WO1994010398A1

WO1994010398A1 - Stormwater discharge regulator

Info

Publication number: WO1994010398A1
Application number: PCT/AU1993/000574
Authority: WO
Inventors: Peter John Higgins
Original assignee: Peter John Higgins
Priority date: 1992-11-04
Filing date: 1993-11-04
Publication date: 1994-05-11
Also published as: AU5412794A

Abstract

A discharge flow regulator (11) for a tank (10) or the like comprises a chamber (13) having a regulator inlet (14), a regulator outlet (15) and a flow arrester (16) associated therewith. The regulator inlet (14) is adapted for liquid communication with the storage tank outlet (12). Rate of liquid outflow from chamber (13) is limited by design of regulator outlet (15) to the predetermined flow rate which is a function of the permitted maximun head of liquid in the chamber (13). In turn the permitted maximum head of liquid in the chamber (13) is regulated by flow arrestor (16) whereby the liquid flow rate from the storage tank (10) or the like is limited to the predetermined flow rate and is substantially independent of the pressure of liquid within the storage tank outlet/regulator inlet.

Description

_STORMWATER DISCHARGE REGULATOR

TECHNICAL FIELD

The present invention relates to a discharge flow regulator and, more particularly, to a discharge flow regulator adapted to regulate the outflow of liquid from a variable head storage volume. BACKGROUND ART

In recent years, particularly due to increased population density in many urban areas, there has arisen a need to regulate runoff of rainwater and the like from individual properties to a maximum predetermined rate independent of the rate of rainfall and water flow onto the property.

For example, a problem occurs during periods of heavy rainfall when, if left unchecked, the rate of flow of rainwater away from individual land holdings is very high such that the cumulative effect of flow away from all properties within a given area causes flooding or in a combined sewer and stormwater system causes sewer overflows.

Accordingly, some local authorities have introduced regulations requiring that rainwater and the like falling on any given property be directed to an on site detention means, and wherein the maximum rate of outflow from the detention means must not exceed a predetermined amount.

It is an object of the present invention to provide a mechanism and method for regulating the outflow of water from the detention volume to a maximum predetermined flow

SUBSTITUTE SHEET rate .

A subsidiary problem concerns the sensitivity of the discharge flow regulator to inlet head.

It is an object of at least preferred embodiments of the invention to provide a discharge flow regulator whose outlet characteristics are relatively insensitive to inlet head pressure. DISCLOSURE OF INVENTION

Accordingly, in one broad form of the invention there is provided a discharge flow regulator for limiting liquid flow rate from an outlet 'of a liquid storage means to a predetermined flow rate, said discharge flow regulator comprising a chamber having a regulator inlet, a regulator outlet and a flow arrester associated therewith; said regulator inlet being adapted for liquid communication with said storage means outlet; said regulator outlet being adapted to limit maximum liquid flow rate from said chamber through said regulator outlet to said predetermined flow rate as determined by the permitted maximum head of liquid within said chamber; said flow arrester being adapted to regulate flow of liquid through said regulator inlet into said chamber such that said permitted maximum head of liquid in said chamber is not exceeded whereby, as a consequence, the liquid flow rate from said storage means outlet is limited to said predetermined flow rate and is substantially independent of the pressure of liquid withir. said storage means outlet.

Preferably the flow arrester comprises a valve actuated

SUBSTITUTE SHEET by chamber liquid level sensing means whereby said valve prevents further inflow of liquid in said chamber when said level sensing means detects a liquid level in said chamber corresponding to said permitted maximum head of liquid within said chamber.

Preferably, said level sensing means comprises a float.

The float may include valve means adapted to seat within a valve seat on said regulator inlet whereby said valve and valve seat regulate inflow of liquid to said chamber through said regulator inlet as said float rises with liquid level in said' chamber to a height corresponding to said permitted maximum head.

The float may further include guide means to ensure alignment of said valve with said valve seat as said float moves with the liquid level within said chamber.

The guide means may act with reference to the sidewalls of said chamber, an external surface of said regulator inlet, or to an inside surface of said regulator inlet.

