GB2478741A

GB2478741A - Vapour recovery apparatus

Info

Publication number: GB2478741A
Application number: GB1004342A
Authority: GB
Inventors: Brady Collins; Peter John Gee; Chris Prince
Original assignee: PSI INNOVATION Ltd
Current assignee: PSI INNOVATION Ltd
Priority date: 2010-03-16
Filing date: 2010-03-16
Publication date: 2011-09-21
Also published as: GB201004342D0

Abstract

An apparatus 1 for recovering vapour from an industrial device comprises a vapour inlet 7 operative to receive vapour from the industrial device and a centrifugal condenser 31 in communication with the vapour inlet 7. The apparatus further comprises a pump 11 operative to pump vapour from the vapour inlet into the centrifugal condenser and a cooler 19 that in use cools the vapour before it enters the centrifugal condenser 31. The centrifugal condenser comprises a tubular chamber having a radial inlet 41 spaced from the longitudinal axis of the tubular chamber and arranged such that, in use, cooled vapour enters the tubular chamber through the chamber inlet, spins within the chamber around the longitudinal axis 43 of the chamber and condenses on part of the tubular chamber. A condensed vapour outlet 39 is provided through which condensed vapour exits the tubular chamber.

Description

A VAPOUR RECOVERY APPARATUS

AND A METHOD OF RECOVERING VAPOUR

The present invention relates to a vapour recovery apparatus and a method of recovering vapour and particularly but not exclusively relates to an apparatus and method for use with an industrial device of the type comprising, or requiring, fluid from a fluid storage tank.

Many industrial devices comprise a fluid storage tank of fluid used during operation of the device. Such fluid varies from device to device, but may comprise a chemical such as a solvent. The storage tank is typically open to atmosphere so as to be exposed to the interior of a factory building in which the device is located. The fluids typically therefore vapourise in the factory building resulting in a significant quantity of the fluid being lost as fluid vapour, and also creating potentially harmful/dangerous levels of the fluid vapour in the atmosphere of the building.

It has been proposed to minimise these problems by covering the tank.

However, tank covers are not always effective or regularly/reliably used.

Fluid vapour in the atmosphere of the building can be alleviated by using a vapour extraction device such as an extractor fan. However, these do not solve the problem of wastage of the fluid in question, and present a secondary environmental problem of the chemical vapour being pumped in to the external atmosphere. Additionally, the exhaust emissions of a *factory can be monitored and there can be negative cost implications from pumping chemical vapours into the external atmosphere.

According to a first aspect of the invention there is provided a vapour recovery apparatus for recovering vapour from an industrial device, the apparatus comprising a vapour inlet operative to receive vapour from the industrial device, and a centrifugal condenser in communication with the vapour inlet, the apparatus further comprising a pump operative to pump vapour from the vapour inlet into the centrifugal condenser, and a cooler operative to cool the vapour, the centrifugal condenser comprising a tubular chamber having a radial inlet spaced from the longitudinal axis of the tubular chamber and arranged such that, in use, cooled vapour enters the tubular chamber through the chamber inlet, spins within the chamber around the longitudinal axis of the chamber, and condenses on part of the chamber, a condensed vapour outlet being provided through which the condensed vapour exits the chamber.

The condensed vapour outlet may be connected directly, or via intermediary pipework, to a fluid storage tank arranged to collect the condensed vapour for possible reuse in the industrial device, In a preferred embodiment, the cooler comprises a vortex cooler comprising a vortex tube in which driving fluid is pumped into the tube via a radial inlet which serves to spin the driving fluid along the tube to induce a relatively cool fluid flow and a relatively hot fluid flow, the hot fluid flow exiting the cooler, the cold fluid flow being operative to cool the vapour.

Preferably the driving fluid pumped into the vortex cooler comprises a gas.

The driving fluid may comprise compressed air.

The pump may comprise a venturi pump comprising a first inlet in communication with the cooler, a second inlet in communication with the vapour inlet of the apparatus, and a combined outlet, the pump being operative such that driving fluid from the cooler enters the pump via the first inlet creating a vacuum that draws vapour through the second inlet, the driving fluid and vapour exiting the pump via the combined outlet.

