WO1997045645A2 - Method of securing a tube to a frame - Google Patents

Method of securing a tube to a frame Download PDF

Info

Publication number
WO1997045645A2
WO1997045645A2 PCT/GB1997/001364 GB9701364W WO9745645A2 WO 1997045645 A2 WO1997045645 A2 WO 1997045645A2 GB 9701364 W GB9701364 W GB 9701364W WO 9745645 A2 WO9745645 A2 WO 9745645A2
Authority
WO
WIPO (PCT)
Prior art keywords
contactor
tube
end frame
frame member
ridges
Prior art date
Application number
PCT/GB1997/001364
Other languages
French (fr)
Other versions
WO1997045645A3 (en
Inventor
Roy Henry Bannister
George Eric Findlay
Original Assignee
Severn Trent Water Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Severn Trent Water Limited filed Critical Severn Trent Water Limited
Priority to AU29063/97A priority Critical patent/AU2906397A/en
Publication of WO1997045645A2 publication Critical patent/WO1997045645A2/en
Publication of WO1997045645A3 publication Critical patent/WO1997045645A3/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B9/00—Connections of rods or tubular parts to flat surfaces at an angle
    • F16B9/05—Connections of rods or tubular parts to flat surfaces at an angle by way of an intermediate member
    • F16B9/056—Connections of rods or tubular parts to flat surfaces at an angle by way of an intermediate member the intermediate member extending through the flat surface; the rod or tubular part extending through the flat surface
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B9/00—Connections of rods or tubular parts to flat surfaces at an angle
    • F16B9/05—Connections of rods or tubular parts to flat surfaces at an angle by way of an intermediate member
    • F16B9/054—Connections of rods or tubular parts to flat surfaces at an angle by way of an intermediate member the intermediate member being threaded

