Device for sensing the contents of a fluid in a duct with a tubular body extending into the duct

• US 7,958,794 B2
• Filed: 01/05/2006
• Issued: 06/14/2011
• Est. Priority Date: 01/24/2005
• Status: Active Grant

• Current Assignee: Calectro Aktiebolag
• Original Assignee: Calectro Aktiebolag
• Inventors: Sahibzada, Jörgen, Olowson, Per
• Primary Examiner(s): Williams; Hezron
• Assistant Examiner(s): KOLB, NATHANIEL J
• Application Number:
  US11/662,647
• Publication Number:
  US 20080257011A1
• Time in Patent Office: 1,986 Days
• Field of Search: 738/64, 738/643.3, 738/634.1, 738/635.7, 738/635.1
• US Class Current: 73/866.5
• CPC Class Codes: G01N 1/2035 by deviating part of a fluid stream, e.g. by drawing-off or tapping
• CPC Class Codes: G01N 1/2247 Sampling from a flowing stream of gas
• CPC Class Codes: G01N 2001/225 isokinetic, same flow rate for sample and bulk gas
• CPC Class Codes: G01N 2001/2285 Details of probe structures
• CPC Class Codes: G01N 2015/0046 in gas, e.g. smoke
• CPC Class Codes: G01N 33/0009 General constructional details of gas analysers, e.g. portable test equipment G01N1/22 takes precedence

Abstract

A device is disclosed for sensing the contents of a fluid flowing in a duct system, such as in a ventilation duct. In at least one embodiment of the invention, the device includes a sensing element and a tubular body extending over a cross-sectional portion of the duct at issue and a supply duct with an inlet facing the main flow direction of the fluid and a discharge duct with an outlet located downstream of the inlet, to divert from the flowing fluid a partial flow which is made to pass the sensing element and then re-enter the duct. The outlet is located upstream of the downstream boundary of the tubular body.

Claims

1. A device for sensing the contents of a fluid flowing in a duct system, comprising:

a sensing element; and

a tubular body, extending over a cross-sectional portion of a duct of the duct system, including a supply conduit with an inlet facing the main flow direction of the fluid and a discharge conduit with an outlet located downstream of the inlet, to divert from the flowing fluid a partial flow which is made to pass said sensing element and then re-enter said duct, said outlet being located upstream of the downstream boundary of the tubular body, said tubular body having an outer lateral surface, the outer lateral surface having a cross-section that flares outward in the downstream direction and is approximately triangular with convex sides and rounded angles.

2. A device as claimed in claim 1, wherein the tubular body, in use, extends over the major part of the cross-section of the duct.

3. A device as claimed in claim 1, wherein the tubular body, in use, extends over essentially the entire cross-section of the duct.

4. A device as claimed in claim 1, wherein said outlet is arranged upstream of a separation point, the separation point constituting an area where the surface-parallel flow of the fluid relative to the outer lateral surface of the tubular body essentially ceases.

5. A device as claimed in claim 1, wherein said outlet is located in an area where an essentially maximum speed of the surface-parallel flow relative to the outer lateral surface of the tubular body occurs.

6. A device as claimed in claim 1, wherein said outlet is located in an area where the lateral surfaces of the tubular body relative to each other, in a direction away from said inlet, change from a divergent extent to a convergent extent relative to the main flow direction of the fluid.

7. A device as claimed in claim 1, wherein at least one of the inlet and outlet includes at least one elongate opening.

8. A device as claimed in claim 7, wherein said elongate opening has a width which is less than 5 mm.

9. A device as claimed in claim 7, wherein said elongate opening extends along the major part of the portion of the tubular body which in use is positioned inside said duct.

10. A device as claimed in claim 7, wherein said elongate opening includes a plurality of elongate openings which are spaced from each other in the longitudinal direction of the tubular body.

11. A device as claimed in claim 7, wherein the least one elongate opening is a slot.

12. A device as claimed in claim 1, wherein a section of the tubular body transversely to the longitudinal direction has a greater extent in the main flow direction of the fluid than transversely to the main flow direction of the fluid.

13. A device as claimed in claim 1, wherein said outlet includes at least two opposite openings positioned on opposite sides of the tubular body relative to the main flow direction of the fluid.

14. A device as claimed in claim 1, wherein said discharge conduit includes two duct portions which are spaced apart by a wall element, each duct portion being provided with an outlet.

15. A device as claimed in claim 1, wherein the duct system includes a ventilation duct.

16. The device of claim 1, wherein the outer lateral surface has a radius of curvature that increases between the inlet and the outlet.

17. The device of claim 1, wherein,

the tubular body has a cross-sectional width that is orthogonal to the main direction of the fluid,

the outlet being located on the tubular body at a location where the cross-sectional width is maximized.