Flywheel system with parallel pumping arrangement

• US 6,347,925 B1
• Filed: 06/29/2000
• Issued: 02/19/2002
• Est. Priority Date: 06/29/2000
• Status: Expired due to Term

• Current Assignee: Beacon Power (RGA Labs, Inc.)
• Original Assignee: Beacon Power Corporation (RGA Labs, Inc.)
• Inventors: Woodard, Nathan G., Rathbun, Jeremiah I.
• Primary Examiner(s): Freay, Charles G.
• Assistant Examiner(s): GRAY, MICHAEL KUHN
• Application Number:
  US09/606,724
• Time in Patent Office: 600 Days
• Field of Search: 417/51, 417/199.1, 745/72, 310/74
• US Class Current: 417/51
• CPC Class Codes: F04B 37/02 for evacuating by absorption or adsorption
• CPC Class Codes: F04B 37/08 by condensing or freezing, e.g. cryogenic pumps
• CPC Class Codes: F04D 19/044 Holweck-type pumps
• CPC Class Codes: H01J 41/12 Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps
• CPC Class Codes: H02K 7/025 for power storage
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids
• CPC Class Codes: Y10T 74/2117 Power generating-type flywheel
• CPC Class Codes: Y10T 74/2119 Structural detail, e.g., material, configuration, superconductor, discs, laminated, etc.

Abstract

A flywheel energy storage system, including a plurality of pumps arranged in parallel for simultaneously drawing-off and absorbing substantially all of the gases that evolve from a flywheel assembly during high-speed operation, is disclosed. The plurality of pumps includes at least one pump, e.g., a water sorbent, for pumping mainly water vapor; and, at least one pump, e.g., a getter pump, for pumping mainly active gases. The plurality of pumps is disposed in a gas storage chamber that is separate from the main housing of the flywheel system. A drag pump assists the plurality of pumps in the gas storage chamber by pumping the evolved gases from the main housing to the gas storage chamber for subsequent absorption by the plurality of pumps. Because the water sorbent has a relatively fast pumping speed, and the getter pump has a relatively slow pumping speed, getter material used with the getter pump degrades at a substantially slower rate, thereby reducing the cost of using the getter pump in the flywheel energy storage system.

Claims

1. A flywheel energy storage system, comprising:

a sealed housing;

a flywheel assembly disposed within the sealed housing;

a gas storage chamber disposed within the sealed housing;

a first pump disposed within the sealed housing and operatively coupled to the gas storage chamber for pumping gases that evolve from the flywheel assembly into the gas storage chamber, the evolved gases including water vapor and active gases; and

a plurality of pumps disposed in the gas storage chamber for simultaneously pumping substantially all of the gases pumped into the gas storage chamber,

wherein the plurality of pumps includes at least one pump for pumping mainly the water vapor and at least one pump for pumping mainly the active gases.

2. The flywheel energy storage system as recited in claim 1,

wherein the first pump is a drag pump.

3. The flywheel energy storage system as recited in claim 1,

wherein the pump for pumping mainly the water vapor is a water sorbent, and the pump for pumping mainly the active gases is a getter pump.

4. The flywheel energy storage system as recited in claim 3,

wherein the getter pump includes a getter housing with a constricted inlet, and getter material is disposed within the getter housing.

5. The flywheel energy storage system as recited in claim 4,

wherein the getter pump further includes a getter material storage chamber disposed within the getter housing, the getter material being disposed within the getter material storage chamber and in fluid communication with the constricted inlet.

6. The flywheel energy storage system as recited in claim 5,

wherein the getter pump further includes a heater unit operatively coupled to the getter material storage chamber for heating the getter material.

7. The flywheel energy storage system as recited in claim 4,

wherein the getter material is non-evaporable getter material.

8. The flywheel energy storage system as recited in claim 5,

wherein the getter pump further includes a void between the getter housing and the getter material storage chamber disposed therein, and an insulative material substantially fills the void.

