X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 30 [X] Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 18 Apr 2007 18:58:20 -0400 Message-ID: X-Original-Return-Path: Received: from bay0-omc2-s20.bay0.hotmail.com ([65.54.246.156] verified) by logan.com (CommuniGate Pro SMTP 5.1.8) with ESMTP id 1992132 for lml@lancaironline.net; Wed, 18 Apr 2007 13:57:30 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.54.246.156; envelope-from=randystuart@hotmail.com Received: from hotmail.com ([65.55.139.12]) by bay0-omc2-s20.bay0.hotmail.com with Microsoft SMTPSVC(6.0.3790.2668); Wed, 18 Apr 2007 10:56:19 -0700 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Wed, 18 Apr 2007 10:56:19 -0700 X-Original-Message-ID: Received: from 68.183.72.42 by BAY134-DAV2.phx.gbl with DAV; Wed, 18 Apr 2007 17:56:16 +0000 X-Originating-IP: [68.183.72.42] X-Originating-Email: [randystuart@hotmail.com] X-Sender: randystuart@hotmail.com From: "Randy" X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] Re: Gear Trouble X-Original-Date: Wed, 18 Apr 2007 10:56:16 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_010A_01C781A8.305C9090" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3028 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 X-OriginalArrivalTime: 18 Apr 2007 17:56:19.0546 (UTC) FILETIME=[DE4BF3A0:01C781E2] X-Original-Return-Path: randystuart@hotmail.com This is a multi-part message in MIME format. ------=_NextPart_000_010A_01C781A8.305C9090 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I believe the problem with just adding a relief valve would be, the = pressure shut off switch and the added relief valve could not be on the = same hydraulic circuit. To relieve the extra pressure to stop the switch = from opening would require the relief valve to open before the switch = does. In the down position this would cause the pressure switch to never = open, thus never shutting off the pump motor.=20 The ideal situation is that the lo circuit is wide open when the hi = circuit is pressurized and vise versa for the hi when the lo is = pressurized. Why the pump doesn't do this I'm not sure. Maybe it's = something in the design of the shuttle valve that causes it to close = after the pump stops on the hi side. Of course this problem wouldn't = have any effect on the lo side. The pressure differential is between the = lo and hi is wide. I'm sure there's a better fix then to crack open the = dump valve just before landing on a warm day..... Have to put some = thought to it. Randy Stuart LNC2 ----- Original Message -----=20 From: marv@lancair.net=20 To: lml@lancaironline.net=20 Sent: Tuesday, April 17, 2007 08:09 PM Subject: [LML] Re: Gear Trouble Posted for "Randy" : When opening the dump valve the pressure equalizes between the hi = and lo sides, this releases enough pressure to allow the sensor switches to = come alive. The hi and lo are still separated when the dump valve is = closed. The rising temp increases the pressures on both sides. I've seen the hi = gauge read as much as 2000 psi on a hot summer day. Randy Stuart LNC2 {Randy, I thought that the relief circuit inside the pump was designed = in such=20 a way to eliminate this possiblity. If that isn't the case, then the = addition=20 of a couple pressure relief valves set to limit the circuit pressures = could=20 solve the problem. They are readily available, McMaster Carr has = them. Go to=20 http://www.mcmaster.com/nav/enter.asp?pagenum=3D447 and scroll down to = the=20 middle of the page, where the heading is "Steel Tamper-Resistant = Adjustable=20 Relief Valves"... Just another thought to add to the mix. ] =20 =20 =20 -- For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html ------=_NextPart_000_010A_01C781A8.305C9090 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I believe the problem with just = adding a=20 relief valve would be, the pressure shut off switch and the added relief = valve=20 could not be on the same hydraulic circuit. To relieve the extra = pressure to=20 stop the switch from opening would require the relief valve to open = before the=20 switch does. In the down position this would cause the pressure switch = to never=20 open, thus never shutting off the pump motor.
The ideal situation is that the = lo=20 circuit is wide open when the hi circuit is pressurized and vise = versa for=20 the hi when the lo is pressurized. Why the pump doesn't do this I'm not = sure.=20 Maybe it's something in the design of the shuttle valve that causes it = to close=20 after the pump stops on the hi side. Of course this problem wouldn't = have any=20 effect on the lo side. The pressure differential is between the lo and = hi is=20 wide. I'm sure there's a better fix then to crack open the dump valve = just=20 before landing on a warm day..... Have to put some thought to = it.
Randy Stuart
LNC2
----- Original Message -----
From:=20 marv@lancair.net=20
Sent: Tuesday, April 17, 2007 = 08:09=20 PM
Subject: [LML] Re: Gear = Trouble

  Posted for "Randy" <randystuart@hotmail.com>:<= BR>
 =20 When opening the dump valve the pressure equalizes between the hi and=20 lo
sides, this releases enough pressure to allow the sensor = switches to=20 come
alive. The hi and lo are still separated when the dump valve = is=20 closed. The
rising temp increases the pressures on both sides. I've = seen=20 the hi gauge read
as much as 2000 psi on a hot summer = day.
  Randy=20 Stuart
  LNC2

{Randy, I thought that the relief circuit = inside=20 the pump was designed in such
a way to eliminate this = possiblity.  If=20 that isn't the case, then the addition
of a couple pressure relief = valves=20 set to limit the circuit pressures could
solve the problem.  = They are=20 readily available, McMaster Carr has them.  Go to
http://www.m= cmaster.com/nav/enter.asp?pagenum=3D447=20 and scroll down to the
middle of the page, where the heading is = "Steel=20 Tamper-Resistant Adjustable
Relief Valves"... Just another thought = to add=20 to the mix.   <Marv>   ]

  =
 =20
 

--
For archives and unsub http://mail= lancaironline.net:81/lists/lml/List.html
------=_NextPart_000_010A_01C781A8.305C9090--