Compact valve system

1 . A valve system comprising:

a housing comprising one or more apertures to permit a fluid connection between a chamber the housing is positioned within and a cavity of the housing;

a secondary valve positioned concentrically outside the housing, wherein:

when the secondary valve is in a closed position the secondary valve covers the one or more apertures to block the fluid connection between the chamber and the cavity, and

actuating the secondary valve into an open position at least partially uncovers the one or more apertures, thus opening the fluid connection between the chamber and the cavity; and

a primary valve comprising a valve seat, wherein:

the valve seat is positioned concentrically within the cavity, and

when the primary valve is in a closed position and the secondary valve is in the open position, a first axial direction-facing surface of the valve seat is positioned in a second axial direction from the one or more apertures, thus blocking a fluid connection between the chamber and a fluid routing structure positioned in the second axial direction from the valve seat.

2 . The valve system of claim 1 , wherein actuating the primary valve from the closed position to an open position comprises translating the valve seat in the first axial direction until a second axial direction-facing surface of the valve seat is positioned in the first axial direction from at least a portion of the one or more apertures.

3 . The valve system of claim 2 , wherein actuating the secondary valve and the primary valve into their respective open positions opens the fluid connection between the chamber and the fluid routing structure.

4 . The valve system of claim 1 , wherein:

actuating the secondary valve from the closed position to the open position comprises translating the secondary valve in the first axial direction until a second axial direction-facing end of the secondary valve is positioned in the first axial direction from at least a portion of the one or more apertures.

5 . The valve system of claim 4 , further comprising a spring mechanically connected to an outer wall of the secondary valve, wherein compression of the spring resists translation of the secondary valve in the first axial direction.

6 . The valve system of claim 4 , further comprising a secondary valve actuation cavity, wherein:

the secondary valve actuation cavity is bounded radially between a portion of an outer wall of the housing and a portion of an inner wall of the secondary valve;

the secondary valve actuation cavity is bounded in the second axial direction by a second portion of the outer wall of the housing;

the secondary valve actuation cavity is bounded in the first axial direction by a second portion of the inner wall of the secondary valve; and

actuating the secondary valve from the closed position to the open position comprises flowing fluid into the secondary valve actuation cavity such that pressure of the fluid pushes the second portion of the inner wall of the secondary valve in the first axial direction to cause the secondary valve to translate in the first axial direction.

7 . The valve system of claim 2 , further comprising a primary valve actuation cavity, wherein:

the primary valve further comprises a valve stem extending in the first axial direction away from a first axial-direction facing surface of the valve seat;

the valve stem extends through the primary valve actuation cavity;

the primary valve actuation cavity is bounded radially between a portion of the valve stem and a portion of an inner wall of the housing;

the primary valve actuation cavity is bounded in the second axial direction by a second portion of the inner wall of the housing;

the primary valve actuation cavity is bounded in the first axial direction by a second axial direction-facing surface of a piston, the piston mechanically connected to a first axial direction-facing end of the valve stem; and

actuating the primary valve from the closed position to the open position comprises flowing fluid into the primary valve actuation cavity such that pressure of the fluid pushes the piston in the first axial direction, thus causing the primary valve to translate in the first axial direction.

8 . The valve system of claim 7 , further comprising:

an actuation control cavity positioned in the first axial direction from the piston;

a bellows positioned in the first axial direction from the actuation control cavity; and

a plate separating the actuation control cavity from the bellows, wherein the plate comprises an orifice permitting a fluid connection between the actuation control cavity and the bellows.

9 . The valve system of claim 8 , wherein:

the actuation control cavity is bounded in the second axial direction by a first axial direction-facing surface of the piston;

the actuation control cavity is bounded in the first axial direction by a second axial direction-facing surface of the plate;

translation of the piston in the first axial direction pushes fluid in the actuation control cavity through the orifice of the plate into the bellows causing the bellows to expand; and

expansion of the bellows resists translation of the piston and primary valve in the first axial direction.

10 . The valve system of claim 1 , further comprising:

a passage permitting a second fluid connection between the chamber and the cavity;

a third valve, wherein the third valve blocks the second fluid connection between the chamber and the cavity when the third valve is in a closed position; and

one or more sensors configured to detect pressure in the chamber and pressure in the cavity respectively;

wherein, when the secondary valve is in the closed position, actuating the third valve into an open position opens the second fluid connection between the chamber and the cavity until the one or more sensors detect the pressure in the chamber and the pressure in the cavity are within a threshold differential.

11 . The valve system of claim 1 , wherein:

the chamber comprises a tank of propellant; and

the fluid routing structure positioned in the second axial direction from the valve seat provides a fluid connection to a combustion motor.

12 . A valve system comprising:

a housing comprising one or more apertures to permit a fluid connection between a chamber the housing is positioned within and a cavity of the housing;

a secondary valve positioned concentrically outside the housing, wherein:

when the secondary valve is in a closed position the secondary valve covers the one or more apertures to block the fluid connection between the chamber and the cavity, and

actuating the secondary valve into an open position at least partially uncovers the one or more apertures, thus opening the fluid connection between the chamber and the cavity; and

a primary valve comprising a valve seat, wherein:

the valve seat is positioned concentrically within the cavity,

when the primary valve is in a closed position and the secondary valve is in the open position, a first axial direction-facing surface of the valve seat is positioned in a second axial direction from the one or more apertures, thus blocking a fluid connection between the chamber and a fluid routing structure positioned in the second axial direction from the valve seat, and

actuating the primary valve from the closed position to an open position comprises translating the valve seat in the first axial direction until a second axial direction-facing surface of the valve seat is positioned in the first axial direction from at least a portion of the one or more apertures, thus opening the fluid connection between the chamber and the fluid routing structure.

13 . The valve system of claim 12 , wherein actuating the secondary valve from the closed position to the open position comprises translating the secondary valve in the first axial direction until a second axial direction-facing end of the secondary valve is positioned in the first axial direction from at least a portion of the one or more apertures.

14 . The valve system of claim 13 , further comprising a secondary valve actuation cavity, wherein:

the secondary valve actuation cavity is bounded radially between a portion of an outer wall of the housing and a portion of an inner wall of the secondary valve;

the secondary valve actuation cavity is bounded in the second axial direction by a second portion of the outer wall of the housing;

the secondary valve actuation cavity is bounded in the first axial direction by a second portion of the inner wall of the secondary valve; and

actuating the secondary valve from the closed position to the open position comprises flowing fluid into the secondary valve actuation cavity such that pressure of the fluid pushes the second portion of the inner wall of the secondary valve in the first axial direction to cause the secondary valve to translate in the first axial direction.

15 . The valve system of claim 12 , further comprising a primary valve actuation cavity, wherein:

the primary valve further comprises a valve stem extending in the first axial direction away from a first axial-direction facing surface of the valve seat;

the valve stem extends through the primary valve actuation cavity;

the primary valve actuation cavity is bounded radially between a portion of the valve stem and a portion of an inner wall of the housing;

the primary valve actuation cavity is bounded in the second axial direction by a second portion of the inner wall of the housing;

the primary valve actuation cavity is bounded in the first axial direction by a second axial direction-facing surface of a piston, the piston mechanically connected to a first axial direction-facing end of the valve stem; and

actuating the primary valve from the closed position to the open position comprises flowing fluid into the primary valve actuation cavity such that pressure of the fluid pushes the piston in the first axial direction, thus causing the primary valve to translate in the first axial direction.