The cooler may comprise a double venturi assembly comprising a first venturi through which gas is pumped to create a vacuum that draws in the cleaning liquid vapour, and a second venturi into which warm gas is pumped to create a vacuum that draws in the cleaning liquid vapour-gas flow from the first venturi, the assembly being operative such that the cleaning liquid vapour-gas flow mixes with the warm gas and expands from the second venturi such that the liquid-gas flow is cooled.

Preferably the condensed vapour outlet of the tubular chamber of the condenser is substantially co-axial with the longitudinal axis of the chamber, the tubular chamber comprising a driving fluid outlet, the apparatus being operative such that combined driving fluid and vapour is pumped into the chamber via the radial inlet so as to spin within the chamber, the vapour being spun radially outwardly and condensing on walls of the chamber so as to exit the chamber via the condensed vapour outlet, the driving fluid exiting via the driving fluid outlet, Preferably the condensed vapour outlet is axially spaced from the radial inlet.

Preferably the driving fluid outlet comprises an outlet tube having one end that extends into the chamber to a position adjacent to but spaced from the condensed vapour outlet.

Preferably the chamber is frustro-conical, the chamber tapering radially inwardly from the radial inlet towards the condensed vapour outlet.

Preferably the apparatus comprises electronic control means operative to control the function of the apparatus.

The apparatus may comprise a pressure switch operative to switch off the apparatus when a predetermined vapour inlet pressure is reached.

The apparatus may comprise a valve or valves controlled by the electronic control means and operative to control the flow rate of vapour and/or driving fluid into the chamber.

The apparatus may comprise a timer the output of which is used by the electronic control means to control the valve or valves to restrict or stop the flow of vapour into the chamber in order to allow maximum condensation of the vapour in the chamber to occur.

According to a second aspect of the invention there is provided an industrial device comprising the vapour recovery apparatus of the first aspect of the invention.

The device preferably comprises a fluid storage tank, the vapour inlet of the apparatus being in communication with the fluid storage tank.

According to a third aspect of the invention there is provided a method of recovering vapour from an industrial device comprising steps of pumping vapour from a fluid storage tank of the industrial device to a centrifugal condenser comprising a tubular chamber having a radial inlet spaced from the longitudinal axis of the tubular chamber, cooling the vapour before the vapour enters the chamber, pumping the vapour into the chamber through the chamber inlet so as to spin the cooled vapour within the chamber such that the vapour condenses on part of the chamber, and returning the condensed vapour to the fluid storage tank.

Other aspects of the present invention may include any combination of the features or limitations referred to herein.

The present invention may be carried into practice in various ways, but embodiments will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a view from the side of a vapour recovery apparatus in accordance with the present invention; Figure 2 is a view from the side of another vapour recovery apparatus in accordance with the present invention; Figure 3 is a view from the side of a further vapour recovery apparatus in accordance with the present invention; Figure 4 is a view from the top of the further vapour recovery apparatus of Figure 3; and Figure 5 is a view from the side of the vapour recovery apparatus of Figure 1, with a modified cooling means.

Referring initially to figure 1, a vapour recovery apparatus I is mounted to the top of a fluid storage tank 3. The tank 3 may comprise part of an industrial device (not shown) or may be connected to an industrial device. The tank 3 may be a stand alone tank comprising part of a

factory for example.

The tank 3 comprises a duct 5 from which vapour flows from the tank 3 into the vapour recovery apparatus 1, and a condensed vapour return aperture 7 through which condensed vapour from the vapour recovery apparatus re-enters the tank 3.

The duct 5 is connected, via pipework 9, to a pump 11, which in this example comprises a venturi pump. The venturi pump Ii comprises a vapour inlet 13, a driving fluid inlet 15, and a combined outlet 17.

A cooler 19 is connected via pipework 21 to the driving fluid inlet 15 of the pump 11. The cooler 19, in this example, comprises a vortex cooler comprising an elongate, tubular swirl chamber 21 having a radially orientated driving fluid inlet 23, an axially orientated cool driving fluid outlet 25, and an axially orientated hot driving fluid outlet 27 provided by a peripheral annular gap between the outer wall of the swirl chamber 21 and a conical nozzle 28 at that end of the swirl chamber 21. The driving fluid inlet 23 is connected, via pipework 29 to a source of pressurised gas which in the following example comprises a compressed air supply of the industrial device or the factory in which the apparatus I is used.

