Patent ID: 8307848

Claim:
A freeze resistant manifold comprising: a plurality of conduits, each conduit including a respective first end in fluid communication with a respective second end; a junction defined by each of the respective first ends of the plurality of conduits being in direct fluid communication with a remainder of the first ends of the plurality of conduits; and an expansion device including: a housing having a first housing end and a second housing end, the first housing end being in fluid communication with the junction; an end cap attached to the second housing end and defining a first chamber having a witness port that vents to atmosphere; a plug disposed between the first housing end and the second housing end, the plug having a substantially fluid-tight, sliding engagement with an inner wall of the housing; a linear actuator to urge the plug towards the first housing end with a predetermined amount of force, the plug being held proximal to the first housing end by the linear actuator in response to a fluid pressure in the junction being less than a predetermined normal working pressure, the plug being moved towards the second housing end in response to the fluid pressure in the junction exceeding the predetermined normal working pressure to create a second chamber that is fluidly coupled to the first chamber after the plug moves a predetermined distance; and a guide rod extending from the plug towards the second end of the housing and through the witness port disposed in the end cap, wherein the guide rod comprises indicators for visible indication of the fluid pressure through observation of a portion of the guide rod extending outside the end cap through the witness port.