definitely useless for brewing.
they are air driven flojet brand pumps.
however, you can use them to dispense your beer. If you want to put a beer tower some distance away from your beer fridge and use a glycol chilled trunkline you will need a dispense pressure higher than 18psi and will over-carbonate your beer on straight CO2. However if you use 14-16 psi of CO2 counterpressure in your keg to deliver the beer to the pump, you can put a regulator on the CO2 or air supply to the pump and use the pump to increase your dispense pressure while maintaining an ideal pressure in the keg to maintain your carbonation level.
It's a lot cheaper to operate than custom mixed gas blends in a bottle.
This was not from a glycol chiller. The stains on the 3/8" ID vinyl tubing, and the style of the wallmount brackets with hex-nut and tailpieces at the top of the panel show that this panel was used for just the purpose that I described. This was a beer dispensing system, and these are beer pumps.
BTW.you can run multiple pumps off of 1 regulator so you just got a couple extra regulators out of the deal. Also the pumps can provide some agitation in the beer flow, so your carbonation levels and temperature need to be ON for it to work, and the pumps need to be in the fridge otherwise you will pour foam.