauge.
Its function is to heat the oil to a certain temperature, and then spray the oil to make the free water, emulsified water and dissolved water in the oil volatilize in the vacuum tank. The heater has a serpentine armored heating tube directly heated in the tank, which has a high thermal efficiency; multiple straight tubes are heated in series, and this method is commonly used because it is easy to maintain the heating tube. The box-type far-infrared heating method, in this way, the oil is heated evenly, and the oil will not produce carbides and entropy changes that reduce the performance of the oil due to contact with the high-temperature heating tube. The sprinkler is a shower canopy or spray pipe evenly covered with φ1~φ2 small holes, because the small holes are easy to be blocked, so the sprinkler should be easy to disassemble.
After the oil temperature is measured at the temperature control point, the heater is turned on and off through the temperature controller, so that the oil temperature is controlled at 45 oC ~ 75 oC. The liquid level controller has a float type, a float sensor type outside the tank and an infrared control type. There are 4 control points for the liquid level. The upper limit position stops the vacuum pump to prevent oil from entering the vacuum pump; the lower limit position stops the oil pump to avoid air suction of the oil pump; Upper middle and lower middle positions. The vacuum tank is the heart of the oil filter. It has a large volume, and the tank is filled with a certain degree of hydrophilic and corrosion-resistant filler, such as polypropylene plastic balls, to accelerate water volatilization. Foreign Pall Company sets a high-speed turntable in the vacuum chamber, using centrifugal force to make the oil have a huge surface area per unit volume to increase the water removal rate without heating.
Oil outlet filtration system: It consists of oil well pump, safety valve, metal filter (10~20μ), fine filter (5~10μ), ultrafine filter (1~5μ).
The main function is to extract the oil from the vacuum tank, and return it to the working box (tank) after several times of fine filtration. Oil well pumps should generally use hydraulic devices with high self-priming vacuum, such as gear pumps, screw pumps, etc. The nominal displacement of the oil well pump is the main parameter of the oil filter unit—the nominal flow rate, which is also the main parameter for the design and calculation of the oil filter unit . The metal filter element is a magnetic filter element to remove metal particles in the oil; fine filtration and ultra-fine filtration are generally sintered or glass-brazed coalescing, non-woven material filter elements, and the filtration capacity of the filter element must be pumping. 3~5 times of the nominal displacement of the oil pump. When the filter element is blocked, the safety valve opens automatically to protect the oil well pump and filter device.
Recoil system: When the oil pressure gauge reaches and exceeds a certain reading (0.25MPa), the indicator light will light up and alarm, indicating that the oil outlet filter element has been seriously blocked. At this time, the recoil system should be used to clean the filter element. Backflushing can remove the accumulated pollutants on the filter element, so that the filter element can be reused and prolong the life of the filter element.
Use a hose to connect ports C and A, close recoil lock valve b, open oil outlet valve A, valve B, and valve C, and turn on the oil well pump. The spools of each filter are recoiled, and then discharged through port B.
Close recoil lock valve a, b and selector valve, open oil inlet valve D and vacuum breaker valve, turn on oil well pump, pressurized oil opens the safety valve, recoils each oil inlet filter, and then discharges through D port to realize each inlet Backflushing of the oil filter spool. The oil outlet of each filter should be arranged in the tangential direction of the tank wall, which is conducive to the formation of vortex turbulence during recoil to improve the recoil effect without damaging the valve core.