Preferably, said guide means comprises guide rods rising from a base surface of said chamber and passing into corresponding apertures within said float.

In a particular preferred form of the invention the float is hinged whereby said valve approaches said valve seat along an arc. The flow arrester may be combined integrally with said regulator inlet whereby a pinch point located along said regulator inlet is progressively pinched so as to regulate flow of liquid within said regulator inlet as a float

SUBSTITUTE SHEET attached to said inlet rises with the liquid level within said chamber and moving at least a portion of said regulator inlet in an arc whereby said pinch point becomes closed when said liquid level corresponds to said permitted maximum head within said chamber.

In yet a further broad form of the invention there is provided a method of regulating discharge flow from a storage means comprising regulating the head of liquid in a chamber which is in fluid communication with an outlet of said storage means.

In yet a further broad form of the invention there is provided a dosing system which provides a selectable liquid flow rate from an outlet of a liquid storage means said system comprising said liquid storage means and a discharge flow regulator comprising a chamber having a regulator inlet, a regulator outlet and a flow arrester associated therewith; said regulator inlet being adapted for liquid communication with said storage means outlet; said regulator outlet being adapted to limit maximum liquid flow rate from said chamber through said regulator outlet to said predetermined flow rate, said flow arrester being adapted to regulate flow of liquid through said regulator inlet into said chamber such that a permitted maximum head of liquid in said chamber is not exceeded. BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention will now be described with reference to the accompanying drawings wherein:-

SUBSTITUTE SHEET Fig. 1 is a side section view of an on site detention storage tank connected to a discharge flow regulator according to a first embodiment of the invention, Fig. 2 is an enlarged view of the valve of the discharge flow regulator shown in Fig. 1, Fig. 3 is a side section view of a discharge flow regulator according to a second embodiment of the invention, Fig. 4 is a side section view of a discharge flow regulator according to a third embodiment of the invention, Fig. 5 is a side section view of a discharge flow regulator according to a fourth embodiment of the invention,

Fig. 6 is a side section view of a discharge flow regulator according to a fifth embodiment of the invention, and Fig. 7 is a side section view of a modified storage tank outlet,

Fig. 8 is a side section view of a modified valve seat, Fig. 9 is a side section view of a further modification of the valve seat of Fig. 8, Fig. 10 is a side section view of a further modification of the valve of Fig. 8, Fig. 11 is a side section view of a low profile arrangement for an inlet to the discharge

SUBSTITUTE SHEET flow regulator and, Fig. 12 is a modification of the arrangement of

Fig . 1 adapted for use as dosing apparatus or the like. MODES FOR CARRYING OUT THE INVENTION

Fig. 1 illustrates, in side section, an on site detention storage means 10, which in this instance is a tank in fluid communication with a discharge flow regulator 11 according to a first embodiment of the invention. A description of this arrangement together with some of the underlying theory upon which the design is based is disclosed in Australian Provisional Patent Application No. PL 5654 in the name of the present applicant. The entire text and drawings of the specification of that application is incorporated herein by cross reference.

The storage tank 10 is in liquid communication with chamber 13 via storage tank outlet 12 and regulator iniet 14. Liquid within chamber 13 can flow through regulator outlet 15 to an exit location such as a council stormwater drain or the like.

The discharge flow regulator 11 includes a flow arrester 16 which comprises three components, namely a float 17, a valve 18 and a guide 19. The valve 18 (which is shown in greater detail in Fig. 2) includes a valve projection 20 attached to a top surface of float 17 and a valve seat 21 comprising an open end of regulator inlet 14. When float 17 rises with the liquid level in chamber 13 to a point where valve projection 20 seats firmly within valve

SUBSTITUTE SHEET seat 21, inflow of liquid from storage tank outlet 12 to chamber 13 via regulator inlet 14 is prevented by valve 18. Guide 19 ensures that lateral movement of float 17 is restricted to ensure that valve projection 20 will always seat within valve seat 21.

