From: Geary Eppley (eppley_at_physics.rice.edu)
Date: Tue May 20 2003 - 09:32:24 EDT
Hi Howard,
Thanks for the advice. We'll try to get a proper regulator for next year.
Geary
On Tue, 20 May 2003, Howard Wieman wrote:
> Hi All,
>
> It looks to me, unless someone changed it, that the regulator is basically
> not regulating and that it is set to always be open, which is fine. The
> pressure we see I would guess is just the vapor pressure of isobutane at
> what ever temperature it happens to be. I saw one number of 31 psi at 70
> deg F which is probably gauge pressure. I found a graph that shows the
> pressure will increase to 37 psi gauge at 80 degF. I'm sure that any self
> respecting pressure meter can be over pressured by a factor of 2, so I would
> not do anything (your pressure meters max scale at ~30psi gauge). The flow
> meter I understand is holding constant flow, so again no problem, but I
> don't know the recommended input pressure spec for the mass flow meter. I
> would recommend getting the correct regulator for your pressure range, both
> for the inlet bottle pressure and regulated output pressure to avoid future
> confusion. An alternative might be removing the regulator all together, but
> my guess is that this would violate the safety review you probably had to go
> through.
>
> Howard
>
> ----- Original Message -----
> From: "Geary Eppley" <eppley_at_physics.rice.edu>
> To: <hhwieman_at_lbl.gov>; <majka_at_hepmail.physics.yale.edu>
> Cc: <tofp_at_physics.rice.edu>
> Sent: Monday, May 19, 2003 4:10 PM
> Subject: Re: pressure on isob.
>
>
> > Hi Howard and Dick,
> >
> > Zhangbu is not around this week but we have two knowledgeable shift
> leaders
> > this week who could back off the gauge pressure on the TOF isobutane
> > regulator. This is not essential since I don't think the pressure can get
> > high enough to damage the gauge. We try to keep the gas pressure at about
> > one atmosphere out of the regulator. Dick I believe already knows where
> > the TOF isobutane is. It is in the rack with the TPC test gasses, just
> > toward the gas room from the TPC methane. The isobutane is a size G bottle
> > with 11 lbs of product when full. If you have a spare moment, you can back
> > off the regulator a few clicks. It can't be backed off very far since it
> > is nearly open. It will take several hours to see the pressure drop since
> > the flow rate is 3.5 ccm.
> >
> > If you don't want to fool with this, it should not make any difference.
> >
> > Cheers,
> >
> > Geary
> >
> >
> > On Mon, 19 May 2003, Geary Eppley wrote:
> >
> > > Hi Frank,
> > >
> > > I won't be back at BNL until 5/22. I don't think the pressure will get
> > > high enough to damage the gauge but if Zhangbu could reduce the pressure
> a
> > > few clicks it wouldn't hurt. This has to be done slowly and it will take
> > > several hours to see any results.
> > >
> > > Geary
> > >
> > >
> > > On Mon, 19 May 2003, Frank Geurts wrote:
> > >
> > > > Geary and/or Zhangbu,
> > > > i got a phone call from SCR: apparently the pressure of the
> > > > isobuthane(?) has gone up from 30 to 32psi and according to the
> current
> > > > shiftleader somebody told him that the pressure should not go above
> > > > 30psi. The pressure history typically is somewhere between 15-20psi.
> > > >
> > > > Zhangbu, could you at some point (or Geary if he's back from CERN)
> check
> > > > the pressure on the bottles and maybe lower it a little.
> > > >
> > > > thanks,
> > > > Frank
> > > >
> > > >
> > > >
> > >
> > >
> >
> >
> >
>
>
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