A centrifugal condenser 31 is connected, via pipework 33, to the combined outlet 17 of the venturi pump Ii.

The condenser 31 comprises a frustro-conical, tubular chamber having a uniform diameter tubular upper part 35 and a reducing diameter, tapered lower part 37 that leads to a condensed vapour outlet pipe 39. The condensed vapour outlet pipe 39 is in communication with the condensed vapour return aperture 7 of the tank 3.

An inlet to the chamber 31 from the pipework 33 comprises a radially directed inlet aperture 41 at the upper part 35 of the vessel arranged such that gas and vapour enters the chamber 31 in a direction generally perpendicular to the longitudinal axis 43 of the chamber 31. The axis of the aperture 41 is spaced from, and does not intersect, the longitudinal axis of the chamber 31.

A driving fluid outlet duct 45 comprises a uniform diameter duct coaxial with longitudinal axis 43 and which extends through the upper part 35 of the chamber 31, partway into the tapered lower part 37, The lower end of the driving fluid duct 45 is thus spaced above the condensed vapour outlet pipe 39. The upper end of the driving fluid duct 45 functions as a driving fluid exhaust and may comprise an end cap 46 to prevent ingress of water or dust or the like into the duct 45, and/or a pressure release valve (not shown).

In use of the apparatus 1, driving fluid comprising compressed air, controlled by a pressure switch 47, flows along pipework 29 and tangentially into the swirl chamber 21 of the vortex cooler 19 through inlet 23. The compressed air accelerates in the swirl chamber 21 and separates into a hot and a cold air stream. The hot air stream moves radially outwardly within the swirl chamber 21 and exits via the hot air outlet 27. The cold air stream is rebounded by the conical nozzle 26 at the hot air outlet and flows back along the swirl chamber 21 to exit via the cold air outlet 25.

The cold air stream from the cooler 19 enters the gas inlet 15 of the venturi pump Ii and creates a vacuum that draws vapour into the pump 11 through vapour inlet 13 via pipework 9 from storage tank 3.

Continued flow of cooled compressed air from the vortex cooler 19 causes the pump 11 to pump cooled air and vapour along pipework 33 and through radial inlet aperture 41 into the centrifugal condenser chamber 31.

The combined air and vapour gas stream spins within the upper part 35 of chamber 31, about longitudinal axis 41. As more air/vapour enters the chamber 31, the spinning gas stream moves down the chamber 31, that is, in a direction along longitudinal axis 41, into the tapered lower part 37. The vapour and air is mixed by the spinning motion. The vapour part of the gas stream is heavier than the air part of the gas stream and thus is moved radially outwardly by the centrifugal forces generated as a result of the spinning motion so as to contact the tapering wall of the lower part 37 of the chamber 31. The vapour has been cooled by the air sufficiently that the vapour condenses on the tapering wall of the lower part 37 of the chamber 31.

The condensed vapour runs down the tapering wall, through the condensed vapour outlet 39 and re-enters the storage tank 3, through return aperture 7 for reuse.

The remaining air in the chamber 31 is less affected by the centrifugal forces acting on the spinning gas stream and thus remains nearer the longitudinal axis 41 of the chamber 31 where it exits the chamber 31 via duct 45 and is vented safely to atmosphere.

The inlet compressed air stream, and thus the flow rate of air and vapour into the chamber 31 can be controlled as required by an electronic controller via pressure switches and/or valves to ensure that the maximum amount of vapour condensation occurs.

The above described apparatus 1 has relatively low energy consumption and advantageously recovers all or a substantial part of the vapour that would normally be lost to the external atmosphere. The vapour can be recovered directly or indirectly to the fluid storage tank 3 and can be reused. This results in minimal vapour wastage of potentially valuable fluid, and also minimises harmful vapour emissions to the external environment.