Regulator outlet 15 includes a liquid flow restricting orifice 22 sized to permit a maximum predetermined flow of liquid through regulator outlet 15 as calculated with reference to the maximum height (or head) of liquid permitted within chamber 13. This maximum height of liquid is determined by the height which float 13 reaches which corresponds to shut-off of further flow of liquid from storage tank outlet 12 by the action of valve 18.

Clearly, the pressure of liquid at storage tank outlet 12 is determined by the head of liquid within tank 10.

Accordingly the closing pressure of valve 18 will need to be correspondingly higher as the head of liquid within tank 10 rises. The increased closing pressure is provided by a slight increase in height of liquid level within chamber 13 around float 17 (Archimedes' principle).

Tank 10 includes a coarse screen 23 to keep solids above a predetermined size away from storage tank outlet 12. Storage tank outlet 12 will typically be placed close to, but not at, the bottom of tank lυ thereby leaving a sump space 24 at the bottom of tank 10.

In use liquid within tank 10 flows via storage tank outlet 12 through regulator inlet 14 into chamber 13 and out through regulator outlet 15 under the influence of

T SHEET gravi ty .

The various components of the system are sized so that, under most head conditions within tank 10 the rate of liquid flow into chamber 13 has the potential to be greater than the allowed outflow from chamber 13 through orifice 22. Accordingly, the liquid level within chamber 13 will rise and float 17 will rise with that liquid level to a point where valve projection 20 is urged into valve seat 21 with sufficient force that further liquid flow through regulator inlet 14 is prevented. Liquid within chamber 13 continues to flow through orifice 22 and out through regulator outlet 15 such that the level of liquid in chamber 13 will drop, float 17 will drop with that liquid level and valve 18 will be opened at least partially to allow further liquid flow into chamber 13.

This procedure of float rise and float fall continues whilst there is a head of liquid within tank 10 sufficient to cause the flow rate of liquid into chamber 13 to be greater than the allowed flow rate out of chamber 13. In this manner the liquid flow rate out of the combined system of the storage tank 10 and the discharge flow regulator 11 is limited to a predetermined value.

It will be noted that a characteristic of the system is that the flow rate through orifice 22 is determined primarily with reference to the dimensions of the orifice and the maximum head of liquid within chamber 13. The head of liquid within tank 10 does not have a primary influence over the flow rate of liquid through orifice 22. That is,

SUBSTITUTE SHEET this arrangement allows for a substantial decoupling of the liquid head in chamber 13 from the liquid head in the storage tank 10 by the action of flow arrester 16. Accordingly, the dimensions of the storage tank, and particularly, its height, can be selected without regard to outlet flow considerations as these are determined effectively entirely by the discharge flow regulator 11 and, particularly, the maximum permitted head of liquid within chamber 13 of regulator 11 relative to orifice 22 in regulator outlet 15.

Fig. 3 illustrates a second embodiment of the discharge flow regulator wherein a float 25 operates a valve 18 generally in the manner described with reference to the first embodiment. In this case the float 25 is in the form of a ring as illustrated and utilises a portion of regulator inlet 14 as a guide to ensure seating of valve projection 20 on valve seat 21.

Fig. 4 illustrates a third embodiment of the discharge flow regulator wherein a float 26 is located near a far end of a hinged lever arm 27 hinged at pivot point 28. Valve projection 20 is located between pivot point 28 and float 26 and moves in an arc from a flow permitting position to a flow sealing position when it is seated in valve seat 21 as illustrated. Fig. 5 illustrates a fourth embodiment of the regulator wherein a float 29 is in the form of a sliding stopper which includes raised sides 30 adapted to sealingly cover a slot 31 in regulator inlet 14. In a flow permitting

IT TE SHEET condition liquid flows through regulator inlet 14 and out through slot 31 into chamber 13. As the liquid level rises in chamber 13 to its permitted maximum head float 29 rises so that raised sides 30 seal slot 31. Fig. 6 illustrates a fifth embodiment of the invention wherein a float 32 is attached to an end portion of a plastically deformable pipe 33 including a pinch point 34. The pipe 33 comprises the regulator inlet 14 combined with flow arrester 16. Its operation is such that as the liquid level in chamber 13 rises to the permitted maximum head float 32 moves that portion of pipe 33 between pinch point 34 and float 32 in an arc about pinch point 34, finally reaching a position corresponding to permitted maximum head of liquid within the chamber 13 where pinch point 34 is deformed to the extent where it prevents further flow of liquid within inlet 14 into chamber 13.

