X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 10 Feb 2008 22:58:37 -0500 Message-ID: X-Original-Return-Path: Received: from web54404.mail.yahoo.com ([206.190.49.134] verified) by logan.com (CommuniGate Pro SMTP 5.2.0) with SMTP id 2723579 for lml@lancaironline.net; Sun, 10 Feb 2008 13:18:29 -0500 Received: (qmail 25148 invoked by uid 60001); 10 Feb 2008 18:18:28 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-ID; b=M62r4JvJg3aE+Pn8+ICv/VVZY7umHH8L/KxQ2roKqPvdRf7K8v+5sFajVqHH1FPlgPGGpsXikj+ctMnPl0ohJQU2EEsOlgbmnD5mp/hru4sqguLhny8S/w50UUD77HS2U7cAdvh7m1MtAmb9RB8mTs5e3rN0S4rpkqEzqP9Gjtw=; X-YMail-OSG: H_MLHcsVM1mX_gJDRij5JsaOBCJb2OLv7ZfI5y92CyxfkXYA3OasBqzbEkje.ZlEeD3dF4bJgXeMlwk_To_.jUwpQdP6umcyoZ.qbItvlGmhgynOZ4KDD2vl9flv Received: from [76.8.220.18] by web54404.mail.yahoo.com via HTTP; Sun, 10 Feb 2008 10:18:28 PST X-Original-Date: Sun, 10 Feb 2008 10:18:28 -0800 (PST) From: randy snarr Subject: Re: [LML] Re: 235/320/360 gear dump valve idea X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-229578275-1202667508=:24894" Content-Transfer-Encoding: 8bit X-Original-Message-ID: <650315.24894.qm@web54404.mail.yahoo.com> --0-229578275-1202667508=:24894 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Randy, like Larry, this sounds very interesting. On rare occasions I have had the same trouble raising the gear as pressure has built up on the ground due to to heat. Would you put a shuttle valve on the high side as well? I am a little fuzzy on where the shuttle valve or valves would go and how it would be oriented and plumbed. Can you take a moment and draw up a schematic of what you are thinking? That would help me a bunch probably others as well. Thanks! Randy Snarr Randy wrote: DIV { MARGIN: 0px } What happens is, the shuttle valve in the pump opens the low side when it forces fluid to the high side. This allows the fluid from the low side to pass the shuttle port and direct the fluid back to the reservoir. Then the pump pressurizes the high side and it stops, and the shuttle valve centers, which closes the low port to the reservoir and the high port to the reservoir. Here's where the problem starts. When the valve closes the low side everything is fine..... UNTIL the low side fluid expands from heat. At this point the fluid has no were to go because the shuttle valve closed. The pressure switch opens from the pressure and now you can't lower the gear until you release the pressure on the low side. Adding the extra shuttle valve, as I described should solve this problem because it can direct the expending fluid back to the reservoir without using the pumps shuttle valve. A T-shuttle valve is just a small T fitting with a ball bearing inside that rocks back and forth across two of the three ports of the T. It directs fluid one way or another way depending on the pressure flow. Works the same way as the one in pump except it won't close when the flow stops. They cost about $5. Randy Stuart LNC2 ----- Original Message ----- From: Chris Zavatson To: lml@lancaironline.net Sent: Thursday, February 07, 2008 4:43 PM Subject: [LML] Re: 235/320/360 gear dump valve idea Randy S,, et al <> I have often wondered why this is only occurring in some of our pumps, more likely the older ones. The shuttle valve in current vintage pumps requires significant force to move while the return springs on the poppet valves is very light. Perhaps something as simple as an O-ring change on the shuttle could eliminate the problem altogether with no external plumbing changes needed. Chris Chris Zavatson N91CZ 360std www.N91CZ.com --------------------------------- Looking for last minute shopping deals? Find them fast with Yahoo! Search. --------------------------------- Looking for last minute shopping deals? Find them fast with Yahoo! Search. --0-229578275-1202667508=:24894 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Randy,
like Larry, this sounds very interesting. On rare occasions I have had the same trouble raising the gear as pressure has built up on the ground due to to heat. Would you put a shuttle valve on the high side as well?
I am a little fuzzy on where the shuttle valve or valves would go and how it would be oriented and plumbed.

Can you take a moment and draw up a schematic of what you are thinking?
That would help me a bunch probably others as well.

Thanks!
Randy Snarr

Randy <randystuart@hotmail.com> wrote:
What happens is, the shuttle valve in the pump opens the low side when it forces fluid to the high side. This allows the fluid from the low side to pass the shuttle port and direct the fluid back to the reservoir. Then the pump pressurizes the high side and it stops, and the shuttle valve centers, which closes the low port to the reservoir and the high port to the reservoir. Here's where the problem starts. When the valve closes the low side everything is fine..... UNTIL the low side fluid expands from heat. At this point the fluid has no were to go because the shuttle valve closed.  The pressure switch opens from the pressure and now you can't lower the gear until you release the pressure on the low side.
Adding the extra shuttle valve, as I described should solve this problem because it can direct the expending fluid back to the reservoir without using the pumps shuttle valve.
A T-shuttle valve is just a small T fitting with a ball bearing inside that rocks back and forth across two of the three ports of the T. It directs fluid one way or another way depending on the pressure flow. Works the same way as the one in pump except it won't close when the flow stops. They cost about $5.
 
Randy Stuart
LNC2
----- Original Message -----
Sent: Thursday, February 07, 2008 4:43 PM
Subject: [LML] Re: 235/320/360 gear dump valve idea

Randy S,, et al
<<The problem is that when the pump stops the shuttle valve, in the pump, closes.>>
I have often wondered why this is only occurring in some of our pumps, more likely the older ones.  The shuttle valve in current vintage pumps requires significant force to move while the return springs on the poppet valves is very light.  Perhaps something as simple as an O-ring change on the shuttle could eliminate the problem altogether with no external plumbing changes needed.
Chris
 
 
 
Chris Zavatson
N91CZ
360std


 

Looking for last minute shopping deals? Find them fast with Yahoo! Search.

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