NZ334519A - Apparatus for removing water from compressed gas by immersing coil in cooling fluid - Google Patents

Abstract

Compressed gas (typically compressed air) flows through coil 2 (inlet 3 and outlet 4) which is immersible in cooling fluid 5 contained in housing 6. Inlet 7 and outlet 8 are provided for the cooling fluid. The effect is to separate water vapour from the compressed gas by condensation. Typically the cooling fluid flows through float valve 12, to replenish fluid that has evaporated by fan 13 causing air flow over the fluid surface to effect such evaporation.

Description

20 PATENTS ACT 1953 COMPLETE SPECIFICATION AIR TREATMENT APPARATUS AND SYSTEM 40 I, Anthony James Maher, a New Zealand citizen of 69 Battery Road, Napier, New Zealand do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: r I "WtuUAL PROPERtTo?p>"' I OF N2 1 I 9 2000 L REHPiv/c Our Ref: MAH002 Patents Form No. 5 AIR TREATMENT APPARATUS AND SYSTEM TECHNICAL FIELD This invention relates to improvements relating to the treatment of gas in air drying systems. More particularly, but not exclusively, the present invention relates to an apparatus and system for removing water vapour and contaminants from compressed air systems.

BACKGROUND ART Air contains varying amounts of water vapour and contaminants such as solid particles of oil and/or dirt. This air can cause problems when compressed due in part to water vapour not being as compressible as air. Compressed air containing water vapour and 15 contaminants will reduce in quality and this will become apparent when used in dry air applications such as spray painting, cutting, cleaning, part ejection or positioning. This is because water vapour and contaminants in compressed air lines and systems is known to cause increased wear and maintenance costs on equipment, equipment failure itself, which leads to poor workmanship and rejected work.

Various filtering and drying devices are commonly used to reduce the vapour, oil and solid particles, and other contaminants in compressed air systems. These devices can include coalescent or desiccant filters wherein air is generally directed through media such as, for example, foam, a sintered material, or a membrane. A disadvantage with 25 filtering through a media in the case of compressed air is that the filtering media does not stabilise the water vapour being passed therethrough.

Conventional air drying systems can function reasonably efficiently in average and stable humidity environments. However, in environments with fluctuating humidity, 30 the water to air ratio in compressed air systems can increase with higher water vapour levels such that if the level increases beyond the dew point, undesirable results can 2 occur with a reduction in the quality of the compressed air at the outlet of the system. An air receiver in a standard compressed air system, when under pressure, can accentuate or amplify the fluctuations in humidity such that variations are apparent at the downstream end of the air receiver.

It is an object of the invention to provide an apparatus and/or a system and/or a method of reducing water vapour and contaminants in gas that overcomes at least some of the abovementioned problems, or at least to provide the public with a useful choice.

SUMMARY OF THE INVENTION According to a broad aspect of the invention there is provided an apparatus for reducing the amount of water vapour in gas, the apparatus including a tubular conduit having an inlet to receive compressed gas at a sufficient pressure and an outlet at the downstream 15 end of the conduit, the conduit being substantially encompassed by a coolant, the conduit being configured and arranged with a sufficient number of revolutions for causing significant separation of the compressed gas from water vapour, in use, as it passes through the conduit.

Preferably the apparatus further comprises a sealable housing about the conduit to retain the coolant. Desirably the housing is cylindrical or tubular in shape. Preferably the apparatus further includes a pre-expansion chamber is provided upstream of the inlet end of the conduit. Preferably the coolant is replenished to ensure the coolant is kept at a sufficient operating temperature. Preferably the coolant is water or air.

Desirably the conduit is arranged in a helical coil configuration. Preferably the coil has between 8 to 14 revolutions. Preferably the conduit is a tubular pipe made of made of any suitable thermal conducting material. Preferably the pipe is made of copper, ceramic, glass, or kevlar or any combination thereof.