Definitions

  • Rotary biological contactors are widely used for the treatment of waste water in sewage works.
  • Such plant comprises at least one tank, though which waste water to be purified is passed, and one or more rotors which comprise packs of planar contactor elements which are ordinarily arranged as a plurality of discs on a shaft.
  • the rotors are arranged to be rotated partly submerged in the tanks; the discs commonly stand vertically on horizontal shafts. As the discs are rotated, waste water becomes picked up from the tank on the surfaces of the contactor elements and excess water drains back into the tank.
  • the elements provide surfaces for the growth of biomass (i.e.
  • a rotor for a rotary biological contactor comprising a plurality of generally planar contactor elements which are each of a corrugated form presenting spaced elongate ridges which extend at an acute angle to the radial extent of the element and between which channels are formed down which water can drain when the element is raised in use from a waste water tank, ridges on at least one side of the planar element being reduced in height at intervals along their lengths to form flow ports interconnecting adjacent channels.
  • the corrugated structure allows thin and light material to form a stiff element providing a large surface area for the collection of biomass. Whilst the corrugated form itself allows drainage, the provision of flow ports between the channels can greatly improve the rate at which excess water drains from the elements. This provides several advantages. Faster drainage of excess water from the elements reduces loadings on the rotor. It also reduces power requirements for driving the rotor. It can also help to reduce a tendency for an excess of biomass to collect at certain places on the element, a more uniform distribution of biomass permitting better air flows and, again, reducing loadings.
  • the invention provides a generally planar contactor element for use in a rotor of a rotary biological contactor, the element being of a corrugated form presenting spaced elongate ridges which extend at an acute angle to the intended radial extent of the element and between which channels are formed down which water can drain when the element is raised in use from a waste water tank, the ridges on at least one side of the planar element being reduced in height at intervals along their lengths to form flow ports interconnecting adjacent channels.
  • the contactor element may be formed of a suitable plastics material, for example high density polyethylene.
  • the invention provides a method of securing a contactor supporting tube to an end frame of a rotary biological contactor, the method comprising drawing the tube longitudinally and tightly up to the end frame member by means of a screw-threaded fastening member which extends through the end frame member to a fixing at the end of the tube.
  • a suitable screw-threaded member may be a bolt which is introduced through the end frame member into a tapped fixing at the end of the tube.
  • a flat end face of the tube or fixing is drawn tightly against a flat face of the end frame member.
  • the fixing may be in the form of a tapped plug secured in the tube.
  • the invention provides a contactor element for a rotary biological contactor, the element being apertured to enable a supporting rod to extend through it, and the element comprising a skirt forming a collar bounding the aperture to engage the surface of the rod.
  • Figure 1 shows a three-pack rotor for a rotary biological contactor
  • Figure 2 is a view in elevation of a contactor element according to the invention
  • Figure 3 shows a section taken through a portion of the element showing full height corrugations
  • Figure 4 shows a section (on a larger scale than Figure 3) through the element at a flow port
  • Figure 5 is a view in the direction of arrow 'A' in Figure 4;
  • Figure 6 is an axial section through a supporting tube/end frame fixing
  • Figure 7 is a view on Section VII-VII of Figure 2.
  • a rotor ( Figure 1) for a rotary biological contactor comprises three or more packs 10, 12, 14 of contactor discs mounted for rotation together on a shaft 16. Each pack comprises forty-one discs secured between end frames 18, 20.
  • Each disc is made up of ten similar contactor elements (Figure 2), each forming a generally planar sector of the disc.
  • the ten sectors of each disc lie in a common plane (perpendicular to the shaft 16). They are not directly joined to one another, being supported by axially-extending supporting rods 19 ( Figure 6) which extend between the end frames 18, 20 through apertures 22, 24, 26 in the contactor elements.
  • the forty-one discs of the rotor are, therefore, effectively created by ten packs of forty-one contactor elements each, the ten packs being uniformly distributed about the shaft 16.
  • Each contactor element ( Figures 2 and 3) is formed from a suitable plastics sheet material (e.g. high density polyethylene).
  • the element is of a corrugated form presenting straight, parallel, equi-spaced elongate ridges 28 over substantially the whole of its area on both sides.
  • the ridges extend at 45° to a radial centre-line of the element.
  • the edge portion 29 of the element, all around its periphery, is turned up to form a reinforcing lip to increase the rigidity of the element.
  • the ridges are interrupted at intervals along their lengths by portions 30 ( Figures 4 and 5) of reduced height forming flow ports 32, providing communication between adjacent channels 34 which are formed on opposite sides of each ridge.
  • the shaft 16 In use of the rotor, the shaft 16 is arranged horizontally, just above the level of waste water in a tank, with the rotor packs 10,12, 14 partially submerged in the tank. As the rotor is rotated, waste water becomes raised from the tank on the surfaces of the contactor elements, as the elements in turn become lifted from the tank. Excess surface water drains off the elements down the channels 34, but drainage is assisted by the flow ports 32 which provide some intercommunication between the channels. Excess water is as a consequence drained more quickly from the contactor elements than would be the case in the absence of such ports, so reducing loadings on the rotor and generally improving efficiency of operation.
  • Each of the supporting rods 19 is in the form of a tube and is secured at its ends to the end frames 18,20 by a method illustrated by Figure 6.
  • a plug 36 is secured by welding in the end of the tube, the plug presenting a flat end face 38 and having a screw-threaded central bore 40.
  • the end face of the plug lies flat against an opposing inner surface of an associated end frame member 42 and the plugged tube 19 firmly bolted to the member by means of a bolt 44 inserted through the member into the tapped plug. In this manner it is ensured that bending moments are transferred from the tubes 19 to the end frames 18,20 whilst avoiding fretting caused by rotation.
  • each element is formed (at each aperture) as shown by Figure 7.
  • the sheet is shaped to form a short cylindrical skirt 46 forming a collar bounding the aperture and being of a similar inner diameter to the outer diameter of the supporting rod 19, the element being a close sliding fit on the rod.

