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From the Oildyne 108 spec sheet,
Thermal Relief Valves? - Why?
The thermal relief valve?s (TRV) purpose is to allow a
bleed
off of built up pressure due to thermal expansion
of the fluid or to act as a
(limited) shock load protection,
should a cylinder in the system get
bumped.
The thermal relief valve is included in circuits using
a pilot
operated check valve. The single direction
units get one; the reversing units
get two. It is located
between the check valve and the 108 Series
pump
outlet port. It is a fixed relief valve with a pressure
setting
approximately 100-140 bar (1500-2000 psi)
above the system relief valve
pressure.
Wolfgang
----- Original Message -----
Sent: Monday, January 30, 2012 8:51
PM
Subject: Re: [LML] Re: Hydraulic
hoses
To follow-up: Our thermal pressure relief valve is nominally 2,500
psi. It will open somewhere between 2,500 to 2,900 psi.
Chris Zavatson
N91CZ
360std
Lorn, et al
Rob is referring to the
system downstream of the poppet valve. It is true that the pump and
the adjustable relief valve will not allow the system to actively pressurize
beyond the the relief valve setting. However once shut down, thermal
heating can further raise the pressure level on the aircraft side.
There is a fixed thermal relief valve in the pump downstream of the
poppet valve for just such a reason. I do not know what its setting
is. It is definitely greater that 2,000 psi. Given that the
Oildyne pumps are rated to 3,000, I would not be surprised if the thermal
relief valve rating is greater than 3,000 psi.
Chris Zavatson
N91CZ
360std
Rob, If the hydraulic pump is
working correctly, it has a 1,400 to 1,500 PSI override. The pressure in
both the up and down side will never be greater than the override
PSI. Lorn > From: "Stevens Family" < stevens5@swiftdsl.com.au> >
Date: January 29, 2012 5:16:11 PM EST > > A quick query from
?Down Under?. I am up to building the hydraulic system for my Lancair 360,
and need to purchase some hydraulic hose for the gear retract system. I
understand the system theoretically operates at about 1500 PSI. However I
have spoken to someone with experience on a similar aircraft, and he said
that he has observed pressures over 2000 PSI, due to the heat soak
phenomenon previously discussed on the LML. > > My question is,
what pressure hose have others used in their aircraft? Do you have any
suggestions or useful comments about building this system? > >
Thanks in anticipation. > > Rob Stevens > Perth, Western
Australia. -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html
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