Method and Apparatus for Measuring the Insect Repellent Properties of Repellant Chemicals (Patent No: 901325)

Inventor: Burton, Donald J.

Location: Vancouver, BC

Comments: N/A

Description: The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. The method of measuring the concentration of chemicals needed to produce different degrees of repellency to blood-feeding insects or other arthropods, which comprises directing for environmental purposes a stream of air maintained at a moderate temperature and a moderate relative humidity generally horizontally through a cage containing a number of said insects or arthropods, simultaneously directing for testing purposes a stream of air maintained at a higher temperature and a higher relative humidity than the environmental air temperature and humidity respectively with the environmental air through the cage, counting the number of insects or arthropods assembled in the testing air stream, injecting a chemical to be tested into the testing air stream at a known rate, and counting the number of insects or arthropods in said testing air stream during the injection of the chemical thereinto to determine the intrinsic repellency of said chemical.

2. The method as claimed in claim 1 including, without altering the temperature and relative humidity of the testing air stream, changing the rate of injection of said chemical into said testing air stream to known rates so as to ascertain the concentration of the chemical required to prevent partially or wholly the insects or arthropods from assembly in said testing air stream.

3. The method as claimed in claim 1 or 2 in which said environment air is conditioned to a temperature in the range of from about 18° to about 32°C and a relative humidity in the range of from about 25% to 60%.

4. The method as claimed in claim 1 or 2 in which the temperature of the testing air stream is in the range of from about 5° to 15°C and the relative humidity thereof is in the range of from about 10% to 30% respectively higher than the temperature and humidity of the environment air stream.

5. The method as claimed in claim 1 or 2 in which said environment air is conditioned to a temperature in the range of from about 18° to about 32°C and a relative humidity in the range of from about 25% to 60%, and the temperature of the testing air stream is in the range of from about 5° to l5°C and the relative humidity thereof is in the range of from about 10% to 30% respectively higher than the temperature and humidity of the environment air stream.

6. The method as claimed in claim 1 or 2 which includes providing a porous target in the cage and through which said stream of testing air passes, whereby said insects or arthropods in the testing air are attracted to the said target and thereby can be easily counted.

7. The method as claimed in claim 1 or 2 which includes directing both of said streams of air through a porous wall of the cage, the portion of said wall through which the testing air stream is directed forming a target to which the insects or arthropods are attracted.

8. Apparatus for measuring the concentration of repellent chemicals needed to produce different degrees of repellency to blood-feeding insects or other arthropods, comprising means causing an air stream for environmental purposes conditioned to a moderate temperature and a moderate relative humidity to pass in an approximately horizontal direction through a cage containing said insects or arthropods, means causing a smaller stream of air for testing purposes conditioned to a higher temperature and a higher relative humidity than the environmental stream to traverse the said cage in substantially the same direction as the environmental stream, means metering the rate of flow of the testing air stream, and means injecting a chemical to be tested into the testing air stream at a controlled and measured rate.

9. Apparatus as claimed in claim 8 including means for conditioning the environmental air before it enters the cage, and separate means for conditioning the testing air before it enters the cage.

10. Apparatus as claimed in claim 8 or 9 including a porous target in said cage through which said testing air stream is directed.

11. Apparatus as claimed in claim 8 or 9 including a porous wall in the cage through which both of said streams of conditioned air pass.

12. Apparatus as claimed in claim 9 in which said means for conditioning the testing air comprises heat exchange means and humidifier means, said testing air passing through said heat exchange means and said humidifier means.

13. Apparatus as claimed in claim 9 in which said means for conditioning the environment air comprises heat exchange means and humidifier means, said environment air passing through said heat exchanger means and said humidifier means.

14. Apparatus as claimed in claim 8 or 9 in which said injecting means comprises an injection syringe for directing said chemical into the testing air stream, and means for operating the syringe at different speeds to inject the chemical into the testing air stream at different rates. 15. Apparatus as claimed in claim 8 or 9 in which said injecting means comprises an injection syringe for directing said chemical into the testing air stream, and a variable speed motor operatively connected to the syringe selectively to operate the latter at different speeds to inject the chemical into the testing air stream at different rates.

16. Apparatus for measuring the concentration of repellent chemicals required to produce different degrees of repellency to blood-feeding insects comprising:
(a) a first air conditioning means for maintaining an ambient air input at a predetermined range of temperature and relative humidity:
(b) a second air conditioning means for maintaining an ambient air input at a predetermined range of temperature and relative humidity higher than said first air conditioning means:
(c) a cage for containing a supply of insects:
(d) means for directing the conditioned air output of said first and second air conditioning means in a substantially horizontal path through said cage the output of said first air conditioning means producing an environmental air stream and the output of said second air conditioning means producing a testing air stream:
(e) means for measuring the rate of flow of said testing air stream:
(f) means for injecting an insect repellent chemical into said testing air stream: and
(g) means for controlling and measuring the rate of application of the insect repellent chemical into said testing air stream.

17. Apparatus as recited in claim 16 wherein said cage has opposed porous walls to permit flow of said environmental and testing air streams through said cage.

18. Apparatus as recited in claim 17 wherein one of said porous walls upon which said testing air stream first impinges constitutes a target area for measuring effectiveness of insect repellents upon insects within said target area.

19. Apparatus as recited in claim 16 wherein said first air conditioning means comprises:
(a) air circulating means having an ambient air input;
(b) first heater means receiving the air flow from the output of said air circulating means;
(c) humidifier means receiving the air flow from the output of said first heater means;
(d) demister means receiving the air flow from the output of said humidifier means; and
(e) second heater means receiving the air flow from the output of said demister means, the conditioned air output from said second heater means constituting an environmental air stream directed through said cage.

20. Apparatus as recited in claim 16 wherein said second air conditioning means comprises:
(a) compressor means having an ambient air input;
(b) pressure regulating means connected to the air flow at the output of said compressor means;
(c) first and second heat exchanger means located within a source of heat;
(d) humidifier means located externally of said source of heat;
(e) said first heat exchanger means communicating with the pressure-regulated air flow from said compressor and said second heat exchanger means communicating with the air flow from the output of said humidifier;
(f) chamber means located externally of said cage and communicating therewith; and
(g) means conducting air flow of predetermined range of temperature and relative humidity from said second heat exchanger to said chamber means, the conditioned air output of said chamber constituting a testing air stream directed through said cage.

21. Apparatus as recited in claim 16 wherein said means for injecting an insect repellent chemical comprises:
(a) an injection syringe for directing insect repellents into said testing air stream;
(b) drive means including a variable speed prime mover, speed control means interconnecting said injection syringe and said prime mover for controlling the rate of discharge of the insect repellent from said syringe into said testing air stream; and
(c) removable coupling means receiving the needle of said syringe and connected to said testing air stream.

22. The method as claimed in claim 1 or 2 which includes providing a porous target in the cage and through which said stream of testing air passes, whereby said insects or arthropods in the testing air are attracted to the said target and thereby can be easily counted, providing means for projecting images on said target area, and selectively projecting moving and stationary images on the target area.

23. The method as claimed in claim 1 or 2 which includes providing a porous target in the cage and through which said stream of testing air passes, whereby said insects or arthropods in the testing air are attracted to the said target and thereby can be easily counted, and applying colours to said target area with the boundary defined by the impingement of said target stream.

24. Apparatus as recited in claim 18 further comprising means for selectively projecting moving and stationary images on said target area.

25. Apparatus as recited in claim 18 further comprising a colored portion of the porous wall within the boundary of the target area impinged by said testing air stream.