9. The flywheel energy storage system as recited in claim 8,

wherein the insulative material is selected from the group consisting of packed glass fiber and NANOPORE™

insulative material.

10. The flywheel energy storage system as recited in claim 3,

wherein the water sorbent is selected from the group consisting of Zeolite and calcium oxide.

11. The flywheel energy storage system as recited in claim 1,

wherein the at least one pump for pumping mainly the active gases is activated to pump when associated active gas loads in the gas storage chamber approach unacceptable levels.

12. The flywheel energy storage system as recited in claim 6,

wherein the heater unit intermittently heats the getter material at times when active gas loads approach predetermined levels.

13. A method of reducing gas pressure within a flywheel housing, the method being used for reducing windage losses caused by gases evolving from a flywheel assembly disposed within the flywheel housing, the evolved gases including water vapor and active gases, comprising the steps of:

(a) pumping the evolved gases from the flywheel housing to a chamber separate from the flywheel housing; and

(b) pumping substantially all of the gases pumped into the separate chamber using a plurality of pumps disposed within the separate chamber, the plurality of pumps including at least one pump for pumping mainly the water vapor and at least one pump for pumping mainly the active gases.

14. The method of reducing gas pressure within a flywheel housing as recited in claim 13,

wherein the pumping in step (a) is performed by a drag pump.

15. The method of reducing gas pressure within a flywheel housing as recited in claim 13,

wherein the pumping in step (a) includes pumping the evolved gases from the flywheel housing to the separate chamber, the separate chamber being disposed within the flywheel housing.

16. The method of reducing gas pressure within a flywheel housing as recited in claim 13,

wherein the pumping in step (b) is performed by at least one water sorbent for pumping mainly the water vapor and at least one getter pump for pumping mainly the active gases.

17. The method of reducing gas pressure within a flywheel housing as recited in claim 16,

wherein the getter pump includes getter material disposed therein, and further including the step of applying heat to the getter material.

18. The method of reducing gas pressure within a flywheel housing as recited in claim 13,

wherein the pumping in step (a) reduces the gas pressure within the flywheel housing to a near-vacuum level while increasing gas pressure within the separate chamber to a level substantially greater than the near-vacuum level.

19. The method of reducing gas pressure within a flywheel housing as recited in claim 17,

wherein heat is intermittently applied to the getter material at times when active gas loads approach predetermined levels.

20. An apparatus for simultaneously pumping a plurality of different types of gases including water vapor and active gases, comprising:

a water sorbent; and

a getter pump, wherein the getter pump includes

a getter housing including a constricted inlet, and

a getter material storage chamber disposed within the getter housing, the storage chamber having getter material disposed therein, the getter material being in fluid communication with the constricted inlet.

21. The pumping apparatus as recited in claim 20,

wherein the getter pump further includes an insulative material disposed within a void between the getter housing and the getter material storage chamber, the insulative material substantially filling the void.

22. The pumping apparatus as recited in claim 20,

wherein the getter material is non-evaporable getter material.

23. The pumping apparatus as recited in claim 20, further including

a heater unit operatively connected to the getter material storage chamber for heating the getter material.

24. The pumping apparatus as recited in claim 21,

wherein the insulative material is selected from the group consisting of packed glass fiber and NANOPORE™

insulative material.

25. The pumping apparat us as recited in claim 20,

wherein the water sorbent is selected from the group consisting of Zeolite and calcium oxide.

26. A method of reducing gas pressure within a flywheel housing, the method being used for reducing windage losses caused by gases evolving from a flywheel assembly disposed within the flywheel housing, the evolved gases including water vapor and active gases, comprising the steps of:

(a) pumping the evolved gases from the flywheel housing to a chamber separate from the flywheel housing;

(b) continuously pumping the water vapor using at least one first pump disposed in the separate chamber; and

(c) intermittently pumping the active gases using at least one second pump disposed in the separate chamber, the at least one second pump intermittently pumping the active gases at times when associated active gas loads approach predetermined levels.