I am working on a project where I have to do procurement assistance for choke valve with a linear and stepper actuator. I am not able to convince myself on how does it work. And I searched some vendor sites on this topic, but I found information about either a linear actuator or a stepper type, but not both as a single entity. Can anybody help me understand why such arrangement is required and how does it work..
In reading your post, I take it that you want to know how a stepper linear actuator works and the arrangement of it? If that is correct I do have some information listed below. I hope it helps.
A stepper linear actuator is a mechanical device which produces force, as well as motion along a straight path. A stepper linear actuator motor uses the essence of a stepper motor but with some slight modifications. The shaft of a normal stepper motor is replaced with a precision lead screw and the rotor is replaced with a threaded precision nut. As the rotor rotates, the lead screw rotates inside the precision nut allowing for linear motion to occur. Minimizing outside mechanical systems to convert rotary into linear motion, greatly simplifies rotary to linear applications. This design allows for high resolution and accuracy and minimizes extra mechanical components.
Hi Mr. Shak,
Thanks for replying to my thread with some useful information, however I have one more question as to whether this is used in the choke valve for actuation? I visited the website you mentioned, I found that those gearboxes are used in servo motors, stepper motor, AC & DC motors and valve actuation was not mentioned.
One more info, it is actually getting a 4-20mA AO signal, by using E/H converter it has to be converted into step signals to open/close the choke valve in steps, that's why I mentioned it as a linear and stepper actuator.
Hope now I am clear in conveying my doubt..
If you know any info on this matter please throw some light on it...
The only choked flow stepper motor valve that I know of is produced by Woodward. See http://www.woodward.com/gasvalvesswift.aspx?cf03800514=148FD13A8!MjA0MDU4NjE1OmNvcnByYWRpdXNzc286rNpIH5CgKs4TIAAfY8awGQ==. If the link doesn't work search Woodward Swift Gas Metering Valve. It is used on smaller turbines <1.5 MW. There are a number of benefits to this system and you may want to contact Woodward for more information. Note: I do not work for Woodward. I am just familiar from this program from a previous project I was on.