DIY Cool Suit Pump Problem

Not sure what pump I have, whatever the cheapest one at Wal-Mart was, but I had to re-do the lines and connectors so air bubbles couldn't be trapped in the pump. All lines from the pump go up at an angle with no elbows or any place else where an air bubble could be trapped. Since I did that it self-primes.

A pump of this type its designed for high flow with fairly low discharge pressure.

One way to make one work for a cool suit application is to have a bypass line from the outlet of the pump back to the tank that lets the pump move enough water to not cavitate.

Install a valve in the bypass line so you can tune it for the minimum flow to not cavitate. That will give you the highest discharge pressure to move the water through the shirt. Once the shirt is full you don't need much pressure to get the flow. This assumes running the pump at full voltage.

OR

Add a voltage regulator like this - http://www.dimensionengineering.com/DE-SWADJ3.htm

to drop the pump speed to what is needed and you will have no problem with your setup.

Thanks for all the input. I measured the flow rate on mine (through the shirt) and it changes the water out in the shirt about every 6 seconds. that is plenty. I've been playing around with a potentiometer in the circuit (the rheostat from my71 240z, only part that still works) and surprisingly it cavitates on startup regardless of how far the voltage is stepped down. I'm going to play around with the bypass ideas next. I think it will work fine in the end, just hand-wringing about reliability.

BTW here is the cooler I used. The lid screws on tight. you can turn it upside down and no leaks.

http://www.amazon.com/Cooler-5-Gallon-R … B00002ND6V

John

Instead of dumping ice in you could always fill ziplock bags with ice and then just have to swap the ziplock bags during the driver change.

We use plastic bottles frozen instead of ice. They are tied together with a cord so they can be pulled out together. No dipping and change out is rapid.

We drop the thawed bottles into a cooler of dry ice to refreeze. 6 or 7 20 oz bottles are good for over an hour of track time.

They don't freeze the water in the cooler even though they start out -110 deg. The first time you flip the switch its a rush that is hard to describe. After that it settles down to the normal level of coolness.

Hadn't tried using one. We didn't have one so I just took some 1/4" nylon cord and tied them together.

I think the cord will be a little better. Especially when freezing them. There is more slack to get the bottles positioned and in good contact with the dry ice.

Anyone using this method please be careful working with dry ice. Wear gloves. The bottles come out of the cooler cold enough to freeze your skin to them on contact if there is any moisture present.

The problem is the heat transfer is diminished with the plastic in place.  Ever notice how you can never seem to get a 20 oz soda (plastic)as cold as a 12 oz can (aluminum)?  Aluminum transfers heat better, that's why.

We freeze 2-liter and 20 oz. bottles and store them in a separate cooler with dry ice.  Before the race we cut the plastic off just leaving the blocks of ice and stuff the cooler in the car full.  We add just enough water to prime the system and it lasts about 7-8 hours.