Exterior gear transfer pump The VT pumps are manufactured in several sizes. The resistant pump is capable of pumping nearly all pumpable media up to a viscosity of 80,000 cP. A tempering of the pump can optionally be done via the back-lit heating chamber. As a general rule, the speed is determined by the viscosity or the lubricity of the medium, wherein speeds up to 1.500 n / 900 n max. are usually used for VT pumps.