Abstract

Contactor supporting tubes (19) are secured to an end frame (42) of a rotor by drawing each tube tightly up to an end frame by means of a bolt (44) which extends through the end frame member into a tapped plug (36) in the end of the tube. Where each tube (19) passes through an aperture in the contactor element, a reinforcing skirt (46) bounds the aperture.

Description

METHOD OF SECURING A TUBE TO A FRAME
Rotary biological contactors are widely used for the treatment of waste water in sewage works. Such plant comprises at least one tank, though which waste water to be purified is passed, and one or more rotors which comprise packs of planar contactor elements which are ordinarily arranged as a plurality of discs on a shaft. The rotors are arranged to be rotated partly submerged in the tanks; the discs commonly stand vertically on horizontal shafts. As the discs are rotated, waste water becomes picked up from the tank on the surfaces of the contactor elements and excess water drains back into the tank. The elements provide surfaces for the growth of biomass (i.e. bacterial slime) and the alternate exposure of this to the waste water and the air, as the rotor rotates, provides suitable conditions for micro-organisms to digest organic constituents of the waste water to purify the water. One example of such plant is described in WO-92/01636.
Mechanical failures in the rotors of such plant are not unusual. Reversing loadings imposed upon the rotating packs of contactor elements are substantial, and fatigue failures can occur in metal structures supporting the elements. The elements themselves are commonly of plastics sheet material which can split and tear away from fixings under the imposed loads.
It is an object of the present invention to improve the design of such rotors in order to reduce the incidence of mechanical failure and generally to improve the performance of such plant.
The invention provides, in one of its aspects, a rotor for a rotary biological contactor comprising a plurality of generally planar contactor elements which are each of a corrugated form presenting spaced elongate ridges which extend at an acute angle to the radial extent of the element and between which channels are formed down which water can drain when the element is raised in use from a waste water tank, ridges on at least one side of the planar element being reduced in height at intervals along their lengths to form flow ports interconnecting adjacent channels.
The corrugated structure allows thin and light material to form a stiff element providing a large surface area for the collection of biomass. Whilst the corrugated form itself allows drainage, the provision of flow ports between the channels can greatly improve the rate at which excess water drains from the elements. This provides several advantages. Faster drainage of excess water from the elements reduces loadings on the rotor. It also reduces power requirements for driving the rotor. It can also help to reduce a tendency for an excess of biomass to collect at certain places on the element, a more uniform distribution of biomass permitting better air flows and, again, reducing loadings.
In another of its aspects the invention provides a generally planar contactor element for use in a rotor of a rotary biological contactor, the element being of a corrugated form presenting spaced elongate ridges which extend at an acute angle to the intended radial extent of the element and between which channels are formed down which water can drain when the element is raised in use from a waste water tank, the ridges on at least one side of the planar element being reduced in height at intervals along their lengths to form flow ports interconnecting adjacent channels.
The contactor element may be formed of a suitable plastics material, for example high density polyethylene. In another of its aspects the invention provides a method of securing a contactor supporting tube to an end frame of a rotary biological contactor, the method comprising drawing the tube longitudinally and tightly up to the end frame member by means of a screw-threaded fastening member which extends through the end frame member to a fixing at the end of the tube.
A suitable screw-threaded member may be a bolt which is introduced through the end frame member into a tapped fixing at the end of the tube.
Preferably a flat end face of the tube or fixing is drawn tightly against a flat face of the end frame member. The fixing may be in the form of a tapped plug secured in the tube.