According to a further aspect of the invention there is provided an apparatus for reducing the amount of water vapour in air including a housing defining a chamber 3 being impervious to air and having an air inlet and an air outlet, and further comprising a mineral element suspended within the chamber such as to cause, in use, compressed air introduced to the chamber to pass about the mineral element and reduce the rate of release of water vapour in the air being released and stabilise the humidity level.

Preferably the composition of the mineral element includes any one or more of the following elements: silicon, aluminium, sodium, magnesium, calcium, chlorine, sodium chloride, and/or potassium. Desirably the mineral element includes any one or more of the following elements: calcium phosphate, calcium sulphate, calcium carbonate and/or 10 iron ore. Preferably the housing is tubular and the chamber is substantially vertically disposed to allow the gas introduced into the body portion to circulate about the chamber.

According to a further aspect of the invention there is provided an air drying system 15 wherein the downstream end of the apparatus of the first aspect is connected to the inlet end of the apparatus of the second aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described by way of example only of preferred embodiments with reference to the accompanying drawings in which: Figure 1: Shows a cut away side view of an apparatus 1 according to a first embodiment of the invention; Figure 2: Shows a cross section of the apparatus of figure 1 through A-A; Figure 3: Shows an air treatment system incorporating the apparatus 1 of figure 1 according to an aspect of the invention; Figure 4: Shows a cut away side view of an apparatus 50 according to a second embodiment of the invention; Figure 5: Shows a cut away side view of a filter 100 in accordance with an aspect of the invention; 4 Figure 6: Shows a cut away side view of a filter 200; Figure 7: Shows a cut away side view of a filter 300; Figure 8: Shows a cut away side view of a filter 400; and Figure 9: Shows a cut away side view of an apparatus 500 according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to figures 1 and 2, an apparatus according to a first embodiment of the 10 invention, is illustrated.

The apparatus 1 of the invention includes a conduit 2 preferably in the form of a pipe. The pipe 2 is made of any suitable thermal conducting material such as, for example only, copper, ceramic, glass, or kevlar, or any combination thereof.

Preferably copper is used as the conduit material as it is relatively inexpensive, durable and pliable, thermally conductive, and a variety of grades are available for different applications.

The pipe 2 has an inlet 3 into which a gas is fed and an outlet 4 from which treated gas exits. It will be appreciated that the apparatus of the invention can be configured to treat gases, and for purposes of clarity of description, and by example only of one embodiment, air will be hereinafter referred to as the substance being treated.

The compressed air being fed into inlet 3 would contain a degree of water vapour, and contaminants such as dirt and oil particles and oil vapour. The pipe 2 is configured and arranged to enable the compressed air being fed into the pipe 2 to be subjected to a centrifugal force. This causes the water vapour to be thrown outward and the contaminant particles to be forced against the inner wall of the pipe 2. The centrifugal 30 force is the result of the creation of a vortex due to the spinning air through the coil travelling at high velocity speed and being under high pressure. This high pressure » instigates the velocity of the air that accelerates as the flow increases. It is considered that the air flowing at the centre of the coil is at a lower temperature than air flowing adjacent the inner wall of the coil and this contributes to condensation.

The pipe 2 can be desirably have a circular or oval cross section. Other cross sections can be used but it will be appreciated that specialised equipment will be required to manufacture such tubing. Preferably a circular cross section is used as it has excellent flow characteristics due to an uninterrupted inner wall and is easily manufactured and readily available. The circumference of the pipe 2 can be of a suitable size such as to match the desirable air flow rate required for efficient operation of the apparatus 1.

The pipe 2 is configured with a plurality of bends sufficient for compresses air to be subjected to centrifugal forces to produce a vortex as it passes through the pipe 2. Preferably the pipe 2 has a coil configuration about the middle section of the pipe 2.

Desirably the coil is helical in shape. Preferably the helical coil has a constant circumference with each turn as seen in figures 1 and 2. It will be appreciated that a large number of shapes may be suitable so as to achieve the results intended with the invention and with achieving a desirable overall shape with the apparatus.

