PROPORTIONER FOR A FIRE PROTECTION SYSTEM

A proportioner having a body portion that defines a foam passage and a fluid passage. The proportioner also includes a restrictor assembly having a restrictor disk and an orifice plate having an opening for receiving the restrictor disk. The proportioner can further include a rod member connected to the restrictor disk and a clapper assembly connected to the rod member via a sliding interface. The clapper assembly can be configured to control a flow of the foam concentrate through the foam passage in proportion to a flow of the fire protection fluid through the fluid passage by moving the rod member to vary the distance between the restrictor disk and the orifice plate. The sliding interface can be disposed between a first guide and a second guide, and at least a portion of the restrictor disk is deposed in the opening.