To refuel aircraft at the highest possible flow rate, a refueling vehicle must control the pressure accurately at the nozzle to approximately 45 psi. Because of pressure drop in the hose reel and hose, a system flowing at 300 gpm with 45 psi at the nozzle has to have a much higher pressure at the host reel inlet. But pressure drop changes with flow rate. For this reason, Venturis are used to automatically “compensate” for this pressure drop.

As velocity increases, the small opening at the center of the venturi has higher and higher velocity. As the inventor, Giovanni Venturi, discovered over 200 years ago, the pressure decreases as velocity increases. Using careful mathematics, a Venturi can create a “false signal” that can be tuned to match the actual nozzle pressure (or it may be higher in some cases, on the “safe side” with actual nozzle pressure lower). See our GamGram #32.

The primary venturi we sell is the 3” x 3” GTP-8769 venturi, made with either flanged (TTMA) or Victaulic connections. It is the highest performance 3” venturi we know of, specifically tuned for 300 gpm. We also make the GTP-8646-B 4” x 3” Venturi with Victaulic connections only.

All Gammon Technical Products venturis are cast and machined in the USA and are 356 T6 aluminum, impregnated against leakage. Rated for up to 150 psi system pressure. Needle valve not included.