The use of compressed air as the driving fluid is an example only and may be preferable if the factory in which the apparatus is used already has a compressed air supply. The apparatus may be provided with its own air compressor if required. Any other fluid may be used instead of air.

A vortex cooler is described as this is efficient and compact. However, any other type of cooler may be used.

A venturi pump is described but any other type of pump may be used.

It is envisaged that the above described apparatus 1 may comprise a single unit containing all of the above components that can be retrofitted to part of existing factory extractor systems if required.

A vapour flow meter may be provided to monitor the flow of vapour through the apparatus i.

Referring to Figure 2 a modified apparatus 101 is shown with like features being given like references to those of the apparatus 1 described above.

The modified apparatus 101. comprises the above components in a self contained module adapted to be mounted, via a single connection, on storage tank 3.

In this example, the module comprises a mounting duct 103 that functions as the vapour inlet to the apparatus 101. The condensed vapour outlet pipe 39 in this example is of relatively narrow diameter and is contained within the mounting duct 103.

The centrifugal condenser 31 is mounted with its longitudinal axis 41 horizontal, that is perpendicular to the axis of the mounting duct 103.

One end of the condensed vapour outlet pipe 39 is adjacent the intersection between the uniform diameter tubular part 35 and the tapered part 37 of the chamber 31. The gas outlet duct 45 in this example is also frustroconical, the end of the duct 45 within the chamber 31 being of narrower diameter than the exhaust end of the duct 45.

The vortex cooler 19 is mounted on one side of the module such that the cool outlet 25 feeds cooled air to a frustro-conical pre-chamber 105. The pre-chamber 105 feeds cooled air to the narrower tapered end of the tapered part 37 of the chamber 31.

The vapour inlet to the chamber 31 is provided by an annular space 107 between the outer periphery of the pre-chamber 105 and the tapered end of the tapered part 37 of the chamber 31.

Thus, as cooled air is fed from the vortex cooler 11, through the pre-chamber 105 and into the tapered part 37, this gas flow draws vapour through the annular inlet 107 and into the chamber 31. The combined air and vapour gas stream spins along the chamber 31 and separates into condensed vapour and exhaust air as described above.

Referring additionally to Figures 3 and 4, a further modified apparatus 201 comprises similar features to apparatus 1 of Figure 1.

However, as with the apparatus 101, all of the key components are arranged in a single module that can be mounted on storage tank 3 via a single mounting which in this example comprises the condensed vapour outlet pipe 39. The vapour inlet pipework 9 in this example begins at a position within the outlet pipe 39 and feeds vapour to an inlet assembly 203.

The inlet assembly 203 comprises an initial centrifugal, frustroconical inlet manifold 205 connected to inlet aperture 41 of chamber 31. A pre-chamber 105 is connected to the inlet manifold 205 and defines an annular vapour inlet 107 therebetween. The vortex cooler 19 feeds cooled air to the pre-chamber 105, which draws vapour through the annular inlet 107, and into the inlet manifold 205 where the oxygen and vapour streams combine and spin along the inlet manifold 205 and into the upper part 35 of chamber 31.

Referring additionally to Figure 5, a modified apparatus 1 is as described above with reference to Figure 1 except that the vortex cooler 19 is replaced by a venturi cooling assembly 219.

Compressed air from conduit 29 is pumped into a first venturi 221 of assembly 219. This creates a vacuum that draws vapour from the tank 3 via pipework 9.

A warm air bypass 223 feeds warm air to a second venturi 225 to create a vacuum that draws the air-vapour flow from the first venturi 221 which mixes with the warm air and expands in conical nozzle 227 that is the outlet of second venturi 225. This expansion generates cooling of the fluid flow which then enters upper part 35 of condenser 31. via pipework 33 as described above.

