US Patent 7891370 Irrigation device with freeze member

An irrigation device includes a chamber having a peripheral wall made of a material susceptible to damage from the expansion of water in an interior of the chamber during freezing. A freeze member is located in the chamber and is made of a compressible material. The freeze member is configured to allow unfrozen water to pass through the chamber and to accommodate expansion of the water during freezing to prevent cracking or other damage to the peripheral wall.