Constant volume air flow rate control for animal cage rack ventilation system

• US 6,457,437 B1
• Filed: 10/26/2000
• Issued: 10/01/2002
• Est. Priority Date: 10/26/2000
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Frasier, Daniel P., Tassini, Steve, Sharp, Gordon P.
• Primary Examiner(s): Jordan, Charles T.
• Assistant Examiner(s): SHAW, ELIZABETH ANNE
• Application Number:
  US09/697,275
• Time in Patent Office: 705 Days
• Field of Search: 119/417, 119/418, 119/419, 119/452, 119/455
• US Class Current: 119/419
• CPC Class Codes: A01K 1/031 Cages for laboratory animals; Cages for measuring metabolism of animals

Abstract

A rack system for holding a number of individual drawers or cages for laboratory or other animals has a plenum array for providing fresh air and removing stale or contaminated exhaust air from the drawers. A constant volume inlet valve and a constant volume outlet valve provide for stable air flow within each individual drawer while the exhaust air is expelled to a low pressure exhaust duct.

Claims

1. In a animal holding system of the type having a rack having a plurality of openings, each opening for receiving at least one drawer for at least one animal, each said drawer having a plurality of walls and a floor defining a holding space for the animal, at least one of said walls having an inlet for receiving air from an inlet plenum of the rack, said drawer having an outlet for routing air from the holding space to an outlet plenum of the rack for connection to an exhaust system, said rack having a plurality of docking stations, each station configured to mate one drawer'"'"'s inlet to the inlet plenum and one drawer'"'"'s outlet to the outlet plenum, said system including:

a) a constant volume inlet valve for connection to a fresh air source, and providing fresh air from the source to the inlet plenum; and

b) a constant volume outlet valve receiving air from the outlet plenum, for connection to a low pressure exhaust duct.

2. The system of claim 1 wherein the inlet and outlet valves are each adjustable for a preselected volume rate of flow.

3. A method for using the system of claim 2, comprising the steps of

a) adjusting the inlet valve to a preselected volumetric flow rate; and

b) adjusting the outlet valve to a preselected volumetric flow rate substantially greater than the inlet valve'"'"'s flow rate.

4. The method of claim 3, including the step of adjusting the outlet valve'"'"'s volumetric flow rate to a value approximately two to three times the volumetric flow rate of the inlet valve.

5. The system of claim 2, wherein each valve is a self-actuating, venturi-type, constant volume flow control valve with a spring-controlled throttling element.

6. A method for using the system of claim 2, comprising the steps of

a) adjusting the inlet valve to a preselected volumetric flow rate;

and

b) adjusting the outlet valve to a volumetric flow rate greater than the inlet valve'"'"'s flow rate.

7. The method of claim 6, including the step of adjusting at least one of the inlet and outlet valves to create a volumetric flow rate through the outlet valve at least two times the volumetric flow rate through the inlet valve.

8. The system of claim 1, wherein each valve is a self-actuating, venturi-type, constant volume flow control valve.

9. The animal holding system of claim 1 including a blower providing pressurized air to the inlet valve.

10. The animal holding system of claim 9 including an air filter interposed between the blower and the inlet valve.

11. In a animal holding system of the type having a rack having a plurality of openings, each opening for receiving at least one drawer for at least one animal, each said drawer having a plurality of walls and a floor defining a holding space for the animal, at least one of said walls having an inlet for receiving air from an inlet plenum of the rack, said drawer having an outlet for routing air from the holding space to an outlet plenum of the rack for connection to an exhaust system, said rack having a plurality of docking stations, each station configured to mate one drawer'"'"'s inlet to the inlet plenum and one drawer'"'"'s outlet to the outlet plenum, said system including:

a) a fan for providing fresh air to the inlet plenum; and

b) a constant volume outlet valve receiving air from the outlet plenum, for connection to a low-pressure exhaust duct.

12. The system of claim 11 wherein the outlet valve is adjustable for a preselected volume rate of flow.