Installation valve 14 major taboo fluorine lining valve model preparation method

Installation valve 14 major taboo fluorine lining valve model preparation method

Installing valves is not an easy task. There are 14 taboos, do you know? What would happen if these taboos were violated? How do you solve it? No. 1 Hydrostatic test at negative temperature during winter construction.
Installing valves is not an easy task. There are 14 taboos, do you know? What would happen if these taboos were violated? How do you solve it?
No-no 1
In winter construction, hydrostatic test is carried out under negative temperature.
Consequence: The pipe freezes quickly during hydrostatic test, causing the pipe to be damaged.
Measures: Try to carry out hydrostatic test before winter application, and blow the water clean after pressure test, especially the water in the valve must be *** in the net, otherwise the valve will freeze crack.
The project must be carried out in winter hydrostatic test, to keep the indoor temperature is positive, after the pressure test to blow the water. When the hydrostatic test cannot be carried out, the test can be carried out with compressed air.
No-no 2
Before the completion of the pipeline system flushing is not serious, the flow rate and speed can not meet the requirements of pipeline flushing. Even water pressure strength test drainage instead of flushing.
Consequences: Water quality does not meet the operation requirements of the pipeline system, which often leads to reduced or blocked pipeline sections.
Measures: use the system to set the maximum juice flow or water flow rate should not be less than 3m/s to rinse. The water color and transparency of the outlet should be consistent with the water color and transparency of the inlet water as qualified by visual inspection.
No-no 3
Sewage, rainwater, condensate pipe do not do the closed water test will do concealment.
Consequences: May cause water leakage, and cause user losses.
Measures: The closed water test should be checked and accepted strictly according to the standard. Buried underground, inside the ceiling, between pipes and other dark sewage, rainwater, condensate pipe to ensure no leakage.
Taboo 4
When the water pressure strength test and tightness test of piping system, observe the change of pressure value and water level, and check the leakage is not enough.
Consequence: Leakage occurs after piping system operation, affecting normal use.
Measures: When the pipeline system is tested according to the design requirements and construction specifications, in addition to recording the pressure value or water level change in the specified time, it is especially necessary to carefully check whether there is leakage problem.
No-no 5
Butterfly valve flange with ordinary valve flange.
Consequences: butterfly valve flange and ordinary valve flange size is different, some flange diameter is small, and the butterfly valve disc is large, resulting in can not be opened or hard to open the valve damage.
Measures: according to the actual size of butterfly valve flange flange processing flange.
No-no 6
There are no reserved holes and embedded parts in the construction of the building structure, or the size of the reserved holes is small and the embedded parts are not marked.
Consequence: WARM sanitation project construction, pick chisel building structure, even cut off the stress reinforcement, affect the building safety performance.
Measures: Be familiar with the construction drawings of heating and sanitation engineering carefully, and actively cooperate with the construction of the building structure to reserve holes and embedded parts according to the installation needs of pipelines and support hangers, with specific reference to the design requirements and construction specifications.
No-no 7
When welding the pipe, the wrong end of the pipe after the pair is not on the same Central Line, there is no gap on the pair, the thick wall pipe is not shovelled, and the width and height of the weld do not meet the requirements of the construction code.
Consequence: The wrong end of the pipe is not in a center line directly affects the quality of welding and visual quality. There is no gap between the two sides, the thick wall pipe is not shovelled, the width and height of the weld do not meet the requirements of the welding strength requirements.
Measures: After welding the pipe pair, the pipe should not be wrong, should be on a Central Line, the gap should be left on the pair, thick wall pipe should be shoVELled groove, in addition, the width and height of the weld seam should be welded according to the specification requirements.
Taboo 8
The pipe is directly buried in the frozen soil and the loose soil without treatment, and the spacing and position of the pipe piers are improper, even in the form of dry code brick.
Consequence: Due to the unstable support, the pipe was damaged in the process of backfill earth tamping, resulting in rework repair.
Measures: THE PIPELINE SHALL NOT BE BURIED IN FROZEN SOIL or UNtreated loose soil, THE SPACING OF PIERS SHALL MEET the requirements of construction specifications, AND the SUPPORT CUSHION shall be firm, ESPECIALLY at the pipe interface, which shall not BEAR shear force. The brick piers should be built with cement mortar to ensure integrity and firmness.
No-no 9
The expansion bolts used to secure the pipe supports are of inferior material, the aperture of the expansion bolts is too large, or the expansion bolts are installed on brick walls or even light walls.
Consequences: Pipe support loose, pipe deformation, or even fall off.
Measures: The expansion bolts must be selected as qualified products, and should be sampled for test inspection when necessary. The aperture of the expansion bolts should not be larger than the outer diameter of the expansion bolts. The expansion bolts should be applied to the concrete structure.
No-no 10
The flange and gasket of the pipe connection are not strong enough, and the connecting bolt is short or thin in diameter. Rubber pads are used for heat pipes, asbestos pads for cold water pipes, and double pads or bevel pads with flange liners protruding into the pipe.
Consequence: flange joint is not tight, even damaged, leakage phenomenon. The flange liner protrudes into the pipe, which will increase the flow resistance.
Measures: flanges and gaskets for piping must meet the requirements of working pressure for piping design.
