Description: height of the centre of the exhaust pressure gauge; Name: height of exhaust pressure gauge 
Description: Height of the zero or centre position of the outlet manometer, or other point as defined by the manometer calibration ; Name: Height of the outlet manometer
Description: average speed given by the stroke length multiplied with the number of complete pumping cycles of the piston, plunger or piston attached to the diaphragm per minute (stroke per minute or pump crank speed); Name: piston velocity