GB2150926A

GB2150926A - Gas transfer equipment

Info

Publication number: GB2150926A
Application number: GB8332476A
Authority: GB
Inventors: Charles Patrick Schofield
Original assignee: National Research Development Corp UK
Current assignee: National Research Development Corp UK
Priority date: 1983-12-06
Filing date: 1983-12-06
Publication date: 1985-07-10
Also published as: GB8332476D0

Abstract

An aeration assembly comprises a sequence controller 11, a suction pipe (inlet) 12, an outlet discharge pipe 13, an air exhaust pressure regulator 14, a vacuum/pressure pump 15, an electric motor device 16 and an input/output flow control valve 17. In operation, slurry is sucked into the tanker through the valve 17 and is aerated by air from the pump 15. When the aeration has been competed, the pump is used to expel slurry through pipe 13 and into the store 20. <IMAGE>

Description

SPECIFICATION Gas transfer equipment The invention relates to gas transfer equipment and in particular, but not exclusively, to equipment for aerating slurries of animal excreta.

Conventional slurry tankers have no aeration facility. They simply suck in the slurry at source and then discharge it (untreated) on to the land.

According to a.first aspect of the present invention, there is provided gas transfer equipment comprising a vessel, input means for introducing raw slurry or liquid into the vessel, treatment means for introducing a flow of gas or vapour into the slurry or liquid in the vessel, and expulsion means for expelling the treated slurry or liquid from the vessel e.g. to a slurry store or on to the land.

Conveniently, the input means comprises a conventional pump, but in a currently preferred embodiment, the vessel is a pressure vessel e.g. as provided by a slurry tanker, and the input means comprises evacuation means for exhausting the volume of the vessel or the space above any slurry or liquid already in the vessel thereby to suck the raw slurry or liquid into the vessel.

Conveniently, the expulsion means comprises a conventional pump but in a preferred embodiment the vessel is a pressure vessel and the expulsion means comprises means for pressuring the space above the slurry or liquid in the vessel thereby to force the slurry or liquid out of the vessel.

Conveniently, the flow of slurry into and out of the vessel is through an inlet and outlet valve provided by one and the same device but if desired separate inlet and outlet valves may be provided for this purpose.

Conveniently, the gas transfer equipment comprises aeration equipment arranged so that oxygen, air or other suitable oxygen-containing gas or vapour is introduced into the slurry or liquid through aeration means.

Conveniently, where the vessel is a pressure vessel, then the equipment includes removal means whereby, when the vessel is pressurised, at least a proportion of the gas or vapour leaving the vessel may be permanently removed for further use and/or may be recirculated for further treatment of the slurry or liquid in the vessel.

The invention also includes an aeration assembly comprising aeration equipment according to the present invention and a store for slurry or liquid treated in the aeration equipment.

In one such aeration assembly, gas or vapour leaving the vessel is used to mix the slurry or liquid in the store and/or continue treatment of the slurry or liquid there.

Alternatively, the gas or vapour leaving the vessel could also be used to aerate composts of solid or separated livestock wastes.

According to a second aspect of the invention, there is provided a method of controlling slurry odour which comprises the steps of intensively aerating raw slurry for a period of time by bubbling oxygen, air, or other suitable oxygen-containing gas orvapourthrough it.

Conveniently, in this case, the method includes the steps of bubbling oxygen, air, or other suitable oxygen-containing gas or vapour through the slurry continuously, periodically removing a proportion of the treated slurry and replacing the treated slurry removed in this way by a proportion of raw slurry.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawing.

Thus referring now to the drawing, gas transfer equipment according to the present invention comprises a tanker 10, a sequence controller 11, a suction pipe (inlet) 12, an outlet discharge pipe 13, an air exhaust pressure regulator 14, a vacuum/ pressure pump 15, an electric motor device 16 and an input/output flow control valve 17.

In operation, the valve 17 is set to the "slurry in" position and the pump 15 to "suck". With regulator 14 closed, slurry (18) flows from a pit 19 into the tanker 10 which in this embodiment provides the pressure vessel referred to above. In variations, a static vessel may be used instead.

When the tanker is sufficiently full, valve 17 is closed and the pump 15 is set to "blow". Regulator 14 is then opened and the slurry is aerated.

When the aeration has been completed, valve 17 is set to "slurry out" and regulator 14 is closed. Pump 15 is left at the "blow" setting. This causes slurry to be expelled through pipe 13 and into a store 20.

