Whooshh tubes work on the principle of pressure differentials. Once an object is inside a whooshh tube, the slippery flexible whooshh tube makes a seal around the object. A pressure differential is created across the object by either increasing the pressure behind the object (push system), or lowering the pressure in front of the object (vacuum system). This pressure differential acts on the surface of the object to create a motive force and since whooshh tubes have very low coefficients of friction the net force propels the object down the length of the tube. Whooshh tubes can be used as either push (positive pressure) or pull (vacuum) configurations depending on requirements.
The whooshh accelerator unit employs both pull and push whooshh tube configurations in one unit. Air and fish are gently pulled into the vacuum chamber of the accelerator. The air is sucked out and connected to the vacuum inlet of the air blower. The fish's momentum allows them to travel through a gentle one-way valve and enter the pressure chamber. Once the valve shuts and the fish make a seal with the primary whooshh tube, positive air flow from the outlet of the blower is introduced behind the fish thus creating the necessary pressure differential to transport them through the tube.