Original title: Use and installation of drying filter In the refrigerant system,
many harmful substances will enter the pipeline through various ways, and the
common ones are as follows: 1. Production or maintenance process: At this time,
the refrigerant system will be open to the outside, regardless of the length of
time, there will be moisture, dust into the system pipeline, in the welding
process, if there is no nitrogen protection, there may be copper oxygen film, or
even welding slag; 2. Filling refrigerant or refrigerant oil: If there are many
solid impurities and moisture in these things, they will be brought into the
system and corrode the metal parts in the system; 3. In the operation of the
refrigeration system: In the operation, when the refrigerant contains water, it
will hydrolyze to produce acidic substances, which will corrode the metal. The
mixture of refrigerant and lubricating oil can dissolve copper and bring it to
the compressor to form a copper film on its metal surface, thus affecting the
operation of the compressor. 4. Refrigerant oil: When the temperature is low to
a certain temperature, the refrigerant oil will precipitate stone toad, and the
POE oil used for environmental protection refrigerant has strong hygroscopicity,
so it is easier to hydrolyze acidic characteristics. The existence of the above
substances will seriously threaten or destroy the performance of the moving
parts in the system and the cylinders and refrigeration systems that need
compressed gas, so they should be removed in time. Expand the full text The
materials that play a role in the dry filter mainly include: 1. Metal filter
screen: filter large solid particles (mainly used in small and medium-sized
systems that are not sensitive to moisture, such as R22 and mineral oil). 2.
Polyester filter screen: filter tiny particles. 3. Glass wool: filter tiny
particles. 4. Molecular sieve: It filters large particles of solid impurities,
mainly absorbs water, which is 3-4 times that of other substances, and can also
absorb acidic substances nearby. 5. Activated alumina: absorbs water, mainly
acidic substances. 6. Activated carbon: It absorbs paraffin, but because the
refrigerant oil will precipitate paraffin only when the temperature is below -35
degrees,
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filter dryer ,
wiped film
distillation, it is not needed in the system operating at medium and high
temperatures. The use of dry filter is divided into: Filtration capacity:
Filters the system of harmful substances, thus protecting important components
such as expansion valves and compressors. Moisture absorption capacity: For
refrigeration products produced according to the standard process, it is
difficult to determine how much moisture absorption capacity of the dryer needs
to be used, so the general dry filter production is nominal according to the
requirements of the standard. Ability to adsorb acid and ester substances:
Experiments show that the ability of the dry filter to remove acid and ester
substances is directly proportional to the mass of the adsorbed substances,
while the size and outer surface shape have little effect on this ability. In
addition, there is no better industry-recognized method to measure this ability.
Paraffin adsorption capacity: For the refrigeration system under low temperature
conditions, because the lubricating oil will precipitate paraffin, which will
cause damage to the valve, it should be removed in time, and activated carbon is
commonly used for adsorption. Refrigerant flow: Since excessive pressure drop
will affect the system capacity, the smaller the pressure drop through the dry
filter, the better. Classification of dry filter: Filter-driers for the liquid
line and filter-driers for the suction line all remove substances that can
damage the system, but with different emphasis. Dry filter for liquid pipe: It
is mainly used to protect the stop valve, expansion valve and other valves, and
to avoid the blockage of capillary and other throttling elements. It is a
standard configuration in the refrigeration system. The liquid tube drying
filter is usually followed by a liquid microscope. Suction pipe dry filter:
mainly protect the compressor. Dry filter for suction pipe is generally used in
two situations in the industry. 1. On-site installation system: As the on-site
installation is different from the factory, the on-site environment is complex
and the cleanliness is poor, so it is better to install a dry filter in the
suction pipe. 2. Large system: Because the cost of the compressor is relatively
high, it is worthwhile to install a removable dry filter in the suction pipe to
protect the compressor. In order to ensure that the pressure drop is as small as
possible, the drying filter of the suction pipe is mainly used when the
compressor is burned, so it can adsorb a large amount of water and acidic
substances or solid impurities in a short time, which will reduce the flow
capacity of the drying filter, thus affecting its performance. The dry filter
needs to be replaced. ： The drying filter is generally located behind the liquid
reservoir in the liquid pipe, and in front of the sight glass, stop valve and
thermal expansion valve; there are two positions in the suction pipe: 1. Between
gas-liquid separator and compressor; 2. Between the four-way valve and the
gas-liquid separator. However, it should be between the four-way valve and the
gas-liquid separator: 1. If impurities enter the suction pipe, it may block the
filter screen of the oil return hole of the gas-liquid separator, which can be
avoided if there is a filter in front of it; 2. The gas-liquid separator is
required to be installed as close as possible to the compressor. For the drying
filter in the liquid pipe of the heat pump system, because of the bidirectional
flow, there are some special installation. In practical application, there are
the following common designs: 1. Only installed on the refrigeration cycle; 2.
Use four one-way valves to set the reservoir,
wiped
film distillation, drying filter and expansion valve on the common pipeline,
then refrigeration and heating can be used; 3. Two one-way valves and two drying
filters are used to work in the refrigeration and heating cycle respectively; 4.
Use two-way drying filter. In addition to the drying and filtering work of the
normal refrigeration system, the drying filter also has an important function of
cleaning the system after the compressor is burned down. Return to Sohu to see
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