Preferably the coiled section-portion of the pipe 2 has between 8 to 14 revolutions although it will be appreciated that the number of revolutions can vary depending on factors including, for example, the coil shape, circumference of the coil shape, and the desirable range of air pressure/air flow rates through the pipe 2.

The coolant 5 encompassing the pipe 2 assists the water vapour to condense and contaminants to be trapped in the condensate. The air being fed into the pipe 2 is subjected to sufficient forces that allow condensation to occur. The coolant 5 is retained about the pipe 2 by a container desirably in the form of a housing or casing 6. It will be appreciated that the housing does not need to be fully enclosed if the coolant is a form of liquid whereby an open portion of the housing will not cause coolant to 6 escape. Alternatively, the housing may fully encase the pipe 2 as illustrated in figures 1 & 2.

In this embodiment of the invention the coolant 5 is water. Water is readily available 5 and inexpensive. It will be appreciated that any form of gas or substance that has the ability to cool and any means to cool may be used. A cap 7 allows coolant 5 to be added to the apparatus 1 as required. A drainage plug 8 is located at the bottom of the casing 6 to drain the apparatus 1 of coolant 5 as required.

It is desirable to maintain the operating temperature of the coolant 5 within a sufficient temperature range so that the apparatus 1 functions to allow condensation to occur via heat exchange to draw the heat from the vortex and to keep the outer vortex cooler, thus allowing separation of water vapour from the air to result. As the coolant 5 will increase in temperature in operation it is desirable to maintain it at a low temperature.

Although simply running the main water supply through the cap 7, passed the pipe 2 and out through the plug 8 may work to keep the coolant 5 at a desirably low temperature, but it is not a preferred solution. Cooling ponds or cooling towers are an alternative method but are expensive to construct and may result in a much larger apparatus 1, thus being undesirable.

According to the first embodiment, a cooling means in the form of an arrangement including a central area 9 being defined between the divider 10 separating the coolant supply chamber 11 and the coolant 5 encompassing the pipe 2, is desirable.

A tube and valve arrangement 12, similar to the operation of a ball cock valve in a water cistern, operates to maintain the level of coolant 5 surrounding the pipe 2. If the level of coolant 5 falls below a predetermined coolant level, the tube and valve arrangement 12 opens to allow coolant 5 to flow into the lower area, and shuts off when the predetermined coolant level is reached. 7 The predetermined coolant level is considered to be sufficient to allow a flow of air through the central cavity 9. The low pressure central area 9 is an air cavity located above the predetermined coolant level and below the divider 10. An air filter 13 is desirably mounted at one side of the casing 6 adjacent the central area 9 such as, in use, 5 to allow air to flow into the central area 9. An outlet aperture 14 at the opposite side of the casing 6 is connected via a pipe 15 to a pump 16.

It will be seen that the action of the pump 16, in use, draws air in through the air filter 13 and through the central area 9 to maintain the temperature of the coolant 5 to 10 operate within desirable range. Advantageously this operating temperature range of the coolant 5 can be maintained by having a monitoring means in the form of a thermostat 17.

The thermostat 17 can be part of a feedback control means to control the desirable 15 operating temperature of the coolant 5 by regulating the flow of passing ambient or pressurised air in the central area 9. The thermostat 17 will measure the temperature of the coolant 5, and provide a feedback signal to a control means 18. The control means 18 can be pre-programmed with the desirable operating temperature range of the coolant 5. When the control means 18 determines that the minimum temperature is 20 reached it can switch off the pump 16. When the thermostat measures the maximum desirable operating temperature of the coolant the control means can switch on the pump 16 to resume the cooling process.

