X-Message-Number: 17360
Subject: VPS pt 2
From: "Lionel Vogt" <>
Date: Thu, 23 Aug 2001 10:58:14 -0400

The refrigeration units cooling ability is done through several solid state
devices known as Peltier plates. The Peltier effect was first discovered in
1834. When current passes through the junction of two different types of
conductors it results in a temperature change. Bismuth telluride is
primarily used as the semiconductor material, heavily doped to create
either an excess (n-type) or a deficiency (p-type) of electrons. They can
be operated in a vacuum or weightless environments, and in any physical
orientation. And are essentially heat pumps. Several of these units in a
cascade configuration are mounted to a cylinder made of 6061-T6 aluminum.
The peltier plates have a Hot side and a cold side, The hot side of the
peltier has a heatsink mounted on it, A series of UHMW spacers support and
outer shroud upon the cylinder that is used to guide air over the heatsinks
and draw it away from the peltiers., cold side is mounted directly to the
aluminum cylinder. Heat is pulled away from the units through the use of a
high speed Fan commonly used for cooling computer equipment (120cfm) the
surface of the aluminum cylinder is surrounded by a 1-inch thick
polystyrene insulation.  2 internal liquid circulators are also mounted
inside
The cylinder as well.) Several temperature sensors, Some are mounted using
open cell foam to make contact on the surface of the head. Others are to be
slid into the sinuses and back of the throat.

Next is a liquid heat exchanger that will be placed in the mouth and rest
against the back of the throat and pallet, this will be supported by a
pliable closed cell memory foam that is often used in the manufacture of
earplugs. After being crushed to allow its placement into the mouth, it
will expand and fill
The mouth to create an airtight seal

A neoprene rubber collar assembly seals to the cylinder with an water tight
snap seal and locking ring
The neoprene will seal around the person's neck, creating a watertight
environment once his/her head is placed into the unit

The same variety used in space helmets.

The Refrigeration unit itself contains the entire temperature sensors and
thermostat array

The batterypack for the prototype at this time is using SLA type batteries
(sealed lead acid) but they
do conform to DOT standards and are allowed to be transported onto
aircraft. The unit is a portable device with a carry handle and power
supply/charger, Gauges on the unit allow for monitoring of power output and
battery power remaining. The power supply can either convert voltages AC
110 to 220 to the 12 v needed to run the system, Or an onboard DC ? DC
converter can be used with the correct adapter from 6V to 48V DC
A lighter adapter can be used to plug it into any standard 12V DC outlet in
a car or van during transport to
extend battery life.  After reaching sustained temperature, the present
configuration of batteries allow for a runtime of 4 hours., Weight can be
lost and runtime increased by converting to NiMh (nickel Metal Hydride)
cells . However due to cost constraints of the prototype, SLAs will be used
to prove the units
Capabilities.

The liquid precooler is much like the refrigeration unit. However this unit
is smaller but contains the same number of Peltier plates as its larger
brother. Its purpose is to cool a nontoxic, water soluble gel, only
slightly thicker than water, the gel is designed to be cooled to below
freezing while still remaining in its liquid state, a connecting hose and
pump are also built into the unit that connects to a fitting on the
Refrigeration unit

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=17360