No pump: steam bubbles in the heater tube lift slugs of hot water up the riserA one-way valve keeps the water from running back into the tankA drip machine has no pump. Cold water runs from the tank through a one-way valve into a narrow aluminium tube clamped under a 1000 W heater. The water in the tube boils, and the steam bubbles push slugs of hot water up a thin riser tube in the tower while the valve stops anything running back. At the top the water, at about 93 degrees, flows to the showerhead and drips over 75 g of ground coffee in a paper filter, and the coffee runs by gravity into the steel carafe on the hot plate. Here 1.25 litres takes about 9 minutes, played 40 times faster than life.