Optionally, and particularly suitable for temperature conditions where freezing of the 25 coolant 5 can occur, a heating element 19 may be provided in the casing 6 and be integrated with any feedback control means such that if the temperature is at an undesirably low level then the element 19 may operate to increase the temperature of the coolant 5 to within the desirable temperature operating range. A suitable power supply can be used. 8 Optionally a water trap or air filter 20 can be fitted downstream of the outlet 4 to collect coalesced water droplets in the pipe 2. It will be appreciated that any one of the filters as described with reference to any one of figures 5 to 8 can be fitted at either end of the pipe 2 to remove some of the water vapour in the system.

Desirably a pre-expansion chamber 21 is upstream of the inlet 3 to treat the air by lowering the relative humidity of the air prior to the air entering the pipe 2. Optionally a drain leg (not shown) can be fitted to the lower section of the chamber 21 to drain condensate from the chamber 21. It is seen that the chamber 21 is mounted adjacent 10 the inlet 3 and is bulbous and circular in shape, and advantageously can be used as a handle for portability purposes. It is preferable to have a chamber 21 that is round or oval in shape for safety purposes by reducing the risk of chamber failure and possible bursting. The chamber 21 would be more at risk of failure from bursting if it were square or rectangular in shape. It will be appreciated the chamber 21 can be provided 15 external to the casing 6 as shown or at the upstream end of the pipe 2 and within the casing 6.

A mineral element 22, such as is described with any one of figures 5 to 8, can be retained within the chamber 21. To assist with dissipating heat away from the casing 6, 20 heat sink means 23 comprising a plurality of spaced-apart fins is optionally integrated with the casing 6 to allow air to convert between the fins of the heat sink 23. It will be appreciated that it may be desirable to place cooling fans (not shown)a adjacent the heat sink 23 to increase the effective heat transfer away from the sink 23.

In operation, the apparatus 1 is filled with coolant 5 through cap 7 and tube and valve arrangement 12 to a predetermined acceptable level and the supply chamber 11 filled. The pump 16 is connected to the outlet aperture 14 and compressed air fed into the chamber 21 and into inlet 3. The amount of pressure is set to allow the apparatus 1 to function, and can be desirably between 100 and 120 psig.

Compressed air is forced through the pipe 2. The water vapour and contaminants in the air, being of a greater density than air, are subjected to a centrifugal force as it passes through the coils and bends of the pipe 2. The centrifugal force causes the water vapour and contaminants to be thrown against the inner wall of the pipe 2. Heat from 5 the movement with the pipe 2 is transferred into the coolant 5 through the pipe 2. The water vapour and contaminants may be mixed and condense due to a thermal reaction generated by the coolant encompassing the outer wall of the pipe 2. The separation of the air from the water vapour and contaminants occurs from the air, and the water vapour and contaminants can coalesce. The air is forced through the central area of the 10 pipe 2 and reduces in temperature as it moves through the pipe 2.

At the outlet 4 of the pipe 2 the water droplets and contaminants that have coalesced are collected in the trap 20 and the treated air exits the downstream end of the trap 20. The treated air can be of a lower humidity and a lower temperature than the non-treated 15 compressed air entering the inlet 3. This treated air is desirable for applications such as spray painting, cutting, cleaning, part ejection or positioning, and a myriad of other uses.

It is envisaged in an alternative embodiment that the water supplied to the apparatus of 20 the invention can be regularly replaced or flushed through regularly. This alternative apparatus will not require a central area for the flow of air to cool the coolant as the supply of mains cold water will be used to replace the higher temperature of the water in the casing 6.

Referring to figure 3, a system incorporating the apparatus 1 of figure 1 according to an aspect of the invention, is illustrated.

The apparatus 1 is connected between a standard compressor unit 24 and the equipment 25 requiring the treated air exited from the apparatus 1. The equipment can 30 be, for example, a unit for spray painting, welding or cutting. An air trap or air filter 26 collects the water droplets at the exhaust end of the apparatus 1 and additional air filters 27, 28 can be placed at both the upstream and downstream ends of the apparatus 1.