Figs. 7 to 9 illustrates modifications to the first embodiment of the invention as illustrated in Fig. 1. Fig. 7 shows a modification to storage tank outlet 12 comprising an oil trap 35 located within sump 24. The oil trap 35 comprises a downwardly turned extension 36 arranged such that there is always at least a height H of liquid in storage tank 10 above the outlet orifice 37. With this arrangement, oil and the like which tends to remain on the surface of the liquid within tank 10 will remain above the level of outlet orifice 37 and thereby remain within sump 24 for subsequent pump out as an independent operation. Breather tube 44 serves to break the siphon that might

SUBSTITUTE SHEET otherwise be induced in extension 36.

Figs. 8 and 9 illustrates two alternative arrangements for valve seat 21 with respect to valve projection 20. Fig. 8 illustrates a valve seat 21 which operates in essentially the same way as the valve seat illustrated and described with respect to Fig. 1. In this modification, the slope of the conical surface 38 of valve seat 21 is less steep than the corresponding conical surface 39 of projection 20 so that seating of the two surfaces 38, 39 takes place only along a narrowly defined seating line 40. Whilst the operation of the valve 18 illustrated in Fig. 8 is the same as previously described in respect of Fig. 1 it has been found that, in practice, with this arrangement there is likelihood of valve chatter. Fig. 9 illustrates the valve 18 of Fig. 8 with channels

41 cut into the surface of the valve projection 20. The channels 41 serve to allow a predetermined minimum flow of liquid through valve 18 even when valve seat 21 is at its point of closest approach to valve projection 20. The arrangement of Fig. 9 can be thought of as a "leaky" valve which permits a minimum liquid flow rate therethrough. The minimum flow rate therethrough is selected, by appropriate design of channel 41, to be less than the design flow rate of liquid out of chamber 13 via regulator outlet 15. Operation of the valve of Fig. 9 is much the same as in respect of the first embodiment save that there is no absolute turn off of liquid flow from storage tank 10 via valve 18 but only, at maximum regulation, a reduction in

SUBSTITUTE SHEET flow into chamber 13 to less than the rate of outflow from chamber 13 whereby the level of liquid within chamber 13 will reduce.

With reference to Fig. 10, an alternative embodiment of the "leaky valve" concept utilises relief ducts 42 or 43 to provide a liquid connection between the storage means and the chamber independent of the relative position of the valve seat 21 with respect to the valve projection 20.

With reference to Fig. 11 there is shown an alternative inlet arrangement to chamber 13 which allows the regulator assembly to have a relatively low height dimension.

The arrangement comprises bringing regulator inlet 14 into chamber 13 through a side 50 thereof such that inlet 14 is entirely below the liquid level sensitive component, which in this case comprises float 51. Valve 18 is actuable by float 51 by means of extension legs 52, 53 whereby valve projection 54 becomes seated against valve seat 55 as it is urged upwardly by float 51 acting through legs 52, 53 when liquid level 56 reaches a predetermined height within chamber 13.

Fig. 12 illustrates an alternative utilisation of the assembly of Fig. 1 which takes advantage of the liquid head pressure limiting capabilities of the flow arrestor assembly 16 operating within chamber 13. In this arrangement tank 10 comprises a store of liquid for dosing liquid contained in tank 60. Outlet 15 includes a mechanism for providing a predetermined rate of flow through regulator outlet 15 and into tank 60. In this case

SUBSTITUTE SHEET the mechanism comprises gate 61 of a gate valve (not shown) adapted for control by a control mechanism (not shown) whereby a predetermined dose rate of liquid from tank 10 is provided through outlet 15 by control of aperture area 62 via gate 61. The sensitivity of flow rate through outlet

15 through aperture 62 to the head in tank 10 is removed by the isolating action of the assembly in chamber 13 which causes the head pressure to which outlet 15 is exposed to be determined by the assembly within tank 13 independent of the head pressure in tank 10.