In another of its aspects the invention provides a contactor element for a rotary biological contactor, the element being apertured to enable a supporting rod to extend through it, and the element comprising a skirt forming a collar bounding the aperture to engage the surface of the rod.
There now follows a detailed description, to be read with reference to the accompanying drawings, of a contactor element for a rotary biological contactor rotor which illustrates the present invention by way of example.
In the accompanying drawings:
Figure 1 shows a three-pack rotor for a rotary biological contactor; Figure 2 is a view in elevation of a contactor element according to the invention;
Figure 3 shows a section taken through a portion of the element showing full height corrugations;
Figure 4 shows a section (on a larger scale than Figure 3) through the element at a flow port;
Figure 5 is a view in the direction of arrow 'A' in Figure 4;
Figure 6 is an axial section through a supporting tube/end frame fixing; and
Figure 7 is a view on Section VII-VII of Figure 2.
A rotor (Figure 1) for a rotary biological contactor comprises three or more packs 10, 12, 14 of contactor discs mounted for rotation together on a shaft 16. Each pack comprises forty-one discs secured between end frames 18, 20.
Each disc is made up of ten similar contactor elements (Figure 2), each forming a generally planar sector of the disc. The ten sectors of each disc lie in a common plane (perpendicular to the shaft 16). They are not directly joined to one another, being supported by axially-extending supporting rods 19 (Figure 6) which extend between the end frames 18, 20 through apertures 22, 24, 26 in the contactor elements. The forty-one discs of the rotor are, therefore, effectively created by ten packs of forty-one contactor elements each, the ten packs being uniformly distributed about the shaft 16. Each contactor element (Figures 2 and 3) is formed from a suitable plastics sheet material (e.g. high density polyethylene). The element is of a corrugated form presenting straight, parallel, equi-spaced elongate ridges 28 over substantially the whole of its area on both sides. The ridges extend at 45° to a radial centre-line of the element. The edge portion 29 of the element, all around its periphery, is turned up to form a reinforcing lip to increase the rigidity of the element.
On one side at least of the contactor element, the ridges are interrupted at intervals along their lengths by portions 30 (Figures 4 and 5) of reduced height forming flow ports 32, providing communication between adjacent channels 34 which are formed on opposite sides of each ridge.
In use of the rotor, the shaft 16 is arranged horizontally, just above the level of waste water in a tank, with the rotor packs 10,12, 14 partially submerged in the tank. As the rotor is rotated, waste water becomes raised from the tank on the surfaces of the contactor elements, as the elements in turn become lifted from the tank. Excess surface water drains off the elements down the channels 34, but drainage is assisted by the flow ports 32 which provide some intercommunication between the channels. Excess water is as a consequence drained more quickly from the contactor elements than would be the case in the absence of such ports, so reducing loadings on the rotor and generally improving efficiency of operation.
Each of the supporting rods 19 is in the form of a tube and is secured at its ends to the end frames 18,20 by a method illustrated by Figure 6. A plug 36 is secured by welding in the end of the tube, the plug presenting a flat end face 38 and having a screw-threaded central bore 40. The end face of the plug lies flat against an opposing inner surface of an associated end frame member 42 and the plugged tube 19 firmly bolted to the member by means of a bolt 44 inserted through the member into the tapped plug. In this manner it is ensured that bending moments are transferred from the tubes 19 to the end frames 18,20 whilst avoiding fretting caused by rotation.
To resist tearing of the contactor elements at the apertures 22,24,26, where the supporting rods 19 pass through, each element is formed (at each aperture) as shown by Figure 7. The sheet is shaped to form a short cylindrical skirt 46 forming a collar bounding the aperture and being of a similar inner diameter to the outer diameter of the supporting rod 19, the element being a close sliding fit on the rod.

