[PSUBS-MAILIST] Lip seal

Thu May 21 08:17:26 EDT 2015

Alan,
Your forgetting the spring, that is what is doing the work because the pressure is the same on both sides including the areas above and in front of the v area.  The area above the V does provide pressure on the shaft IF there is a pressure differential with the higher pressure being above the V.
Hank--------------------------------------------
On Wed, 5/20/15, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Subject: Re: [PSUBS-MAILIST] Lip seal
 To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
 Received: Wednesday, May 20, 2015, 10:32 PM

 Alec is
 kind of understanding me.On the
 microscopic level, at the very point of the V where it
 touches the propeller shaft,there must
 be a slight lifting with increased pressure from depth, due
 to pressure from water & oil
 from oposing sides pushing on the V of the seal &
 squeezing it up. This lifting will occur untill the
 oil & water actually meet.This may
 cause mixing of the two with the shafts rotational
 speed. However I
 am assuming that with this simple type of rotary shaft seal,
 the oil pressure (or water depending on the seal
 orientation) which
 would be in the cavity above the spring, would counteract
 this, leaving a consistant pressure on the shaft
 regardless of depth.Alan

  From: Alec Smyth via
 Personal_Submersibles
 <personal_submersibles at psubs.org>

 To: Personal
 Submersibles General Discussion
 <personal_submersibles at psubs.org> 

 Sent:
 Thursday, May 21, 2015 11:27 AM
  Subject: Re:
 [PSUBS-MAILIST] Lip seal

 Alan, if
 the interior of the motor is in-compressible (as in liquid
 filled) there is no pressure differential. It's only the
 pressure differential that counts. There is no push
 from either side, and you could go to any pressure you like
 without the seal lifting.
 Best,
 Alec
 On Wed,
 May 20, 2015 at 5:49 PM, Alan James via
 Personal_Submersibles <personal_submersibles at psubs.org>
 wrote:

 While on the motor
 subject; a simple low pressure lip seal as below (substitute
 air side with water side)will be
 pressure compensated in a compensated motor! Is this
 correct?In oil compensation there
 will be oil pushing on the wedged shape of
 thelips
 mating surface, from one direction & water from the
 other. Eventuallythe
 pressure from both sides would lift the seal against
 it's spring pressure,but
 because of the recess above the spring that the oil gets in
 to, it  willmaintain
 the same pressure above ambient on the shaft throughout the
 depth changes.Alan

    From: Alan James via
 Personal_Submersibles <personal_submersibles at psubs.org>
  To: Personal
 Submersibles General Discussion <personal_submersibles at psubs.org>

  Sent: Thursday, May 21,
 2015 9:17 AM
  Subject: Re:
 [PSUBS-MAILIST] MK101 oil compensation tap

 Cliff,how are you compensating for oil expansion
 due to heat with the KISS method.Are you just drilling holes in the housing
 & using tube?Alan

     From: Clifford Redus
 via Personal_Submersibles <personal_submersibles at psubs.org>
  To: Personal
 Submersibles General Discussion <personal_submersibles at psubs.org>

  Sent: Thursday, May 21,
 2015 8:43 AM
  Subject: Re:
 [PSUBS-MAILIST] MK101 oil compensation tap

 Actually
 in the spirit of KISS, I am going to start out using oil
 pressure compensation.  If I run into any issues, I will
 look at using the air or this hybrid of oil and air with a
 regulator.  

 Cliff Redus

 On May 20, 2015, at 2:30 PM, Alan James via
 Personal_Submersibles <personal_submersibles at psubs.org>
 wrote:

 Jon,the alternative is to follow Hugh's idea
 that Cliff is using & I am going to test
 out,& put a regulator
 in the system that is set it to around 4psi internal
 overpressure. This means you can fill
 with oil & not worry about getting everylast drop going in, or drilling the housing. You
 will also be able to run it air compensated. There is the safety feature that if you leak oil
 there is plenty of air to replace it.Cliff already has the parts sorted, just put your
 order in:)Alan

 From: Jon
 Wallace via Personal_Submersibles <personal_submersibles at psubs.org>
  To: Personal
 Submersibles General Discussion <personal_submersibles at psubs.org>

  Sent: Thursday, May 21,
 2015 5:47 AM
  Subject: Re:
 [PSUBS-MAILIST] MK101 oil compensation tap

 How
 important is it to get every last air bubble out?  Surely a
 fraction 
 of the total volume is not going
 to result in catastrophic failure of 
 the
 motor housing, is it?

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