What is the cause of the spool vibration?
The reason for the vibration of the spool is roughly as follows: the regulator output signal is unstable. The rapid change of height and low, if the sensitivity of the valve positioner is too high, the regulator output will change slightly or drift, and it will immediately convert into a large output signal of the positioner.
Causes the valve to oscillate. The friction force of the regulating valve is too small. If the packing is too small, or the gland is not tightened, the external input signal has a slight change or drift, which will be immediately transmitted to the spool, causing the spool to vibrate and make a rattle.we are gate valve china and gate valve exporter,we can guarantee quality.
On the contrary, if the friction force of the regulating valve is too large, if the packing is installed too much, the gland is tightened too tightly, or the stuffing box is aging, and the dry stuffing is not possible when the signal is small, and the signal is generated when the signal is large. Over-the-top phenomenon causes the hysteresis oscillation of the regulating valve, and the vibration curve is approximately square wave.
In this case, the damping of the corresponding part of the regulating valve should be reduced to solve the problem, such as replacing the packing. The fluctuation of the air source causes the positioner output to fluctuate, or the movable part of the positioner is rusted and inflexible, so that the input and output signals do not correspond, and a jump oscillation occurs.
At this point, the cleaning positioner of the air supply pressure reducing valve should be opened and the moving part should be lubricated to eliminate the friction.
What are the rules for the naming of valves?
The name of the valve is named after the drive, connection, structure, lining material and type, but the following are omitted in the naming:
1)"Flange" in the connection form.
2)In the structural form:
1"Bright", "elastic", "rigid" and "single gate" of the gate valve;
2"straight-through" of the shut-off valve and the throttle valve;
3"valve" and "straight-through" of the ball valve;
4vertical valve type of butterfly valve;
5"bell roof" of the diaphragm valve;
6"plug" and "straight-through" of the plug valve;
7"straight-through" and "single-lobed" check valves;
8"Safety valve is not closed".
(3)The name of the material in the seat sealing surface material.
2valve model and name preparation method example
Example 2-1 The valve type is gate valve, which adopts electric drive, flange connection and open wedge type double gate. The sealing surface material of the valve seat is directly added by the valve body. The nominal pressure of the valve is PN=0.1MPa, and the valve body material is Gray cast iron, expressed as:
Z942W-1 is named as: electric wedge type double gate valve.
Example 2-2 The valve type is ball valve, manual, external thread connection, floating straight-through, valve seat sealing surface material is fluoroplastic, the nominal pressure of the valve is PN=4.0MPa. The valve body material is 1Cr18Ni9Ti, which is expressed as:
Q21F—40P is named as: external thread ball valve.
Example 2-3 Valve type is diaphragm valve, pneumatic normally open type, flange connection, roof type, lining material is rubber lined, valve nominal pressure and PN=0.6MPa, valve body material is gray cast iron, expressed as:
G6K41J-6 is named as: pneumatic normally open rubber diaphragm valve.
Example 2-4 The valve type is butterfly valve, hydraulic, flange connection, vertical plate type, (the sealing surface material is cast copper). The valve sealing surface material is rubber, the nominal pressure is PN=0.25MPa, and the valve body material is gray cast iron. Expressed as:
Example 2-5 Valve type is cut-off valve, electric, welded connection, straight-through, seat sealing surface material is surfacing hard alloy, working pressure at 540 ° C is 17MPa, valve body material and chrome molybdenum tantalum alloy steel, Expressed as:
J961Y-P34170V is named: Electric alloy globe valve.
Example 2-6 Valve type check valve, flange connection, swing double valve type, seat sealing surface material is copper alloy, nominal pressure is PN=1.0MPa, valve body material is gray cast iron, expressed as:
H46T-10 is named: double flap swing check valve.