The flange liner of the heating and hot water supply pipeline should be rubber asbestos pad; The flange gasket of water supply and drainage pipe should be rubber gasket.
The gasket of the flange shall not burst into the tube, and its outer round to the bolt hole of the flange is appropriate. The bevel pad or several gaskets shall not be placed in the middle of the flange. The diameter of the bolt connecting the flange should be less than 2mm than the aperture of the flange, and the length of the bolt rod protruding nut should be 1/2 the thickness of the nut.
Taboo 11
Valve installation method is incorrect.
For example, the globe valve or check valve water (steam) flow direction is opposite to the sign, the stem is installed downward, the horizontal installation of the check valve is installed vertically, the rod gate valve or butterfly valve handle is not open or closed space, the valve stem is not facing the inspection door.
Consequences: valve failure, switch maintenance difficulties, valve stem down often cause water leakage.
Measures: Install the valve strictly according to the valve installation instructions, leave the valve stem to extend the opening height, the butterfly valve fully consider the rotation space of the handle, all kinds of valve stem can not be lower than the horizontal position, let alone downward. Hidden valve not only to set up to meet the valve opening and closing needs of the inspection door, at the same time the valve stem should be oriented to the inspection door.
Taboo 12
The specifications and models of installed valves do not meet the design requirements.
For example, the nominal pressure of the valve is less than the system test pressure; When the diameter of the feed water branch pipe is less than or equal to 50mm, the gate valve is used; Hot water heating dry, vertical pipe using stop valve; The suction pipe of the fire pump uses butterfly valve.
Consequence: Affect the valve normal opening and closing and adjust resistance, pressure and other functions. Even cause system operation, valve damage forced repair.
Measures: Familiar with the application of various types of valves, according to the design requirements to select the valve specifications and models. The nominal pressure of the valve shall meet the requirements of the system test pressure. According to the requirements of the construction code: water supply pipe diameter less than or equal to 50mm should be used cut-off valve; Gate valves should be used when pipe diameter is greater than 50mm. The hot water heating dry, vertical control valve should use gate valve, fire pump suction pipe should not use butterfly valve.
Taboo 13
Do not carry out necessary quality inspection according to regulations before valve installation.
Consequences: system operation valve switch is not flexible, close loosely and water leakage (steam) phenomenon, resulting in rework repair, and even affect the normal water supply (steam).
Measure: The valve should be tested for pressure strength and tightness before installation. The test shall select 10% of the quantity of each batch (same brand, same specification, same model), and not less than one.
For the closed circuit valve installed on the main pipe to cut off the function, should be one by one for strength and tightness test. The VALVE strength and tightness test pressure shall comply with the “Construction Quality Acceptance Code for Building Water Supply, drainage and Heating Engineering” (GB 50242-2002).
Taboo 14
For the main materials, equipment and products used in construction, there is a lack of technical quality appraisal documents or product qualification certificates in line with current national or ministerial standards.
Consequences: the quality of the project is not qualified, there are hidden accidents, can not be delivered on schedule, must be reworked repair; Cause project delay, manpower and material input increase.
Measures: the main materials, equipment and products used in water supply and drainage and heating and sanitation engineering should meet the current standards issued by the state or the ministry of technical quality appraisal documents or product qualification certificate; The product name, model, specification, national quality standard code, date of delivery, name and place of manufacturer, inspection certificate or code of delivery shall be indicated.
Preparation Method of fluorine lined valve model Description of fluorine lined valve model preparation:
The fluorine lining valve model is separated from the fluorine lining part in the “Method for the Preparation of Valve Model”, and the valve model was published by the Standardization Administration recently. Proposed by the China Machinery Industry Federation, in accordance with the GB/T1.1-2009 rules to draft, valve model compilation method by the National valve Standardization Technical Committee (SAC/TC188) centralized. In line with JB/T 308-2004 editing. Fluorine lined valve model compiled the best fluorine lined valve in the market at the end of the product chaos. Fluorine lined valve model system is composed of type, drive, connection mode, structural form, lining material, nominal pressure, body material and other parameters of some road numbers and letters code composed of a purchase number, convenient sales, production, design and other use of a correct specification. The following valve in detail for you to introduce the principle of fluorine lined valve is what, the meaning of the model code.
Working principle of fluorine lined valve:
Fluorine lined valve, also known as fluorine plastic lined corrosion resistance valve, is the PTFE resin (or profiles processed) by molding (or inlaid) method in the inner wall of steel or iron valve bearing parts (the same method is suitable for all kinds of pressure vessels and pipeline accessories lining) or the outer surface of the valve inner parts, The use of its unique resistance to strong corrosive media made of all kinds of valves and pressure vessels.
Fluorine lined valve is the valve body medium can reach all the place using lining process, lining materials are generally FEP (F46) and PCTFE (F3) and other fluorine plastics, can be suitable for a variety of concentrations of sulfuric acid, hydrochloric acid, hydrofluoric acid, aqua aqua and a variety of organic acids, strong acids, strong oxidants and other corrosive media pipelines, etc. However, the fluorine lined valve is limited by the temperature (only applicable to the medium between -50℃ and 150℃). The valves that can be made of fluorine plastic are: fluorine lined butterfly valve, fluorine lined ball valve, fluorine lined globe valve, fluorine lined diaphragm valve, fluorine lined gate valve, fluorine lined plug valve, etc.