Introduction
There has been a tracking audit of ground source heat pump system installation project, in the tracking audit process found that the equipment piping installation in the equipment room is extremely important, but the construction personnel are not clear enough about the construction process and construction requirements, etc., so this article according to the content of the installation, the design requirements of the ground source heat pump system installation in the equipment piping installation of equipment in the equipment room, construction technology and its technical requirements, for peers to learn from. And its technical requirements, for peer reference.
1 pipe installation content
Pipe installation in the machine room, including the machine room in the ground source side of the system supply and return piping, air conditioning side of the system supply and return piping, softened water replenishment piping installation. All pipes are installed openly with support hangers. Support hangers are fixed on the structural walls, roof beams and other structural components.
2 piping design requirements
Ground source side of the room, air conditioning side of the supply and return water pipelines are all used in line with the national acceptance standards of seamless steel pipe, the form of connection for the welded connection; sanitary hot water system pipelines are all galvanized plastic-lined steel pipe, the connection for the groove pieces connected. The valves and filters of the air-conditioning system in the server room are all manufactured by regular large factories. Air-conditioning system in the room valves, fittings and piping need to be in line with national standards of manufacturing licenses, certificates of conformity, and related material quality certificates, the model specifications to meet the corresponding requirements for the design, in the implementation of the installation must be in accordance with the design drawings for the installation; to follow the design and process requirements for the pipeline to select the type of support bracket, in particular, pipeline support bracket categories, materials, size, accuracy and welding should be In particular, the type, material, size, accuracy and welding of the pipeline hanger should be in accordance with the requirements of S161 "pipeline hanger". At the same time, cold water piping and support hangers should be added between the thickness of the same insulation layer of corrosion-resistant wood bracket, the main purpose is to avoid hot and cold bridge.
In the installation of the pipeline should be installed in the same plane of the pipeline and valve installation, follow the principle of vertical and horizontal, to maintain the deviation of 3mm, in which the pipeline installation of the horizontal and vertical standard should follow the design standards; which should be installed slope of 3 ‰. In order to facilitate maintenance and inspection, and thermal insulation considerations, flanges, welds and other connections shall not be installed immediately adjacent to the wall or floor, in which the pipeline butt joints and flange interfaces shall not overlap with the support bracket. It should be noted that the check valve, pressure reducing valve can only be set in the horizontal pipeline, and the installation of horizontal pipeline valve handwheel should be installed in the direction of the upward direction, in the installation of pipeline piping to transport liquids or fluids should be piped from the side of the pipeline or right below the connection.
3 Pipe installation process and hard standards
3.1 Pipe installation process
3.2 Pipe cutting and discharging
To cope with the different pipe sizes and materials, the cutting methods available are as follows: choose manual, mechanical, flame cutting, it should be noted that the welding can not be used in lieu of cutting, cutting, pay attention to the pipe mouth leveling, removal of pipe Burrs on the inner wall, butt-welding weld, beveling machine or manual beveling, generally use V-bevel for butt-welding, selection angle of 60 ℃, for flame cutting shall remove burrs on the inner wall of the tube. In response to the flame cutting of the tube surface oxides, you can use an angle grinder to grind until it is smooth, the tube size should be installed according to the actual measurement of the size of the measurement, the two closed between the tube should be measured again to determine the size of the material.
3.3 Pipe butt welding
3.3.1 Pipe welds should be located in accordance with the following provisions:
(1) straight pipe section of the two annulus spacing is greater than or equal to 10cm, and to be larger than the pipe outer diameter.
(2) weld when the starting point of the bend is greater than or equal to 10cm for, and to be larger than the pipe outer diameter.
(3) ring weld from the support bracket net distance should be greater than 5cm.
(4) pipe longitudinal and transverse weld shall not leave holes, welding bracket and other instrumentation pipe.
(5) Welding requirements:
a. Butt welding personnel required to hold a welder's license.
b. Welding materials should be avoided to put in the wet place, keep dry and have the relevant certificates of conformity and material certificates and so on.
c. Welding work can not be carried out in poor conditions, such as rain, temperature below 0 ℃ or typhoon place, if the site does not meet the conditions should be taken when the corresponding protective measures can be welding work.
3.3.2 Welding work
(1) Welding materials: welding rods using knot 422.
(2) dry welding rods, such as moisture can be dried.
(3) Generally grind the weld bevel into V-bevel.
(4) Clean the bevel inside and outside of the oil, rust and so on.
(5) After welding each level, in order to prevent surface defects affecting the welding work, you need to be on the electric wire brush to clean the weld channel.
3.3.3 Quality requirements: the weld should be reduced at the size of oversize, weld tumor, biting edge, arc crater, surface porosity, and flux seepage and other defects appear. After welding, the surface of the weldment should be fully inspected and the quality of the weld meets the requirements of Ⅳ weldment.
3.3.4 After welding, the welder should remove the residue and spatter, check the surface, qualified mark.
3.3.5 Welding cracks welders are prohibited from unauthorized treatment, investigate the cause and develop a rework process before processing.
3.4 Valve Installation
The valve before the installation of regular sampling checks. Check the use of field strength tightness test check, the main pipeline valves and cut off the role of the valve comprehensive inspection, other parts of the valve according to the various specifications of 20% sample sampling. Strength test test pressure value should be 1.5 times the nominal pressure, the test time shall not be less than 5 minutes, the qualifying standard for the valve shell filler does not leak; tightness test test pressure value should be 1.1 times the nominal pressure, within 60 seconds of the test pressure value is unchanged and the valve valve sealing surface without leakage, to meet the above conditions are qualified. Installation after passing the test; initial installation, should check the model, check the quality of the valve and determine the direction of installation, close the screw and flange connection valve before its installation, in the correct instructions to operate the valve drive and operating machinery. Prohibit the use of mallet or sharp instruments to knock its sealing surface or valve parts.
3.5 Flange and gasket installation
Flange nominal pressure and equipment and valves are consistent, flange flatness deviation is less than the flange outer diameter of 1.5 ‰, and not greater than 2mm, prohibit strong screwing bolts to eliminate defects, flange fastening bolts focus on symmetry, so that the force is uniform, tightening of the bolts exposed length shall not be greater than 2 times the pitch, fastening of semi-precision hexagonal bolts with Use semi-precision hexagonal bolts to fasten the flange bolts of low pressure pipelines. Spring gasket should be used on the connecting flange of the vibrating equipment to keep the flange sealing perimeter neat, and the flange sealing surface corresponds to the gasket size.
3.6 Pipeline pressure test flushing
Pipeline installation is completed, the piping system must be designed and standardized requirements for sub-system flushing, and pressure test. Flushing to the maximum flow rate of the system, the system supply and return piping in the machine room short-circuit connected, and then open the system circulating pump for flushing, and through the manifold drain valve, pump inlet filters and other parts of the circulating water in a timely manner to remove debris, when the discharge of the water color is clear, and through the body and there is no gravel, rust, and other debris when the party is qualified. Pressure test test value of air-conditioning system 0.9MPa, sanitary hot water system 0.6MPa, stabilized pressure for 10 minutes, the pressure drop is not greater than 0.02MPa, and then reduced to 0.6MPa and 0.4MPa, respectively, check the system piping without leakage is qualified.
4 Conclusion
In summary, I take the identity of an auditor to explain the ground source heat pump system in the equipment room piping installation construction process and technical requirements, but also in order to audit the project with the construction unit to better communicate, so as to avoid unpleasant.
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