WO2019232587A1

WO2019232587A1 - Flow meter and flexible duct including a flow meter

Info

Publication number: WO2019232587A1
Application number: PCT/AU2019/050585
Authority: WO
Inventors: Remy Bourcier; Daniel Vincent Stack
Original assignee: Minetek Investments Pty Ltd
Priority date: 2018-06-07
Filing date: 2019-06-06
Publication date: 2019-12-12

Abstract

There is disclosed a flexible duct arrangement (10) including a flow meter (12) and a flexible duct (14). The flow meter (12) includes a pressure sensor (16), a substantially flexible elongate body (18) arranged to be supported between opposing sides (21) of the flexible duct (14) and flexible conduits (20) extending between the elongate body (18) and the pressure sensor (16). The elongate body (18) includes an upstream hollow tube (22) and a downstream hollow tube (24) each adapted to respectively communicate air at the upstream and downstream sides (26a, 26b) of the elongate body (18) with the pressure sensor (16) via the flexible conduits (20).

Description

Flow Meter and Flexible Duct including a Flow Meter

Related Applications

[001] This application claims priority from Australian provisional patent application no. 2018902052 filed on 7 June 2018, the contents of which are incorporated by reference.

Technical Field

[002] The invention relates to a flow meter. More specifically, the invention relates to a flow meter in the form an annubar for a flexible duct and a flexible duct including such an annubar.

Background

[003] Flexible ducting is used in various applications, such as in underground mining and tunnelling, to provide ventilation. Such flexible ducting may be formed from various materials such as polyethylene woven coated fabric or polyester coated PVC (Polyvinyl Chloride).

[004] In underground environments, the flexible ducting is often placed along a wall or a roof of a tunnel or roadway with an air discharge toward a tunnel end and a return air flow passing contra to the flexible ducting. Due to its location in a working environment, flexible ducting is often impacted upon such as during installation or when a vehicle or other equipment nudges past the flexible ducting. As such, any parts or equipment fitted to the flexible ducting may become damaged.

[005] Accordingly, in an attempt to measure flow from a flexible duct, flow sensors are placed in the tunnel or roadway outside of the duct to measure the return air flow. The sensors are not typically placed within the flexible duct due to potential damage when impacted upon and subsequent need for maintenance or replacement that may require the ventilation system to be stopped. [006] The invention disclosed herein seeks to overcome one or more of the above identified problems or at least provide a useful alternative.

Summary

[007] In accordance with a first broad aspect there is provided, a flow meter for a flexible duct, the flow meter including a pressure sensor and a substantially flexible elongate body arranged to be supported between opposing sides of the flexible duct, the elongate body including an upstream hollow tube and a downstream hollow tube each adapted to respectively communicate air at the upstream and downstream side of the elongate body with the pressure sensor.

[008] In an aspect, the upstream hollow tube includes a plurality of first apertures arranged to face air flow within the flexible duct, and wherein the downstream tube includes a plurality of second apertures arranged to face in an opposing direction away from the air flow.

[009] In another aspect, at least one of the number and size of the plurality of first and second apertures are equal.

[0010] In yet another aspect, the upstream and downstream hollow tubes substantially span an internal diameter of the flexible duct.

[0011] In yet another aspect, the upstream and downstream hollow tubes are parallel to one another.

[0012] In yet another aspect, the upstream and downstream hollow tubes are coupled to one another to form the elongate body.

[0013] In yet another aspect, the upstream and downstream hollow tubes each include coupling portions at opposing ends thereof arranged to couple with pockets of the flexible duct. [0014] In yet another aspect, the coupling portions are provided in the form of perpendicular tube sections coupled to the upstream and downstream hollow tubes via respective elbows, the perpendicular tube sections being received by the pockets.

[0015] In yet another aspect, the upstream and downstream hollow tubes are each substantially formed of plastic.

[0016] In yet another aspect, opposing ends of the elongate body are adapted to couple with opposing sides of the flexible duct.

[0017] In yet another aspect, the upstream and downstream hollow tubes are communicated with the sensor using flexible conduits.