The air filter 13 is advantageously connected to the air intake of the air cavity or central 5 area 9 of the apparatus 1. It will be seen that the air cavity or central area 9 in the apparatus 1 can create a vacuum induction system in conjunction with the compressor unit 24. A process of vapourisation heat is removed from the apparatus 1 as air is drawn into the unit 24. This can increase the water vapour content in the air drawn into the unit 24 and can raise the efficiency of the dehumidifying process when compressed air 10 is passes through the coiled pipe 2. An advantage with this process is that the contaminants in the compressed air can be substantially removed prior to being fed into the apparatus 1.

A further advantage with the system incorporating the apparatus 1 is that the vacuum 15 induction system desirably aids in the cooling of the coolant in the apparatus 1 and increases the water vapour content in the air being drawn into the compressor unit 24 that results in removing some of the contaminants in the compressed air before it is fed into the inlet 3 of the pipe 2.

In an alternative embodiment (not shown) a membrane made of a suitable flexible and resilient material having water repellent properties such as a rubber compound may be located at the predetermined coolant level to baffle and reduce the movement of the coolant 5 in the casing 5. In this alternative embodiment a modification to the valve arrangement 12 would be required so that the coolant 5 can only be released by the valve arrangement 12 into the lower portion of the apparatus 1 and not above the membrane in the cavity area 9.

Referring to figure 4, an apparatus according to a second embodiment of the invention, is illustrated. The materials used for the parts of the apparatus 50 illustrated can be the 30 same as for the first embodiment of the invention. 11 The apparatus 50 includes a conduit or pipe 51 preferably in the form of pipe. The pipe 51 has an inlet 52 into which a gas is fed and an outlet 53. The pipe 51 is configured and arranged to enable the compressed gas being fed into the pipe 51 to be subjected to a centrifugal force. This causes the water vapour and the contaminant particles to be 5 forced against the inner wall of the pipe 51.

The pipe 51 can be of similar construction and configuration as in the first embodiment and the variations are not repeated. A coolant 54 encompasses the pipe 51 to assist the water vapour and contaminants to condense. The air being fed into the pipe 51, in use, 10 is compressed to a sufficient pressure to enable condensation to occur.

The coolant 54 is retained about the pipe 51 by a container desirably in the form of a casing 55. The casing is advantageously cylindrical or round in form, the side view of which is shown in figure 4. The housing 55 is desirably enclosed and as it is preferably 15 cylindrical in form it has additional safety advantages given that the pipe 51 is subjected to high pressures.

In this second embodiment, as in the first embodiment, the coolant 54 is water as it is readily available and inexpensive. A cap 56 allows coolant 54 to be added to the 20 apparatus 50 as required. A drainage plug 57 is located at the bottom of the casing 55 to drain the apparatus 50 of the coolant 54 as required.

It is desirable to maintain the operating temperature of the coolant 54 within a sufficient temperature range so that the apparatus 1 functions efficiently to remove water vapour 25 from the compressed air. Regularly replacing the coolant 54 in the apparatus 50 can be done, or attaching and continuously running mains water supply into the apparatus, past the pipe 51 and out through the plug 57 can be done to keep the coolant at a desirably low temperature.

Advantageously, the operating temperature range of the coolant can be monitored by having a monitoring means in the form of a thermostat 58. The thermostat 58 will 12 measure the temperature of the coolant and provide an indication to a user when the coolant temperature needs to be adjusted. An electric element (not shown) may be used to heat the water in extremely cold ambient air conditions. A suitable power supply can be used and/or an energy source such as steam.

A known type of water trap 59 is desirably fitted at preferably the outlet 53 to collect the coalesced water droplets in the pipe 51. Desirably water droplets and contaminants are automatically discharged from the trap 59.

