Garbage Disposal

Overview

A garbage disposal is a motor-driven grinder fitted under a kitchen sink that breaks food scraps into a slurry fine enough to wash down the drain. This is a continuous-feed unit, the common residential type: you flip a switch and feed scraps in while the motor runs, rather than loading a batch and capping it first.

The whole machine hangs from the sink. The Mounting Assembly clamps to a flange dropped through the drain opening, so the only support is that three-bolt ring. Below the clamp sits the Housing & Shell, a two-piece shell whose upper half forms the grinding chamber and whose lower half covers the motor. A rubber Baffle / Splash Guard caps the throat to block splash-back and dampen noise, and a knock-out Dishwasher Inlet lets a dishwasher drain through the same grinder.

How it works

Unlike a blender, a disposal has no blades. The Induction Motor spins a vertical shaft that turns the Grinding Assembly. At its heart is a steel turntable, or flywheel, carrying two swivelling impeller lugs. As the flywheel spins, centrifugal force throws scraps outward against a fixed, toothed grind ring lining the chamber wall. The lugs are not sharp; they pin and smear the waste against the ring's teeth, which shear it into particles small enough to pass with the running water. The lugs swivel so a hard object jams them outward rather than stalling the motor.

The 1/2 HP single-phase induction motor is direct-coupled to the flywheel and started by a capacitor. Because jams are routine, a push-button thermal overload trips and cuts power before the windings cook; pressing the reset restores it once the obstruction clears. The motor runs near 1,725 RPM and rides on two shaft bearings with a seal between the wet chamber and the dry motor cavity.

Ground slurry leaves through the Discharge Outlet elbow at the chamber's base and drops into the P-trap and house drain. The motor energizes through the Switch & Control Board, typically a wall switch or a counter-top air switch, and rubber isolation feet on the shell keep grinding vibration out of the sink.