[0018] In yet another aspect, the flow meter is coupled to an internal surface of the flexible duct with the flexible conduits extending between the sensor and the upstream and downstream hollow tubes.

[0019] In yet another aspect, the upstream and downstream hollow tubes horizontally span the flexible duct and the flow sensor is located above the upstream and downstream hollow tubes at least one of toward or at a top side of the flexible duct.

[0020] In yet another aspect, the upstream and downstream hollow tubes are formed from plastic pipes.

[0021] In accordance with a second broad aspect there is provided, a flexible duct adapted to support a flow meter as defined above and herein.

[0022] In accordance with a third broad aspect there is provided, a flexible duct including a flow meter, the flow meter including a pressure sensor and a substantially flexible elongate body arranged to be supported between opposing sides of the flexible duct, the elongate body including an upstream hollow tube and a downstream hollow tube each adapted to respectively communicate air at the upstream and downstream side of the elongate body with the pressure sensor.

[0023] In an aspect, the opposing sides of the flexible duct include pockets adapted to receive coupling portions at opposing ends of the elongate body so as to retain the elongate body and upstream and downstream hollow tubes thereof substantially horizontally across the flexible duct.

[0024] In accordance with a fourth broad aspect there is provided, a method for forming a flow meter for a flexible duct, the method including the steps of: joining in parallel upstream and downstream flexible hollow tubes with respective apertures through side walls thereof facing away from one another; forming coupling portions at opposing ends of the flexible hollow tubes so as to be coupled in a fitted condition with opposing sides of the flexible duct; communicating upstream and downstream flexible conduits between a centre of each of the parallel upstream and downstream flexible hollow tubes and a pressure sensor such that in the fitted condition the pressure sensor is locatable relatively above the upstream and downstream flexible hollow tubes.

Brief Description of the Figures

[0025] The invention is described, by way of non-limiting example only, by reference to the accompanying figures, in which;

[0026] Figure l is a sectional view illustrating a flow meter fitted within a flexible duct; and

[0027] Figure 2 is a perceptive view illustrating the flow meter fitted within the flexible duct.

Detailed Description

[0028] Referring to Figures 1 and 2, there is shown a flexible duct arrangement 10 including a flow meter 12 and a flexible duct 14. The flexible duct 14 may be a main duct or a branch duct that is part of a ventilation system for a mine, a tunnel, a building or the like. The flexible duct 12 may be formed of, but not limited, to polyethylene woven coated fabric or polyester coated PVC (Polyvinyl Chloride).

[0029] The flow meter 12 includes a pressure sensor 16, a substantially flexible elongate body 18 arranged to be supported between opposing sides 21 of the flexible duct 14 and flexible conduits 20 extending between the elongate body 18 and the pressure sensor 16. The elongate body 18 includes an upstream hollow tube 22 and a downstream hollow tube 24 each adapted to respectively communicate air at the upstream and downstream sides 26a, 26b of the elongate body 18 with the pressure sensor 16 via the flexible conduits 20.

[0030] The upstream hollow tube 22 includes a plurality of spaced apart first apertures 28 arranged to face air flow within the flexible duct 14, and the downstream hollow tube 24 includes a plurality of spaced apart second apertures 30 arranged to face in an opposing direction away from the air flow. The first and second apertures 28, 30 are provided in the same number, at similar sizes and at similar spaced apart intervals across the upstream hollow tube 22 and downstream hollow tube 24. The aperture dimensions may preferably be aligned and formed to ISO standards.

[0031] The upstream hollow tube 22 thereby measuring the“high pressure” side and the downstream hollow tube 24 measuring the“low pressure side”. The spacing of the first apertures 28 allows internal averaging of the pressure within the upstream hollow tube 22 and thereby providing an average measurement across the flexible duct 14. It is noted that in some examples the second apertures 30 may comprise only a single aperture so as to provide a single static pressure port.

[0032] Each of the upstream and downstream hollow tubes 22, 24 includes an intermediate aperture 32 provide at a T-junction 34 that is communicated with each of the flexible conduits 20. The pressure sensor 16 being preferably provided as a differential pressure sensor such that the flow meter 12 functions as an annubar. The difference between the total pressure at the upstream side and the static pressure is effectively a measure of the fluid velocity head, which together with the cross-sectional area of the flexible duct 14 allows the volumetric flowrate to be determined.

