Straight stroke regulating pneumatic valve and the Angle of analysis on the advantages and disadvantages of pneumatic valve travel adjustment

Regulating pneumatic valve in accordance with the pneumatic valve core trajectory can be divided into straight stroke regulating pneumatic valve and Angle of pneumatic valve travel adjustment, straight stroke regulating pneumatic valve pneumatic valve core is commonly on the straight line reciprocating movement, the typical products are single-seat regulating pneumatic valve, two-seat pneumatic valve, pneumatic valve sleeve regulation, the 3-way regulating pneumatic valve, pneumatic valve Angle adjustment, etc. ; Angle of pneumatic valve travel adjustment is in commonly 90 degrees within the scope of reciprocating rotary motion, the typical products are regulating pneumatic valve, pneumatic valve, eccentric rotary pneumatic valve ( CAM flexure pneumatic valve) Pneumatic valve and plug, etc.


straight travel adjustment Angle of pneumatic valve and pneumatic valve travel adjustment, according to its structure difference, also there are many differences in use, and straight stroke regulating Angle of pneumatic valve and pneumatic valve travel adjustment performance, we compare the advantages and disadvantages of the two simple:





1, the Kv value comparison


from as shown in figure 2, straight travel flow of the medium pneumatic valve is complex, the S form, thus big flow resistance, flow capacity is small, so small flow coefficient Kv value. Pneumatic valve (angular travel See figure 3) Medium flow simple and small flow resistance, flow capacity, and wide Kv value ( The Kv value about 1 than straight travel pneumatic valve. 5 - 3 times) 。





2, prevent functional comparison


or because the straight travel pneumatic valve of complex medium flow vortex caused by the dead zone, and make the medium precipitation in throttle opening attachments, mountains, a pneumatic valve core is closed tightly, can't open it. By figure 3 shows, angular travel of medium pneumatic valve basic straight, not easy to form precipitation, prevent performance is good, so yue 'self-cleaning' performance is good.


3, the weight is


from figure 2 shows, decided by the media S sexual flow regulating pneumatic valve lumen is relatively complex, the size is larger, pneumatic valve body appearance is too complicated, pneumatic valve body size, shape and its weight is also large.


and visible in figure 3, quarter-turn pneumatic valve, because of its simple flow, lumen and shape is simple, smaller size, and weight is lighter.


4, pneumatic valve stem seal performance comparison


straight up and down stroke of the pneumatic valve pneumatic valve core, easy to take the medium out of, and thus the pneumatic valve rod sealing performance is poor. Quarter-turn pneumatic valve pneumatic valve rod rotation movement, medium is not easy to leakage, also can use better packing seal performance, make quarter-turn pneumatic valve sealing performance than straight travel 2 - Three times.


packing gland in compression deformation under tight squeeze pneumatic valve stem and produce friction of pneumatic valve stem


= F1 jf


type: j packing extrusion


f friction coefficient


for straight travel pneumatic valve, pneumatic valve stem total stress


f = F1 + F2


so need large output force actuator


diagonal stroke pneumatic valve


M = Mt + Mf


type: Mt unbalanced moment


Mf friction torque


in eccentric rotary pneumatic valve, for example,


M = Mt + Mf = FeX + F1r


type: X - — Pneumatic valve core center and the rotation center distance


R - — Pneumatic valve core shaft radius


because of X is small, r is not big, so the total torque is not big, usable output torque smaller actuators.


5, to overcome the pressure difference is


the figure 2 shows, straight travel of the single seal pneumatic valve imbalance in the pneumatic valve structure, flow situation, differential pressure is easy to open the pneumatic valve core is to allow the differential small; Pneumatic valve pneumatic valve core of the rotating angular travel, unbalanced moment for * lever 'force', because of the small arm, small torque, allow the differential ( But to the front of the pneumatic valve pressure (P1) 。

it is not hard to see from the above aspects, straight Angle of pneumatic valve and pneumatic valve travel adjustment travel adjustment each have their own advantages and disadvantages, we can combine the above several aspects during the selection of choice.




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