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Cold storage contents
Cold storage projects mainly include: all kinds of cold storage equipment and facilities supplies, materials procurement, library installation body, inside and outside the hoisting machine, laying the connecting pipe, pipe insulation, drainage installation, erection of line connection, control system installation, inside and outside the machine power supply line wiring and system debugging. Power supply required cold storage units that is not included in the present installation cable into the range, cold storage unit and the basic construction and civil engineering complex, we are responsible for the distribution parameters and provide the relevant drawings.
Section II, the main construction methods and technical requirements
First, install the total cold storage
Labor organization, equipment approach, Mixed drawings and technical tests, material procurement support bracket entering production, storage body then stitching, perforated wall, drain line installation, support bracket mounting, welding to install the main line, the main line insulation,
Manifold welding, pipe insulation, laying of control lines, the indoor unit is fixed blow dirt and interface, and an outdoor stationary hanger interface unit piping system, pressure testing, leak testing and drainage, vacuum system, the system charge fluoride, test machine debugging run, finishing the final system acceptance
Second, the installation points and technical requirements:
1.Wall perforation and treatment:
Since the system requirements and drainage lines required storage body and through the wall, should be approved open position and size of the holes, after the correct size marked hole opened in the play hole wall, the wall perforations must sign civil engineering technician comments have no effect on the site after the building structure in order to carry out the drilling operation. Pipeline through the hole in the wall, using the hammer perforation. If the perforated wall Hammer inappropriate in the rear of the consent of the owner's consent is otherwise perforated. The size of the hole may pass through to the line (including insulation) prevail, the line should be located through the wall of the steel casing, pipeline welds can not be placed within the cannula, the cannula should be galvanized metal wall or floor level Sarkozy, but it should be at least higher than the ground20mmVoid Application insulated pipes of the cannula obturator or other non-combustible material, the support may not be a conduit sleeve.
2.Indoor unit is installed:
Step: Determine the location of the indoor unit→Draw lines indexer→Reamer reaming→Library support rod fixed to the top→Screw connection ceiling units→Indoor unit fixed
(1) Step: by drawing pipe→Pipe laying→welding→Blow out→Leak→dry→Insulation
(2) Principle refrigerant pipes should be strictly pipe three principles: drying, cleaning, air tightness.
First, before drying the water into the copper tube mounted prohibited, after the pipe is to be followed by the purge and vacuum dried. Care should be noted that the cleaning tube is clean, purged with nitrogen addition welding is welding, and finally blowing. One is to ensure tightness test weld quality and flare connection quality, the second is the final leak test.
(3) Nitrogen replacement method:
Nitrogen refrigerant pipe must be used when soldering, welding the micro-pressure (3 ~ 5kg / cm²) The nitrogen sparge pipes being welded, the inner tube thus generated will prevent scale.
(4) Refrigerant pipe closure:
Capping important refrigerant pipe, to prevent moisture, dirt, dust and the like into the tube, the refrigerant pipe through the wall must be tightly packed ferrule, a good connection has been temporarily put the nozzle tube installed wrapped.
(5) Purge refrigerant pipe:
A refrigerant pipe blowing the best method for the removal of waste out of the inner tube, the specific method is nitrogen bottle pressure regulating valve of the outdoor unit connected to the pneumatic port, interface with blind plugs in all of the indoor good retention. An indoor interface as the outfall, an insulating material against the nozzle, a pressure regulating valve5kg / cm²Inflate the inner tube, the quick release insulator, dirt and water that is discharged along with nitrogen gas to give way to the hand. Thus several cycles until the discharge of the water free of dirt (do all indoor units each).
Further, for the liquid pipe and the pipe to be performed separately.
(6) Brazing the refrigerant pipe:
a.Refrigerant preparation before brazing tube: standard brazing rod quality, ready welding equipment, to brass cut surface smooth, without burrs, etc. back to convex defects, the cutout allows the inclined plane, deviation of diameter of the tube1%.
b.Refrigerant pipe should be brazed or phosphor bronze electrode silver electrode, soldering temperature700-845℃, Brazing work easily in a downward or horizontally laterally, to avoid possible overhead welding, the joint branch port must be kept horizontal.
c.Horizontal tubes (brass) spaced supports the following criteria:
NominalΦ20the followingΦ25-40 Φ50
Interval (m)1.0 1.5 2.0
Note: Copper metal can not be supported by the clamping bracket should be in a natural state, hold the copper tube through the insulation layer, to prevent the generation of cold bridges.
d.Welding personnel should have the necessary qualifications, to posts.
e.The gas pipe during the welding operation of the valve, the cooling process must be carried out (with a wet cloth wrapped body), or cause leakage
(7) Diameter of less thanΦ19.05mmBrass all using field simmer, bending or cold bending special bending tools, should not be greater ellipticity8%, Mounted side by side pipe bending radius should be the same distance, slope, slope should be consistent. more than theΦ19.05mmBrass stamping elbow should be used.