Claims

1. A method of securing a contactor supporting tube (19) to an end frame (42) of a rotary biological contactor, the method comprising drawing the tube longitudinally and tightly up to the end frame member by means of a screw-threaded fastening member (44) which extends through the end frame member to a fixing (36) at the end of the tube.
2. A method according to claim 1 in which the tube (19) is drawn up to the end frame member by means of a bolt which is introduced through the end frame member into a tapped fixing (36) at the end of the tube.
3. A method according to claim 1 in which a flat end face (38) of the tube or fixing is drawn tightly against a flat face of the end frame member (42) .
4. A method according to claim 1 in which the fixing (36) is in the form of a tapped plug secured in the tube.
5. A generally planar contactor element for use in a rotor of a rotary biological contactor, the element being of a corrugated form presenting spaced elongate ridges (28) which extend at an acute angle to the intended radial extent of the element and between which channels (34) are formed down which water can drain when the element is raised in use from a waste water tank, ridges on at least one side of the planar element being reduced in height (30) at intervals along their lengths to form flow ports (32) interconnecting adjacent channels.
6. A contactor element according to claim 5 formed of a plastics material.
7. A contactor element according to claim 6 formed of high density polyethylene.
8. A contactor element according to claim 5 in which the ridges (28) extend at 45° to a radial centre-line of the element.
9. A contactor element according to claim 5 in which flow ports (32) interconnecting adjacent channels are formed in ridges (28) on both sides of the element.
10. A rotor for a rotary biological contactor comprising a plurality of generally planar contactor elements according to claim 5.
11. A contactor element for a rotary biological contactor, the element being apertured (22, 24, 26) to enable a supporting rod (19) to extend through it, and the element comprising a skirt (46) forming a collar bounding the aperture to engage the surface of the rod.
PCT/GB1997/001364 1996-05-24 1997-05-20 Method of securing a tube to a frame WO1997045645A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU29063/97A AU2906397A (en) 1996-05-24 1997-05-20 Method of securing a tube to a frame

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9610949.1A GB9610949D0 (en) 1996-05-24 1996-05-24 Rotary biological contactor
GB9610949.1 1996-05-24

Publications (2)

Publication Number Publication Date
WO1997045645A2 true WO1997045645A2 (en) 1997-12-04
WO1997045645A3 WO1997045645A3 (en) 1998-02-19

Family

ID=10794285

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1997/001364 WO1997045645A2 (en) 1996-05-24 1997-05-20 Method of securing a tube to a frame

Country Status (4)

Country Link
AU (1) AU2906397A (en)
GB (1) GB9610949D0 (en)
WO (1) WO1997045645A2 (en)
ZA (2) ZA974381B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6734341B2 (en) 1999-09-02 2004-05-11 Pioneer Hi-Bred International, Inc. Starch synthase polynucleotides and their use in the production of new starches

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1223862A (en) * 1959-05-09 1960-06-21 Fixing feet for furniture elements
US4826343A (en) * 1987-05-06 1989-05-02 Richards Peter S Hard metal screw joint connection between soft metal members
WO1992001636A1 (en) * 1990-07-20 1992-02-06 Severn Trent Water Limited Waste water treatment plant
US5419650A (en) * 1992-09-02 1995-05-30 Hoshino Gakki Co., Ltd. Stabilized pipe fastener using an expandable sleeve

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2118535B (en) * 1982-04-20 1985-10-23 Crane Co Contactor media
GB2195327A (en) * 1986-09-16 1988-04-07 Tuke & Bell Ltd Fluid processing medium
JPH0857492A (en) * 1994-08-19 1996-03-05 Toyo Bio Reactor Kk Rotary disk type treatment device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1223862A (en) * 1959-05-09 1960-06-21 Fixing feet for furniture elements
US4826343A (en) * 1987-05-06 1989-05-02 Richards Peter S Hard metal screw joint connection between soft metal members
WO1992001636A1 (en) * 1990-07-20 1992-02-06 Severn Trent Water Limited Waste water treatment plant
US5419650A (en) * 1992-09-02 1995-05-30 Hoshino Gakki Co., Ltd. Stabilized pipe fastener using an expandable sleeve

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6734341B2 (en) 1999-09-02 2004-05-11 Pioneer Hi-Bred International, Inc. Starch synthase polynucleotides and their use in the production of new starches

Also Published As

Publication number Publication date
WO1997045645A3 (en) 1998-02-19
ZA974385B (en) 1997-12-23
GB9610949D0 (en) 1996-07-31
ZA974381B (en) 1997-12-18
AU2906397A (en) 1998-01-05

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