Sensor for detecting hydrocarbons

• US 20070193342A1
• Filed: 02/17/2006
• Published: 08/23/2007
• Est. Priority Date: 02/17/2006
• Status: Active Grant

• Current Assignee: Perma-Pipe, Inc. (Perma-Pipe International Holdings, Inc.)
• Original Assignee: Perma-Pipe, Inc. (Perma-Pipe International Holdings, Inc.)
• Inventors: Kubicek, Steven, Bailey, Douglas
• Granted Patent: US 7,525,444 B2
• Time in Patent Office: Days
• US Class Current: 73/53.01
• CPC Class Codes: G01N 1/405 by adsorption or absorption
• CPC Class Codes: G01N 19/10 Measuring moisture content, e.g. by measuring change in length of hygroscopic filament; Hygrometers
• CPC Class Codes: G01N 5/02 by absorbing or adsorbing components of a material and determining change of weight of the adsorbent, e.g. determining moisture content absorption bulbs B01D53/00
• CPC Class Codes: G08B 21/16 Combustible gas alarms

Abstract

A fluid sensor comprises a sensor housing, a sensor package, an actuator and a switch. The sensor package is disposed within the sensor housing and includes first and second screens and at least one sensing membrane. The sensing membrane is disposed between the first and second screens and is adapted to expand when exposed to a predetermined quantity of a first predetermined fluid. The actuator is disposed proximate the sensor package within the sensor housing and moveable between a first position and a second position through an intermediate position. The switch is disposed proximate the actuator and is operable between closed and open positions. When the actuator is in the second position at least a portion of the actuator depresses the switch to control an electrical circuit connected therewith.

Claims

1. A fluid sensor comprising:

a sensor housing defining a sensing chamber;

a first sensor package disposed within the sensor housing, the first sensor package comprising;

a sensing membrane being adapted to expand when exposed to a predetermined quantity of a first predetermined fluid;

an actuator disposed proximate the sensor package within the sensor housing, the actuator being moveable between a first position and a second position through an intermediate position; and

,

a switch disposed proximate the actuator and within the housing, the switch being operable between a closed position and an open position, wherein when the actuator is in the second position at least a portion of the actuator depresses the switch.

2. The sensor of claim 1, wherein the sensing membrane has a thickness T_o between 0.010 to 0.10 inches.

3. The sensor of claim 1, wherein the sensing membrane is adapted to dissolve when exposed to a second predetermined fluid.

4. The sensor of claim 1, wherein the sensor housing comprises a body portion and a cap removably attached to the body portion, the cap including a plurality of apertures therein.

5. The sensor of claim 1, wherein at least one vent opening is disposed proximate a bottom surface of the switch.

6. The sensor of claim 1, further comprising a sealing membrane disposed over the vent opening, the sealing membrane having hydrophobic and oleophobic characteristics.

7. The sensor of claim 1, further comprising a means for biasing the switch to one of either the open position or the closed position.

8. The sensor of claim 7, wherein the means for biasing the switch is a magnet disposed between the actuator and the switch.

9. The sensor of claim 8, further comprising a first screen and a second screen, the sensing membrane being disposed between the first and second screens.

10. The sensor of claim 9, further comprising a second sensor package disposed within the sensor housing, the second sensor package comprising:

a third screen and a fourth screen; and

,

a sensing membrane disposed between the third and fourth screens, the sensing membrane being adapted to expand when exposed to a predetermined quantity of the first predetermined fluid; and

,

an intermediate sensor membrane disposed between the fourth screen of the second sensor package and the first screen of the first sensor package.

11. A fluid sensor for detecting hydrocarbons, the fluid sensor comprising:

a sensor housing, the sensor housing defining a sensing chamber and comprising a body portion and a cap portion;

a sensor package disposed within the sensor housing, the sensor package comprising;

a first screen and a second screen; and

,

a silicone membrane disposed between the first and second screens, the silicone membrane being adapted to expand when exposed to a predetermined quantity of a hydrocarbon and having at least one aperture therein, the at least one aperture defining a fluid path through the silicone membrane;

an actuator disposed proximate the sensor package within the sensor housing, the actuator being moveable between a first position and a second position through an intermediate position; and

,

a switch disposed proximate the actuator and within the housing, the switch being operable between an open and closed position, the switch being biased to the closed position and wherein when the actuator is in the second position at least a portion of the actuator moves the switch from the closed position to the open position.

12. The sensor of claim 11, wherein the at least one aperture in the silicone membrane has a diameter D_s=0.0625 to 0.125 inches.

13. The sensor of claim 11, wherein the silicone membrane has a thickness T_o between 0.010 to 0.1 inches.

14. The sensor of claim 11, wherein the first and second screens are one of either fiberglass, stainless steel and nylon.

15. The sensor of claim 11, further comprising a means for biasing the switch to the closed position.

16. The sensor of claim 15, wherein the means for biasing the switch is a magnet disposed between the actuator and the switch.

17. The sensor of claim 11, further comprising at least one vent opening disposed proximate a bottom surface of the switch.

18. The sensor of claim 17, further comprising a sealing membrane disposed over the vent opening, the sealing membrane having hydrophobic and oleophobic characteristics.

19. The sensor of claim 11, further comprising a second sensor package disposed within the sensor housing, the second sensor package comprising:

a third screen and a fourth screen;

a silicone membrane disposed between the third and fourth screens, the silicone membrane being adapted to expand when exposed to a predetermined quantity of hydrocarbon and having at least one aperture therein permitting fluid to pass therethrough; and

,

an intermediate silicone membrane disposed between the fourth screen of the second sensor package and the first screen of the first sensor package, the intermediate silicone membrane being adapted to expand when exposed to a predetermined quantity of a hydrocarbon and having at least one aperture therein permitting fluid to pass therethrough.