The flow control assembly within inlet 15 can be replaced by other flow control assemblies such as, for example, a diaphragm pump. Many positive displacement pump arrangements, which ostensibly are insensitive to incoming head pressure, can benefit from their utilisation in conjunction with the head isolation arrangements described in the various embodiments in this specification.

The above describes only some embodiments of the present invention and modifications obvious to those skilled in the art can be made thereto without departing from the scope and spirit of the present invention.

SUBSTITUTE SHEET

Claims

1. A discharge flow regulator for limiting liquid flow rate from an outlet of a liquid storage means to a predetermined flow rate, said discharge flow regulator comprising a chamber having a regulator inlet, a regulator outlet and a flow arrester associated therewith; said regulator inlet being adapted for liquid communication with said storage means outlet; said regulator outlet being adapted to limit maximum liquid flow rate from said chamber through said regulator outlet to said predetermined flow rate as determined by th≤ permitted maximum head of liquid within said chamber; said flow arrester being adapted to regulate flow of liquid through said regulator inlet into said chamber such that said permitted maximum head of liquid in said chamber is not exceeded whereby, as a consequence, the liquid flow rate from said storage means outlet is limited to said predetermined flow rate and is substantially independent of the pressure of liquid within said storage volume outlet.

2. The discharge flow regulator of claim 1 wherein said flow arrester comprises a valve actuated by chamber liquid level sensing means whereby said valve prevents further inflow of liquid in said chamber when said level sensing means detects a liquid level in said chamber corresponding to said permitted maximum head of liquid within said chamber.

3. The regulator of claim 2 wherein said level sensing means comprises a float.

SUBSTITUTE SHEET

4. The regulator of claim 3 wherein said float includes valve means adapted to seat within a valve seat on said regulator inlet whereby said valve and valve seat prevent inflow of liquid to said chamber through said regulator inlet as said float rises with liquid level in said chamber to a height corresponding to said permitted maximum head.

5. The regulator of claim 4 wherein said float includes guide means to ensure alignment of said valve with said valve seat as said float moves with the liquid level within said chamber.

6. The regulator of claim 5 wherein said guide means acts with respect to the sidewalls of said chamber.

7. The regulator of claim 5 wherein said guide means acts with respect to an external surface of said regulator inlet.

8. The regulator of claim 3 wherein said float is hinged whereby said valve approaches said valve seat along an arc.

9. The regulator of claim 1 or claim 2 wherein said flow arrester is combined integrally with said regulator inlet whereby a pinch point located along said regulator inlet is progressively pinched so as to regulate flow of liquid within said regulator inlet as a float attached to said inlet rises with the liquid level within said chamber.

10. The regulator of any preceding claim wherein said regulator outlet includes an orifice therein adapted to limit maximum liquid flow rate from said chamber therethrough to said predetermined flow rate as determined by the permitted maximum head of liquid within said

SUBSTITUTE SHEET chamber .

11. A dosing system which provides a selectable liquid flow rate from an outlet of a liquid storage means, said system comprising said liquid storage means and a discharge flow regulator comprising a chamber having a regulator inlet, a regulator outlet and a flow arrester associated therewith; said regulator inlet being adapted for liquid communication with said storage means outlet; said regulator outlet being adapted to limit maximum liquid flow rate from said chamber through said regulator outlet to said predetermined flow rate, said flow arrester being adapted to regulate flow of liquid through said regulator inlet into said chamber such that a permitted maximum head of liquid in said chamber is not exceeded.

12. A method of regulating discharge flow from a storage means comprising regulating the head of liquid in a chamber which is in fluid communication with an outlet of said storage means.