The exhaust air from regulator 14 mixes slurry in the store to maintain solids in the slurry in suspension orto resuspend them prior to disposal.

As explained above, the sequence controller 11 is used to control when the pump 15 is to evacuate or pressurise the tanker and also when the inlet/outlet valve 17 is to be opened or closed in conjunction with the pressure regulator 14. This enables the tanker to be used as both a slurry treatment and a slurry pumping device.

Enhanced pressures can be maintained within the tanker during treatment to speed the rate of oxygen transfer into the slurry.

The gaseous exhaust from the tanker can be used to mix the slurry in the store, and possibly also to continue the aeration process there.

Alternatively, the gaseous exhaust could be used to aerate composts of solid or separated livestock wastes.

The equipment of the present invention could be installed and run at relatively low cost and the tanker would be quickly released for conventional use to empty the store as necessary.

The aeration process described above relies for its effectiveness on bacteria which oxidise odorous components in the slurry in the presence of oxygen.

It will be appreciated that slurry aeration as above described should reduce the odour in the slurry considerably and that continual or repeated aeration of the treated slurry e.g. in the store, should not be necessary for this purpose for a period of time governed by the effectiveness of the initial treatment.

In modifications (not shown) of the illustrated embodiment, the vacuum/pressure pump 15 is re placed by a compressor to provide the aerating flow and the slurry 18 is forced into the tanker or other vessel (which need not in this case be a pressure vessel) by a conventional pump provided at the lower end of pipe 12.

In other modifications, the input/output valve 17 is replaced by two separate valves, one in the inlet pipe and one in the outlet pipe.

As well as providing gas transfer system for aerating slurries, the equipment of the present invention can be used as what amounts to a large bore pump for transferring slurry from one place to another e.g. without treatment, or further treatment, in the slurry-containing vessel of the equipment.

Claims

1. Gas transfer equipment comprising a vessel, input means for introducing raw slurry or liquid into the vessel, treatment means for introducing a flow of gas or vapour into the slurry or liquid in the vessel, and expulsion means for expelling the treated slurry or liquid from the vessel.

2. Equipment as claimed in Claim 1 in which the vessel is a pressure vessel and the input means comprises evacuation means for exhausting the volume of the vessel or the space above any slurry or liquid already in the vessel thereby to suck the raw slurry or liquid into the vessel.

3. Equipment as claimed in Claim 1 or Claim 2 in which the vessel is a pressure vessel and the expulsion means comprises means for pressuring the space above the slurry or liquid in the vessel thereby to force the slurry or liquid out of the vessel.

4. Equipment as claimed in any preceding claim in which the flow of slurry into and out of the vessel is through an inlet and outlet valve provided by one and the same device.

5. Equipment as claimed in any preceding claim in which the gas transfer equipment comprises aeration equipment arranged so that oxygen, air or other suitable oxygen-containing gas or vapour is introduced into the slurry or liquid through aeration means.

6. Equipment as claimed in any preceding claim where the vessel is a pressure vessel and including removal means whereby, when the vessel is pressurised, at least a proportion of the gas or vapour leaving the vessel may be permanently removed for further use and/or may be recirculated for further treatment of the slurry or liquid in the vessel.

7. An aeration assembly comprising aeration equipment as claimed in Claim 5 or Claim 6 and a store for slurry or liquid treated in the aeration equipment.

8. An aeration assembly as claimed in Claim 7 in which gas or vapour leaving the vessel is used to mix the slurry or liquid in the store and/or continue treatment of the slurry or liquid there.

9. An aeration assembly as claimed in Claim 7 or Claim 8 in which gas or vapour leaving the vessel is used to mix the slurry or liquid in the store and/or continue treatment of the slurry or liquid there.

10. Equipment substantially as hereinbefore described with reference to and/or as illustrated in the accompanying drawing.

11. A method of controlling slurry odour which comprises the steps of intensively aerating raw slurry for a period of time by bubbling oxygen, air, or other suitable oxygen-containing gas or vapour through it.

12. A method as claimed in Claim 11 including the steps of bubbling oxygen, air, or other suitable oxygen-containing gas or vapour through the slurry continuously, periodically removing a proportion of the treated slurry and replacing the treated slurry removed in this way by a proportion of raw slurry.