×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Flow Gain of a spool valve

Flow Gain of a spool valve

Flow Gain of a spool valve

(OP)
When looking at a flow gain graph flow vs input voltage. If pressure can vary the gradient of the plot i.e higher pressure equals sharper increase in flow. What can vary the curve at the top of the plot when the flow reaches its rated flow. Is this the spool charictaristics and/or the drive amplifier?

A Ledson.CSWP (when it was hard!)

RE: Flow Gain of a spool valve


I am not quite sure I am catching your question, please correct and specify if I am wrong!

If you are talking about a proportioonal operated solenoid valve, or a similar valve where flow is proportional to a regulating signal, for instance a signal in range 0-20mA, you have to divide between the operating signal (0-20mA) and the necessary operating force to balance the opening.

The necessary force is proportional to the opening degree (0-20mA) but also proportional to the pressure for a direct operated proportional valve. Higher liquid pressure will give higher necessary force at a given opening.

(If you have a balanced operating valve the force is more constant, but anyway you need to change and balance the opening degree)

Most often the input fluid pressure to the valve is kept (relatively) constant, and you use the operating signal to give (balance)an opening.

The valve will then give a (relatively) constant flow at a given opening. If you change the input signal, you change the opening and hence the flow proportionally.

The valve is balanced at this opening internally by an internal position signal, given from the piston position, compared to the incoming operating signal.

If you have this valve construction and increases the incoming pressure, the flow will increase, if the ingoing operating signal and everything else is kept constant.

To lower the flow to the wished flow value you need extra force to balance the pressure, keeping a somewhat smaller opening.

For such cases you need your input operating signal to the valve to change (increased force, lesser opening) until correct flow is obtained.

You can obtain this by making the input operating signal as a processed result from a flow measuring or pressure measuring device downstream the valve.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources