The selection and setting of valves are introduced

The selection and setting of valves are introduced

Principle of selection of valves for use in water supply pipelines
1. When the pipe diameter is less than 50mm, globe valve should be used. When the pipe diameter is greater than 50mm, gate valve and butterfly valve should be used
2, need to adjust the flow, water pressure should use the regulating valve, stop valve
3. Gate valves should be used where water flow resistance is small (such as water pump suction pipe)
4. Gate valve and butterfly valve shall be used on the pipe section where water flow is two-way, and stop valve shall not be used
5. Butterfly valve and ball valve should be used for small installation space
6. In the pipe section that is often opened and closed, stop valve should be used
7, the large-caliber water pump outlet pipe should use multi-function valve
(2) The position of the valve on the water supply pipeline
1. The water supply pipeline of residential district is from the leading pipe section of municipal water supply pipeline
2. The nodes of outdoor circular pipe network in residential areas should be set according to the separation requirements. If the annular pipe section is too long, segmented valves should be set
3, from the main water supply pipe in residential areas from the beginning of the branch pipe or the beginning of the household pipe
4. Indoor pipe, water meter and each branch riser (bottom of riser, upper and lower part of vertical ring pipe network riser)
5, ring pipe network branch pipe, connecting pipe through the branch pipe network
6, indoor water supply pipeline to households, public toilets, etc. from the start of the water distribution pipe, water distribution branch pipe water distribution points in 3 and more than 3 set
7, water pump outlet pipe, self-irrigation pump suction pump
8. Water tank inlet and outlet pipes and drainage pipes
9, equipment (such as heater, cooling tower, etc.) water refill pipe
10, sanitary appliances (such as large, urinal, wash basin, shower, etc.) of the distribution pipe
11, some accessories, such as automatic exhaust valve, pressure relief valve, water hammer eliminator, pressure gauge, sprinkler bolt, pressure reducing valve and reverse flow prevention device before and after
12, the water supply pipe network should be set at the lower part of the drain valve
(three) check valve selection
Check valves should be selected according to the installation position, the water pressure before the valve, the sealing performance requirements after closing and the size of the water hammer triggered when closing, etc. :
1. When the water pressure before the valve is small, swing type, ball type and shuttle check valve should be selected
2. When the airtight performance after closing is strictly required, the check valve with closing spring should be selected
3. When the water hammer is required to be weakened and closed, it is advisable to choose the fast closing silencing check valve or the slow closing check valve with damping device
4, check valve break or spool, should be able to close under the action of gravity or spring force
(4) Check valves shall be installed in water supply pipelines
Into the pipe; On the intake pipe of closed water heater or water equipment; On the water pump outlet pipe; On the outlet pipe section of the water tank, water tower and upland pool of the same pipe.
Note: check valves are not required for pipe sections with pipe backflow preventers.
(5) The position of the exhaust device for the water supply pipeline
1, intermittent use of water supply pipe network, the pipe network end and point should be set up automatic exhaust valve
2. Automatic exhaust valve or manual valve has been set at the peak point of the pipe section with obvious undulating air accumulation in the water supply network
3, air pressure water supply device, when the use of automatic air filling type air pressure water tank, the point of the water distribution network should be equipped with automatic exhaust valve
Some standards are involved in the design, manufacture and testing of valve electric devices to regulate the above work. Common standard names and codes are listed below as indexes for easy lookup. In addition, the listed standard content will be briefly introduced.
▲JB/T8528-1997 General valve electric device specification
It is the standard for valve electric devices, which came into effect in 1998-01-01. It is a revision of ZBJ16002-87 technical Specifications for electric valves. According to the design, test, inspection and application practice of electric devices in recent years, the standard has revised the working environment temperature, noise index, starting torque, maximum torque, control torque, control speed and test method of ZBJ16002-87. Its implementation will replace ZBJ16002-87.
▲GB12222-89 Multi-turn valve drive device connection
The standard is equivalent to the international standard ISO5210/1 ~ 5210/3-1982 “Multi-turn valve Driving Device connection”. It provides the connecting dimensions of the multi-turn valve drive device and the valve and the dimensions of the drive parts, as well as the reference values of torque and axial thrust. This standard applies to dimensions of connection of valve actuation devices to valves for gate, globe, throttle and diaphragm valves.
At present, the connection size and type of products of some electric device manufacturers in the world are the same as the standard. The connection size of SMC, SCD and BA products of our company conforms to this standard.
▲GB12223-89 Partial rotary valve drive device connection
The standard is equivalent to the international standard ISO5211/1 ~ 5211/3-1982 “Partial rotary valve electric Device connection”. It provides the connection size of the driving device and the valve of part of the rotary valve and the size of the driving parts, as well as the reference value of the torque. This standard applies to dimensions of connection between valve drives and valves for ball, butterfly and plug valves.
The connection size of HBC series products is different from this standard, but SMC/HBC partial rotary products can be provided according to the requirements of users. The connection size of SMC/JA products and valves can also be provided according to this standard.
▲JB/T8862-2000 Valve electric device life test specification
The standard specifies the test requirements, test items and test methods of life test of valve electric device. The life test of valve electric device type test is still carried out according to this standard. Jbz247-85 is one of the reference standards of JB/T8528-1997 “Technical conditions for Electric Valves”.
▲JB/TQ53168-99 multi-turn valve electric device product quality classification
The standard specifies the product quality grade, test method and sampling leveling method of multi-turn valve electric device. The indexes of torque repetition accuracy, life test, noise and other items are stipulated, and the quality grades of qualified products, first-class products and excellent products are stipulated.
▲JB2195-77YDF series three-phase asynchronous motors for electric valves
This standard is the first one in China on valve motor standard, it specifies the valve motor technical requirements, connection parameters, acceptance rules, etc. Limitorque motors used by SMC series have relatively higher technical parameters than YDF series (that is, SMC series does not use YDF motors), so this standard has been revised.