Plastic sub-catchment and the valve device works in the application of warm (e)

1.5.2 Torque Test



Manual valves should be under the nominal pressure and temperature conditions, in accordance with the standard provisions of state regulation of torque to operate after the test, and gives full-or all-valve clearance of the maximum allowable operating torque value.



The numerical accuracy by processing components and the impact of fluctuations in a larger assembly.



1.5.3 the requirements of operation allows the force



Plastic circular valve handle or hand wheel clearance with the full force.



1.5.4 Connection Size



A) end - end-size



Flange connection system with the valve face - face size should be selected the following criteria:



-PN flange design see EN558-1;



-Class design, see the flange EN558-2.



Other types of end connections should be identified manufacturers face - face size.



B) the valve end connection size



Flange connection to connect the valve size should meet the following criteria:



-PN flange design see EN1092-1;



-Class design, see the flange prEN1759-1: 1997.



Valve end connections shall be in accordance with the thread size ISO7-1 or ISO228-1.



1.5.5 plastic valves and piping system to connect the way



Welded connection: diameter of the valve to connect the site with the same diameter pipe, valves and pipes to connect parts of the end face relative to welding;



Bonded socket connection: parts of valves for the jack to connect the form with the tube connected to bonding;



Fused Socket connection: diameter of the valve to connect the site for the laying of electric wires for the mouth of the form fused with the pipe to connect to;



I melt for connection: the valve connection mouth for parts for form, with the tube socket to connect to hot-melt;



Bonded Socket connection: the valve connecting the site to the mouth for the form of bonding with the tube socket to connect;



Rubber ring Socket connection: connect the valve inner parts of the rubber ring set for oral forms, with the tube socket to connect;



Flange connections: flange valve connecting the site to form the flange and pipe to connect;



Thread: the valve connecting the site for the thread form, with the tube or pipe fittings to connect the thread;



Then connect the living: the valve connecting the site to take the form of live, and tube or pipe fittings to connect.



At the same time a valve can have a different connection.



1.6 the use of plastic valve pressure and temperature



With the temperature increase in the use of plastic in order to shorten the life of the valve. In order to maintain the same life, we need to reduce the use of pressure. Table 2 gives the level of body temperature coefficient material fr.



2. Problems of



2.1



Plastic sub-catchment device main part of the whole plastic products and plastic products in two parts, and some plastic products to the attention of metal and plastic parts of the bond strength and sealing reliability.



2.2 plastic pipe and plastic valve nominal size, nominal pressure manner inconsistent tagging. Plastic pipe with a nominal size dn said valves with nominal size DN said; for hot and cold water mark of the plastic pipe does not allow Nominal pressure PN, Mark Pipe Series S-level under the conditions of use choose to use the pressure and the plastic valve Nominal pressure is marked PN, with the temperature levels to choose fr coefficient temperature.



2.3 in the international standards does not require different specifications for the size of valve torque, given only the length of the handle (or hand wheel diameter) and force requirements, we can not guarantee the quality of the torque valve products, as producers can increase the length of a long handle (or hand wheel diameter) failed to make the goods into a qualified product.



2.4PP-H designed for бs stress 5MPa, some international materials have been designed to бs stress 6.3MPa or 8MPa, strength in the design of choice of raw materials compared with other varieties in terms of some conservative.



2.5



Necking of the smallest valve diameter did not give a minimum size of different specifications of quantitative requirements, only to indicate the manufacturer. This makes the valve manufacturers necking some products that have too much relative products with the specifications it is compact, but it will result in increased resistance to local pipeline system. Necking Path smallest size valve metal valve in the standard provisions.



3. Conclusion



As long as the choice of raw materials and product control are in accordance with the relevant international standards and requirements of national standards, sub-catchment of plastic valves and plastic device is fully capable to meet to warm the use of plastic piping system requirements. 

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