Claims

CLAIMS1. A vapour recovery apparatus for recovering vapour from an industrial device, the apparatus comprising a vapour inlet operative to receive vapour from the industrial device, and a centrifugal condenser in communication with the vapour inlet, the apparatus further comprising a pump operative to pump vapour from the vapour inlet into the centrifugal condenser, and a cooler operative to cool the vapour, the centrifugal condenser comprising a tubular chamber having a radial inlet spaced from the longitudinal axis of the tubular chamber and arranged such that, in use, cooled vapour enters the tubular chamber through the chamber inlet, spins within the chamber around the longitudinal axis of the chamber, and condenses on part of the chamber, a condensed vapour outlet being provided through which the condensed vapour exits the chamber.
2. The apparatus of claim I wherein the cooler comprises a vortex cooler comprising a vortex tube in which driving fluid is pumped into the tube via a radial inlet which serves to spin the driving fluid along the tube to induce a relatively cool fluid flow and a relatively hot fluid flow, the hot fluid flow exiting the cooler, the cold fluid flow being operative to cool the vapour.
3. The apparatus of claim 2 wherein the driving fluid pumped into the vortex cooler comprises a gas.
4. The apparatus of claim 3 wherein he driving fluid comprises compressed air.
5. The apparatus of any one of the preceding claims wherein the pump may comprise a venturi pump comprising a first inlet in communication with the cooler, a second inlet in communication with the vapour inlet of the apparatus, and a combined outlet, the pump being operative such that driving fluid from the cooler enters the pump via the first inlet creating a vacuum that draws vapour through the second inlet, the driving fluid and vapour exiting the pump via the combined outlet.
6. The apparatus of claim 1 wherein the cooler comprises a double venturi assembly comprising a first venturi through which gas is pumped to create a vacuum that draws in the cleaning liquid vapour, and a second venturi into which warm gas is pumped to create a vacuum that draws in the cleaning liquid vapour-gas flow from the first venturi, the assembly being operative such that the cleaning liquid vapour-gas flow mixes with the warm gas and expands from the second venturi such that the liquid-gas flow is cooled.
7. The apparatus of any one of the preceding claims wherein the condensed vapour outlet of the tubular chamber of the condenser is substantially co-axial with the longitudinal axis of the chamber, the tubular chamber comprising a driving fluid outlet, the apparatus being operative such that combined driving fluid and vapour is pumped into the chamber via the radial inlet so as to spin within the chamber, the vapour being spun radially outwardly and condensing on walls of the chamber so as to exit the chamber via the condensed vapour outlet, the driving fluid exiting via the driving fluid outlet,
8. The apparatus of any one of the preceding claims wherein the condensed vapour outlet is axially spaced from the radial inlet.
9. The apparatus of any one of the preceding claims wherein the driving fluid outlet comprises an outlet tube having one end that extends into the chamber to a position adjacent to but spaced from the condensed vapour outlet.
10. The apparatus of any one of the preceding claims wherein the chamber is frustro-conical, the chamber tapering radially inwardly from the radial inlet towards the condensed vapour outlet.
11. The apparatus of any one of the preceding claims wherein the apparatus comprises electronic control means operative to control the function of the apparatus.
12. The apparatus of claim 11 wherein the apparatus may comprise a pressure switch operative to switch off the apparatus when a predetermined vapour inlet pressure is reached.
13. The apparatus of claim 11 or claim 12 wherein a valve or valves controlled by the electronic control means is provided operative to control the flow rate of vapour and/or driving fluid into the chamber.
14. The apparatus of any one of claims 111 to 13 further comprising a timer the output of which is used by the electronic control means to control the valve or valves to restrict or stop the flow of vapour into the chamber in order to allow maximum condensation of the vapour in the chamber to occur.
15. An industrial device comprising the vapour recovery apparatus of any one of claims 1 to 14.
16. The device of claim 15 further comprising a fluid storage tank, the vapour inlet of the apparatus being in communication with the fluid storage tank.
17. A method of recovering vapour from an industrial device comprising steps of pumping vapour from a fluid storage tank of the industrial device to a centrifugal condenser comprising a tubular chamber having a radial inlet spaced from the longitudinal axis of the tubular chamber, cooling the vapour before the vapour enters the chamber, pumping the vapour into the chamber through the chamber inlet so as to spin the cooled vapour within the chamber such that the vapour condenses on part of the chamber, and returning the condensed vapour to the fluid storage tank.
18. A vapour recovery apparatus substantially as described herein with reference to any one of the Figures.