[0033] The upstream and downstream hollow tubes 22, 24 substantially span an internal diameter of the flexible duct 14 and are arranged horizontally across the flexible duct 14 so as to pass through the centre thereof. The upstream and downstream hollow tubes 22, 24 are parallel to one another and connected by a coupling part 38 to form the elongate body 18. [0034] The upstream and downstream hollow tubes 22, 24 each include coupling portions 42, 44 at opposing ends 46, 48 thereof arranged to couple with duct couplings 50 at the opposing sides 21 the flexible duct 14. In this example, the coupling portions 42, 44 are provided in the form of perpendicular tube sections 56, 58 coupled to the upstream and downstream hollow tubes 22, 24 via respective elbows 60, 62. The perpendicular tube sections 56, 58 are blinded. The duct couplings 50 are provided in the form of pockets 64, 66 at the opposing sides 21 the flexible duct 14. The perpendicular tube sections 55, 58 are removeably receivable by the pockets 64, 66 to support the elongate body 18 across the flexible duct 14. Of course, other means for coupling may be employed such as fasteners, guides or eyelets. The pockets 64, 66 may be sewn or otherwise affixed to the opposing sides 21 of the flexible duct 14.

[0035] The pressure sensor 16 is typically mounted to an inside top 70 of the flexible duct 14 with the flexible conduits 20 extending downwardly to the T-junction 34. The position of the pressure sensor 16 placing it away from potential impact on the sides 21 or bottom of the flexible duct 14. The pressure sensor 16 may be a wired or wireless differential pressure gauge. In the case of the wired arrangement, of course, a wire may be passed through an aperture (not shown) out from the flexible duct 14. It is noted that the flexible conduits 20 allow the pressure sensor 16 and elongate body 18 to move relative to one another.

[0036] The upstream and downstream hollow tubes 22, 24 may be provided in the form of hollow plastic tube such as commonly available PVC (Polyvinyl Chloride) piping or the like. The T-junction 34, elbows 60, 62 and perpendicular tube sections 56, 58 may also be provided in the form of plastic commonly available parts such that the elongate body 18 can be relatively simply and cheaply constructed. Importantly, the plastic construction provides the elongate body 18 with flexibility so that, for example, if the bottom of the flexible duct 14 is impacted and this encroaches on the elongate body 18, the elongate body 18 is able to bend and flex to absorb the impact without damage. The plastic of the elongate body 18 is also resilient so it returns to its original shape. Moreover, the flexible conduits 20 allow the elongate body 18 to move, such as moving upwardly, relative to the sensor 16 thereby assisting to protect the sensor 16. [0037] Accordingly, the elongate body 18 may be simply formed with a set of PVC tubes and connectors arranged to provide the upstream and downstream hollow tubes 22, 24. The pipes may be fitted together with glue using the T-junction 34, elbows 60, 62 and perpendicular tube sections 55, 58. The apertures 28, 30 may be drilled as required and the couplings 38 may be small plates glued or otherwise affixed to hold the upstream and downstream hollow tubes 22, 24 together. In this example, the upstream and downstream hollow tubes 22, 24 may have a diameter in the range of about lOmm to 50mm. However, other sizes may be used.

[0038] The flexible duct 14 may be manufactured with the pockets 64, 66 or the pockets 64, 66 or may be retro-fitted. The pockets 64, 66 allow the perpendicular tube sections 55, 58 to be slid into and out of the pockets 64, 66. The flow meter 12 may need to be calibrated at first use. However, may then be used, in effect, as an annubar to measure the volumetric flowrate through the flexible duct 14.

[0039] Advantageously, there has been described a flexible duct arrangement including a flow meter especially suitable for a flexible duct. In particular, the elongate body of the flow meter is flexible to allow for bending and is moveable relative to the pressure sensor so as to avoid damage when the flexible duct is moved such as being impacted upon. Further, the elongate body is formable from simple PVC pipes and connectors to allow for inexpensive manufacture, ease of maintenance, has excellent chemical resistance and also robust construction.

