Path: utzoo!attcan!uunet!kitty!larry
From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: sci.electronics
Subject: Re: electrically operated valves
Summary: Proportional control valves...
Message-ID: <3159@kitty.UUCP>
Date: 12 May 89 01:57:17 GMT
References: <23526@shemp.CS.UCLA.EDU> <11170007@hpfcdj.HP.COM> <2011@randvax.UUCP>
Organization: Recognition Research Corp., Clarence, NY
Lines: 23

In article <2011@randvax.UUCP>, lacasse@blaise.rand.org (Mark LaCasse) writes:
> I'm not sure if washing machine, sprinkler, or other binary
> solinoid valves would suffice the original poster, but
> what I would like and can't find are PROPORTIONAL valves
> of some sort.  Something like a gate value with a stepper
> motor attached.  Something that can take water at 80 PSI.
> (Which leaves out $100 each heating system zone valves.)

	A gate valve is not usually considered to be a proportional valve.
The most common type of proportional control valves are: globe, needle,
diaphragm,  butterfly and ball.  These valves are driven by an electric
motor or by air (electrically controlled using an I/P transducer).  A
proportional control valve usually operates on a 4-to-20 mA DC signal,
although voltage inputs are available.

	Proportional control valves are not cheap; you are looking at
several hundred $$$ for a bottom-of-the-line valve (that is rated for
industrial service).

<>  Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp.
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