The magnetic force exerted by the magnetic field on a moving charge has also led to the development of a pumping device without any moving parts, commonly referred to as electromagnetic pumps. The only thing that moves in this device is the liquid itself that is to be circulated from one place to another. The pumps consist of a channel, which is placed in a magnetic field that carries liquid metal or blood, depending upon its application. When a current is passed in the transverse direction the resulting magnetic force drives the liquid along the channel.
Fire Curtain Winch is used to raise and lower fire curtains. A hydraulic speed regulator controls its lowering speed. It has hand crank or motorized versions. The curtain is held in place by a caliper disk brake or clutch held engaged by the fire line.