Evidently, there are probably a dozen types of valves out there, and
so is the case for valve actuators as well. Once there is a valve, there must
be a means of controlling or operating it and there are quite a few options,
which include levers, hand wheels and gears. However, in order to make operating
a valve stress-free and overcome the need for direct human interactions, valve
actuators are much more preferred. Having the luxury of remote and automatic
https://www.kp-lok.com/product/purge-valves/ operation that valve actuators offer is quite important in cases of emergencies
as their shutdown mechanisms can reduce the need for humans to be involve in
these dangerous situations.
In order to categorize valve actuators into different types, first, we
have to know their mode or type of operation. Majorly, there are two types of
valve operation:
·
Rotary or Quarter-turn
operation – it is generally easier to fit the right
actuator to these types of valve and the operation is quite simple; it only
requires a 90-degree rotation at the appropriate torque. Valves in this
category includes ball, plug and butterfly valves. Quarter-turn dampers may
also fall into this category.
·
Multi-turn operation – valves in this category have either non-rising rotating stems or
rising non-rotating stems and multiple turns are required to open or close
these valves. They include knife gates, globe valves, gate valves and sluice
gates.
After knowing this, we can easily group valve actuators into a few
categories based on the power applied and type of movement:
·
Pneumatic and hydraulic (fluid
power) actuators (quarter-turn):can be used where
electric power isn’t available and for applications that prioritize simplicity
and reliability. They turn linear motion into quarter-turn motion required to
operate the valve.
·
Pneumatic and hydraulic (fluid
power) actuators (multi-turn): mostly used in
situations where multi-turn output is required to operate a linear-type valve
and where electrical power isn’t available.
·
Electric actuators
(multi-turn): common, dependable, capable of
operating very large valves quickly and powered by a single or three-phased
electric motor.
·
Electric actuators (quarter-turn): similar to multi-turn electric actuators, offers 90 degrees
rotation and most suitable for smaller valves.
·
Manual actuators: use wheels, levers and/or gears to enable movement.
Now that we know the basic types of valve actuators, the next thing
to know is how to choose one. There are several factors to consider before
choosing an actuator, here are a few:
Usage Factors
These factors are very important to consider before choosing an
actuator. Taking time to go over these factors will help ensure that you choose
the perfect and safest actuator for the job. These factors include
compatibility, temperature range and working environment (hazardous, toxic or
safe).
Force And Size
Before choosing an actuator, you need to consider the amount of force
required to operate it. Will it be linear or rotary? Also, the size, design and
differential pressure across the valve must be considered before choosing a
valve actuator.
Speed
The power requirements of a valve depends on its speed of operation.
Knowing the speed and power required will greatly help you to choose the
perfect actuator for the valve.
Safety And Cost
It is important to know the type of environment of the valve before
choosing an actuator. This will ensure that you do not pick the wrong actuator.
An actuator designed to be used in a safe environment might cause problems if
used in a hazardous environment. Also, it is very important to consider your
budget before choosing an actuator. However, you should prioritize quality and
reliability while choosing.
Conclusion
Valve actuators are designed to make operating a valve a very easy
and stress-free task. There are quite a few types of actuators and a few
factors to consider before choosing one. Knowing these factors will help you
choose the right one and prevent problemsthat may come from choosing a wrong
one.
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