[0040] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0041] The reference in this specification to any known matter or any prior publication is not, and should not be taken to be, an acknowledgment or admission or suggestion that the known matter or prior art publication forms part of the common general knowledge in the field to which this specification relates. [0042] While specific examples of the invention have been described, it will be understood that the invention extends to alternative combinations of the features disclosed or evident from the disclosure provided herein.

[0043] Many and various modifications will be apparent to those skilled in the art without departing from the scope of the invention disclosed or evident from the disclosure provided herein.

Claims

The claims defining the Invention are as follows:

1. A flow meter for a flexible duct, the flow meter including a pressure sensor and a substantially flexible elongate body arranged to be supported between opposing sides of the flexible duct, the elongate body including an upstream hollow tube and a downstream hollow tube each adapted to respectively communicate air at the upstream and downstream side of the elongate body with the pressure sensor.

2. The flow meter according to claim 1 , wherein the upstream hollow tube includes a plurality of first apertures arranged to face air flow within the flexible duct, and wherein the downstream tube includes a plurality of second apertures arranged to face in an opposing direction away from the air flow.

3. The flow meter according to claim 2, wherein at least one of the number and size of the plurality of first and second apertures are equal.

4. The flow meter according to claim 2, wherein the upstream and downstream hollow tubes substantially span an internal diameter of the flexible duct.

5. The flow meter according to claim 2, wherein the upstream and downstream hollow tubes are parallel to one another.

6. The flow meter according to claim 2, wherein the upstream and downstream hollow tubes are coupled to one another to form the elongate body.

7. The flow meter according to claim 2, wherein the upstream and downstream hollow tubes each include coupling portions at opposing ends thereof arranged to couple with pockets of the flexible duct.

8. The flow meter according to claim 7, wherein the coupling portions are provided in the form of perpendicular tube sections coupled to the upstream and downstream hollow tubes via respective elbows, the perpendicular tube sections being received by the pockets.

9. The flow meter according to claim 2, wherein the upstream and downstream hollow tubes are each substantially formed of plastic.

10. The flow meter according to claim 1, wherein opposing ends of the body are adapted to couple with opposing sides of the flexible duct.

11. The flow meter according to any one of the previous claims, wherein the upstream and downstream hollow tubes are communicated with the sensor using flexible conduits.

12. The flow meter according to claim 11, wherein the flow meter is coupled to an internal surface of the flexible duct with the flexible conduits extending between the sensor and the upstream and downstream hollow tubes.

13. The flow meter according to any one of the previous claims, wherein the upstream and downstream hollow tubes horizontally span the flexible duct and the flow sensor is located above the upstream and downstream hollow tubes at least one of toward or at a top side of the flexible duct.

14. The flow meter according to any one of the previous claims, wherein the upstream and downstream hollow tubes are formed from plastic pipes.

15. A flexible duct adapted to support a flow meter as defined in any one of the previous claims.

16. A flexible duct including a flow meter, the flow meter including a pressure sensor and a substantially flexible elongate body arranged to be supported between opposing sides of the flexible duct, the elongate body including an upstream hollow tube and a downstream hollow tube each adapted to respectively communicate air at the upstream and downstream side of the elongate body with the pressure sensor.

17. The flexible duct according to claim 16, wherein the opposing sides of the flexible duct include pockets adapted to receive coupling portions at opposing ends of the elongate body so as to retain the elongate body and upstream and downstream hollow tubes thereof substantially horizontally across the flexible duct.

18. A method for forming a flow meter for a flexible duct, the method including the steps of: Joining in parallel upstream and downstream flexible hollow tubes with respective apertures through side walls thereof facing away from one another; Forming coupling portions at opposing ends of the flexible hollow tubes so as to be coupled in a fitted condition with opposing sides of the flexible duct; Communicating upstream and downstream flexible conduits between a centre of each of the parallel upstream and downstream flexible hollow tubes and a pressure sensor such that in the fitted condition the pressure sensor is locatable relatively above the upstream and downstream flexible hollow tubes.