Freeze resistant manifold assembly and system

1. 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.

2. The freeze resistant manifold according to claim 1 , further comprising:

an O-ring disposed at an end of the plug proximal to the junction, the O-ring fitting between the plug and the inner wall of the housing;

a cap threaded portion disposed on an inner wall of the end cap;

a housing threaded portion disposed on an outer wall of the housing, the cap threaded portion mating with the housing threaded portion;

a guide rod extending from the plug towards the second end of the housing and through the witness port disposed in the end cap; and

a lock to secure the end cap to the housing.

3. The freeze resistant manifold according to claim 1 , further comprising:

wherein the end cap provides a bearing surface for the linear actuator to bear upon.

4. The freeze resistant manifold according to claim 1 , further comprising:

an O-ring disposed at an end of the plug proximal to the junction, the O-ring fitting between the plug and the inner wall of the housing; and

a stop that arrests movement of the plug at a predetermined position in the housing and prevents the O-ring from extending into the junction.

5. The freeze resistant manifold according to claim 4 , wherein the stop further comprises:

an annular bearing surface on the inner wall of the housing; and

a corresponding annular bearing surface on the plug that engages the annular bearing surface on the inner wall.

6. The freeze resistant manifold according to claim 1 , further comprising:

a first fitting disposed at a second end of a first conduit of the plurality conduits, the first fitting to connect the freeze resistant manifold to a fluid supply tank of an aircraft; and

a second fitting disposed at a second end of a second conduit of the plurality of conduits, the second fitting to connect the freeze resistant manifold to a supply line of a fixture in the aircraft.

7. The freeze resistant manifold according to claim 1 , wherein a respective central axis of each conduit and the housing intersect at a point in the junction.

8. The freeze resistant manifold according to claim 1 , wherein the plurality of conduits consists of three conduits.

9. The freeze resistant manifold according to claim 1 , wherein the linear actuator is a spring.

10. A fluid supply system for an aircraft, the fluid supply system comprising:

a fluid storage tank;

a main line to draw a fluid from the storage tank;

a first fixture;

a first supply line to supply the fluid to the first fixture;

a second fixture;

a second supply line to supply the fluid to the second fixture; and

a freeze resistant manifold comprising:

a junction to directly fluidly connect the main line to the first supply line and the second supply line; 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

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.

11. The fluid supply system according to claim 10 , further comprising:

an O-ring disposed at an end of the plug proximal to the junction, the O-ring fitting between the plug and the inner wall of the housing;

a cap threaded portion disposed on an inner wall of the end cap;

a housing threaded portion disposed on an outer wall of the housing, the cap threaded portion mating with the housing threaded portion; and

a lock to secure the end cap to the housing.

12. The fluid supply system according to claim 10 , wherein the end cap provides a bearing surface for the linear actuator to bear upon.

13. The fluid supply system according to claim 10 , further comprising:

a cap threaded portion disposed on an inner wall of the end cap; and

a housing threaded portion disposed on an outer wall of the housing, the cap threaded portion mating with the housing threaded portion.

14. The fluid supply system according to claim 13 , further comprising:

a lock to secure the end cap to the housing.

15. The fluid supply system according to claim 10 , further comprising:

an O-ring disposed at an end of the plug proximal to the junction, the O-ring fitting between the plug and the inner wall of the housing; and

a stop that arrests movement of the plug at a predetermined position in the housing and prevents the O-ring from extending into the junction.

16. The fluid supply system according to claim 15 , wherein the stop further comprises:

an annular bearing surface on the inner wall of the housing; and

a corresponding annular bearing surface on the plug that engages the annular bearing surface on the inner wall.

17. The fluid supply system according to claim 10 , wherein the linear actuator is a spring.