(8) Flared connection:
The refrigerant and the indoor unit are connected using brass flare connection, so pay attention to the quality of the expansion of the bell mouth. Wherein the depth of the flared bell mouth is not less than the diameter, the flaring should welcome refrigerant flow direction, pipe cutting using a dicing blade, coated with a little refrigeration oil on the inner surface of the flared when flared and locknut, size and flaring nut torque in the following table:
Nominal diameter copper tube flared tube diameter sizes torque (kgf-cm)
1/4 Φ6.35 9.1-9.5140-180
3/8 Φ9.52 12.2-12.8340-420
1/2 Φ12.7 15.6-16.2340-420
5/8 Φ15.88 18.8-19.4680-820
3/4 Φ19.05 23.1-23.71000-1200
4, All must use the refrigerant pipe insulation pipe dressing bandage, the sleeve is too slab to steel.
5, Drain installation: the use of drainsPVCorPPRPlastic tube:
(1) The steps of: connecting pipe→Laying heating wires→Check the water leak→Heat insulation
(2) Before pipeline installation must be dirt and rust in the pipes cleaned, the pipe openings should be sealed protective measures taken during installation to a halt.
(3) Drains effective distance as short as possible in the interior, the horizontal drain pipe should slope gradient is1/100to1/50。
(4) Between the drain and the drain compartment tray dryer for a period of preferably flexible connections, tray and compartment dryer condensate drain should be higher than the drain interfaces,PVCDedicated linePVCGlue connection. Water drainage system leak test can be water-filled test, no leakage is acceptable.
(5) After the pipe installation system should be flushed before connecting the cleaning system.
6The control line operations:
Control lines using shielded wire laid along the tying refrigerant pipe, the indoor control part through tubes disposed dark, disables the power and control lines bundled together again, to prevent interference.
7, Insulation work:
Work selection basis having adiabatic design requirements, put together the bushing insulation construction, weld and leaving the last weld process. The absolute prohibition of insulation off phenomenon during the construction period, be sure to use insulation sleeve lap belt strapped up.
8, Units installed outside the library:
(1) Unpacking outside-unit equipment, inspection equipment fill opening inspection record sheet;
(2) Handling and lifting equipment unit outside the library;
(3) Seated on the outer gallery roof base unit (civil complex), with the base unit or using the foot bracket. Between the library and the library machine outside the machine, technical regulations shall correlation between the outdoor unit of the building to do it.
9, Airtightness test:
(1) Sequential operations: refrigerant piping completed→Nitrogen pressure→time control→Check pressure→qualified
(2) Organization and division of testing personnel.
(3) Essentials: a refrigerant tube to be pressurized with dry nitrogen, was slowly pressurized test:
The first stage:3.0 kg / cm²Pressurization3Minutes or more;
second stage:15 kg / cm²Pressurization3Minutes or more;
The third stage:30 kg / cm²Pressurization24hour
Whether the observed pressure drop, if no decline is qualified, but the pressure will change the temperature change, every change1℃, There will be pressure0.1 kg / cm²Changes, it should be amended. Check for leaks can be affected by a sense of the sense of hearing, soapy water leak detection, pressure test after the completion of nitrogen to nitrogen discharge3 kg / cm²After addingR22To pressure5 kg / cm²Leak detection with electronic leak detector.
(4) During the test must be completed tightness test record (record fill text clear, real)
10And dried in vacuo:
(1) Nitrogen pressure test the system after passing to vacuum drying, vacuum drying should meet quality requirements.
(2) And dried in vacuo to choose a rotary pump (displacement4l / min) Before use check evacuated vacuum capacity is required to achieve-755mmHgBefore proceeding.
(3) In the following order:
⑴Continued operation of the vacuum pump vacuum table2Hour or more (the degree of vacuum should be-755mmHgAbove), such as reach-755mmHgShould continue pumping1Hours if not reach should check for leaks.
⑵achieve-755mmHgAfter, you can place the1Hours, vacuum gauge does not rise to qualified, such as rise indicates a leak port or water, the system should continue processing.
⑶After vacuum passing the test, calculated according to the amount of refrigerant filling, and opening the valve (note should be evacuated from both sides of the pipe and a liquid pipe).
⑷In special cases, special vacuum drying compartment plus nitrogen.
(4) The above test case record into the relevant form.
11, Freon refrigerant filling:
Filling Freon refrigerant filling is performed in accordance with the requirements of technical information.
Third, the main difficulty of construction and cold storage solutions
To ensure that the refrigerant pipe is absolutely clean, free of impurities, moisture-free.
The solution is:①Selection must be strict.②Φ19.05The copper tube using the whole bundle later, minimize weld.③It guarantees the protection of nitrogen welding.④To meet the requirements of blowing dirt.⑤To achieve the vacuum requirements.⑥Freon refrigerant added to the system used by the US DuPont, France Alto or domestic brands.
Fourth, cold storage project engineering and protection methods
The main body content protection is a library, the library inside and outside the unit.
Compartment storage body and installed in the machine, followed by removal of the decoration film. Outside the library and then dismantling the unit when in place.
All lines are not connected library, all use sign Zhakou protect the front outside the machine.