Poppet valve with diverging-converging flow passage and method to reduce total pressure loss

1. A poppet valve, comprising:

a valve body, said valve body having a central axis, a flow inlet, and a flow outlet;

a poppet guide disposed inside the valve body so as to form a first portion of a flow passage from the flow inlet to the flow outlet, said flow passage being formed between an inside surface of the valve body and an outside surface of the poppet guide and passing through at least one hole in the poppet guide;

a poppet shutter disposed inside the poppet guide so as to form a second portion of the flow passage between an outside surface of the poppet shutter and the inside surface of the valve body; and

a converging-diverging flow passage formed by a portion of an outer surface of the poppet shutter and a corresponding portion of an inner surface of valve body,

wherein the converging-diverging flow passage includes (i) a convergent portion, (ii) a minimum area portion, and (iii) a divergent portion.

2. The poppet valve according to claim 1 , wherein, when the poppet valve opens, a total pressure loss in the flow through the converging-diverging passage initially increases when the poppet shutter is close to the valve body and reduces as the poppet shutter moves further away from the valve body as the valve continues to open.

3. The poppet valve according to claim 2 , further comprising:

a biasing member disposed inside an inner chamber of the poppet guide, said biasing member being configured to bias the poppet shutter toward an inside surface of the flow inlet so as to block the flow passage.

4. The poppet valve according to claim 3 , wherein the converging-diverging flow passage is located at an edge of the poppet shutter adjacent to a location where the poppet shutter seats against the valve body when the poppet valve is closed.

5. The poppet valve according to claim 3 , wherein the converging-diverging flow passage is located axially downstream from an edge of the poppet shutter adjacent to a location where the poppet shutter seats against the valve body when the poppet valve is closed.

6. The poppet valve according to claim 2 , further comprising:

a purge flow passage configured to place an inner chamber of the poppet guide in flow communication with a region of low static pressure of the flow passage.

7. The poppet valve according to claim 6 , wherein the region of low static pressure is the minimum area portion of the converging-diverging flow passage.

8. The poppet valve according to claim 6 , wherein the region of low static pressure is the at least one hole in the poppet guide.

9. The poppet valve according to claim 8 , wherein the purge flow passage is inclined with respect to the central axis of the valve body.

10. The poppet valve according to claim 9 , wherein an inclination angle of the purge flow passage varies between 10 and 25 degrees.

11. The poppet valve according to claim 10 , wherein the inclination angle is approximately 19 degrees.

12. The poppet valve according to claim 9 , wherein a ratio of a diameter of the at least one hole to a diameter of the flow inlet ranges from about 0.36 to about 0.44.

13. A hyper compressor comprising a poppet valve that includes:

a valve body, said valve body having a central axis, a flow inlet, and a flow outlet;

a poppet guide disposed inside the valve body so as to form a first portion of a flow passage from the flow inlet to the flow outlet, said flow passage being formed between an inside surface of the valve body and an outside surface of the poppet guide and passing through at least one hole in the poppet guide;

a poppet shutter disposed inside the poppet guide so as to form a second portion of the flow passage between an outside surface of the poppet shutter and the inside surface of the valve body; and

a converging-diverging flow passage formed by a portion of an outer surface of the poppet shutter and a corresponding portion of an inner surface of valve body,

wherein the converging-diverging flow passage includes (i) a convergent portion, (ii) a minimum area portion, and (iii) a divergent portion.

14. A poppet valve, comprising:

a valve body, said valve body having a central axis, a flow inlet, and a flow outlet;

a poppet guide disposed inside the valve body so as to form a first portion of a flow passage from the flow inlet to the flow outlet, said flow passage being formed between an inside surface of the valve body and an outside surface of the poppet guide and passing through at least one hole in the poppet guide;

a poppet shutter disposed inside the poppet guide so as to form a second portion of the flow passage between an outside surface of the poppet shutter and the inside surface of the valve body;

a biasing member disposed inside an inner chamber of the poppet guide, said biasing member being configured to bias the poppet shutter toward an inside surface of the flow inlet so as to block the flow passage;

a converging-diverging flow passage formed by a portion of an outer surface of the poppet shutter and a corresponding portion of an inner surface of the valve body; and

a purge flow passage configured to place an inner chamber of the poppet guide in flow communication with a minimum area portion of the converging-diverging flow passage,

wherein the converging-diverging flow passage includes (i) a convergent portion, (ii) the minimum area portion, and (iii) a divergent portion.

15. The poppet valve according to claim 14 , wherein, when the poppet valve opens, a total pressure loss in the flow through the converging-diverging passage initially increases when the poppet shutter is close to the valve body and reduces as the poppet shutter moves further away from the valve body as the valve continues to open.

16. The poppet valve according to claim 15 , wherein the converging-diverging flow passage is located at an edge of the poppet shutter adjacent to a location where the poppet shutter seats against the valve body when the poppet valve is closed.

17. A hyper compressor comprising a poppet valve that includes:

a valve body, said valve body having a central axis, a flow inlet, and a flow outlet;

a poppet guide disposed inside the valve body so as to form a first portion of a flow passage from the flow inlet to the flow outlet, said flow passage being formed between an inside surface of the valve body and an outside surface of the poppet guide and passing through at least one hole in the poppet guide;

a poppet shutter disposed inside the poppet guide so as to form a second portion of the flow passage between an outside surface of the poppet shutter and the inside surface of the valve body;

a biasing member disposed inside an inner chamber of the poppet guide, said biasing member being configured to bias the poppet shutter toward an inside surface of the flow inlet so as to block the flow passage;

a converging-diverging flow passage formed by a portion of an outer surface of the poppet shutter and a corresponding portion of an inner surface of the valve body; and

a purge flow passage configured to place an inner chamber of the poppet guide in flow communication with a minimum area portion of the converging-diverging flow passage,

wherein the converging-diverging flow passage includes (i) a convergent portion, (ii) the minimum area portion, and (iii) a divergent portion.

18. A method for reducing a closing pressure force acting on a poppet shutter of a poppet valve, said poppet valve having a valve body with a central axis, a flow inlet, and a flow outlet, said poppet valve including further a poppet guide and a biasing member configured to bias the poppet shutter disposed inside the poppet guide against the valve body so as to close the poppet valve, the method comprising:

as the valve starts to open and the poppet shutter is located near a seating surface of the valve body, increasing the total pressure loss at the location of a converging-diverging flow passage formed by a portion of an outer surface of the poppet shutter and a corresponding portion of an inner surface of the valve body so as to increase a force acting on the poppet shutter to cause the valve to open; and

as the valve continues to open and the poppet shutter moves further away from the seating surface, decreasing the total pressure loss as a throat area of the converging-diverging flow passage increases,

wherein the converging-diverging flow passage includes (i) a convergent portion, (ii) a minimum area portion, and (iii) a divergent portion.

19. The method according to claim 18 , further comprising:

placing an inner chamber of the poppet guide in flow communication with a region of reduced static pressure of the converging-diverging flow passage so as to reduce a fluid pressure force acting on an inner surface of the poppet shutter toward an inner surface of the valve body to cause the poppet valve to close.

20. The method according to claim 18 , further comprising:

placing an inner chamber of the poppet guide in flow communication with a region of reduced static pressure in a flow from the inlet to the outlet of the valve so as to reduce a fluid pressure force acting on an inner surface of the poppet shutter toward an inner surface of the valve body to cause the poppet valve to close, said region of reduced static pressure being located at a region of acceleration in the flow from the inlet to the outlet as the same passes through a hole in the poppet guide.