13. The method of claim 12 wherein said method further includes providing regulation of outflow from said chamber by means of an orifice.

14. The method of claim 13 wherein said head of liquid in said chamber is regulated by a shut-off mechanism which is sensitive to and is actuated by said head of liquid reaching a predetermined value within said chamber.

SUBSTITUTE SHEET AMENDED CLAIMS

[received by the International Bureau on 21 April 1994 (21.04.94); new claims 15-21 added;other claims unchanged (3 pages)]

15. A discharge flow regulator for limiting liquid flow rate from an outlet of a liquid storage means to a predetermined flow rate, said discharge flow regulator comprising a chamber having a regulator inlet, a regulator outlet and a flow arrester associated therewith; said regulator inlet being adapted for liquid communication with said storage means outlet; said regulator outlet being adapted to limit maximum liquid flow rate from said chamber through said regulator outlet to said predetermined flow rate as determined by the permitted maximum head of liquid within said chamber; said_' flow arrester being adapted to regulate flow of liquid through said regulator inlet into said chamber such that said permitted maximum head of liquid In said chamber is not exceeded whereby, as a consequence, the liquid flow rate from said storage means outlet is limited to said predetermined flow rate and is substantially independent of the pressure of liquid within said storage volume outlet; and wherein said flow arrestor comprises a valve actuated by chamber liquid level sensing means whereby said valve prevents further inflow of liquid in said chamber when said level sensing means detects a liquid level inside the chamber corresponding to said permitted maximum head of liquid in said chamber; said discharge flow regulator further including valve anti- chatter means.

16. The regulator of claim 15 wherein said level sensing means comprises a float and wherein said float includes valve means adapted to seat within a valve seat on said regulator inlet whereby said valve and said valve seat prevent inflow of liquid to said chamber through said regulator inlet as said float rises with liquid level in said chamber to a height corresponding to said permitted maximum head; and wherein said valve anti-chatter means arranging the slope of the conical surface of the valve seat to be less steep than the corresponding conical surface of a projection upon which said valve is to seat.

17. The regulator of claim 15 wherein said level sensing means comprises a float and wherein said float includes valve means adapted to seat within a valve seat on said regulator inlet whereby said valve and said valve seat prevent inflow of liquid to said chamber through said regulator inlet as said float rises with liquid level in said chamber to a height corresponding to said permitted maximum head; said valve anti-chatter means comprising a permanent orifice passing through said valve seat or parallel to it so that said valve can never arrest totally liquid flow therethrough; and wherein the minimum flow rate therethrough is selected to be less than the design flow rate of liquid out of said regulator outlet.

18. The regulator of claim 15 wherein said level sensing means comprises a float and wherein said float includes valve means adapted to seat within a valve seat on said regulator inlet whereby said valve and said valve seat prevent inflow of liquid to said chamber through said regulator inlet as said float rises with liquid level in said chamber to a height corresponding to said permitted maximum head; said valve anti-chatter means comprising arranging said valve such that the rate of closure of said valve is relatively slow relative to change in the head of liquid in said chamber.

19. A discharge flow regulator for limiting liquid flow rate from an outlet of a liquid storage means to a predetermined flow rate, said discharge flow regulator comprising a chamber having a regulator Inlet, a regulator outlet and a flow arrester associated therewith; said regulator inlet being adapted for liquid communication with said storage means outlet; said regulator outlet being adapted to limit maximum liquid flow rate from said chamber through said regulator outlet to said predetermined flow rate as determined by the permitted maximum head of liquid within said chamber; said flow arrester being adapted to regulate flow of liquid through said regulator inlet into said chamber such that said permitted maximum head of liquid in said chamber is not exceeded whereby, as a consequence, the liquid flow rate from said storage means outlet is limited to said predetermined flow rate and is substantially independent of the pressure of liquid within said storage volume outlet; said discharge flow regulator including only one moving part.

20. The regulator of claim 19 wherein said one moving part is included in said flow arrestor.

21. The regulator of claim 20 wherein said moving part comprises a float forming part of a valve.