Desirably a pre-expansion chamber 60 is fitted downstream of the inlet 52 and upstream of the pipe 51 to treat the air by lowering the relative humidity of the air prior to the air entering the pipe 51. Optionally a drain leg (not shown) can be fitted to the lower section of the pre-expansion chamber 60 to drain condensate from the pre-expansion chamber 60. It is seen that the pre-expansion chamber 60 is mounted 15 adjacent the inlet 52 and inside the casing 55, and is bulbous and circular in shape. It will be appreciated that the chamber 60 can alternatively be provided external to the casing 6 at the upstream end of the inlet 52 as shown in figure 1.

It is envisaged within the scope of the invention that the coolant may be a circulating refrigerated gas such as, for example, freon, or a refrigerated gas being fed through a plate or condensator system. Optionally the casing or housing adjacent the conduit or pipe can be provided with a heat sink and/or cooling fan as in figure 1, in use, to dissipate heat away from the casing. The efficiency of the apparatus with reducing the humidity in the compressed air will be most apparent in high humidity conditions. It will be appreciated that the cooling aspects of the apparatus 50 can be adapted with known refrigeration components to ensure the temperature of the coolant 54 is maintained within a suitable operating temperature range.

It will be appreciated the suitable known fittings or couplings can be provided at the 30 inlet and outlet ends of the pipe. It will also be appreciated that the first embodiment of the invention can not function to remove all the water vapour from the air. It functions 13 to remove at least some of the water vapour such that there will be less water vapour in the air at the downstream end of the water trap 20 than in the compressed air being received at the inlet of 3 of the apparatus 1. The same applies for the second embodiment. It will also be appreciated that air filters can be fitted either or both at the 5 upstream and downstream ends of the apparatus of the invention, and that more than one air filter at either end can be used. Preferably the air filters are at the downstream end.

Referring to figure 5, a filter 100 according to an aspect of invention, is illustrated. The apparatus 100 includes a body defining a chamber 101. Desirably the chamber 101 is tubular and vertically disposed. It will be appreciated that tubular and round end curves are advantageous in that they are more resistant to high pressure explosion risks than square and hexagonal shapes with seems, edges or folds at right angles.

The chamber 101 can be made of any durable and resilient material that is impervious to gas, such as, for example, glass, fibreglass or other composite materials, metals, alloys, and/or a plastics material. In this embodiment the chamber 101 is made of glass.

The chamber 101 is adapted to include an inlet 103 and an outlet 104. In this 20 embodiment the gas being introduced into the apparatus 1 is compressed air. For simplicity of description references to the treatment of gas will be with compressed air.

Desirably the chamber 101 is releasably attachable by a threaded portion or other such attachment means to a head 102. The head 102 can be any suitable type having a known configuration of air passageway between the inlet 103 allowing gas to flow into the chamber 101, and a passageway from the chamber 101 to the outlet 104, allowing gas to be released downstream. It will be appreciated that the inlet 103 and outlet 104 are adapted with suitable standard fittings for ease of releasably attaching conduits to the inlet 103 and the outlet 104. # 14 A filter element in the form of a mineral element 105 is positioned within the chamber 101 and attached by any known methods and means. In this embodiment an aperture 106 has been bored through the element 105 and the element 105 mounted by a fastening means 107 to the base section 108 of the filter. The fastening means 107 can 5 desirably be, for example, a suitable plastics material or metal bolt.

The mineral element 105 has been discovered to offer some desirable properties when positioned within the chamber 101. When the mineral element 105 attracts is substantially saturated externally, it can absorb hot airborne water vapour carried into 10 the chamber 101 with compressed air. The element 105 can be cooled consistently by the air flow that can cause the water vapour to condense and be drained from the chamber 101. The water vapour can contain oil contaminants that can also be removed in part. It will be appreciated that some water vapour will still be released into the downstream end of the chamber 101 and that some of this water vapour in the 15 compressed air can be removed by use of a general purpose filter or, for greater efficiency a second mineral composite element filter.

The element 105 desirably releases a substantially reduced rate of water vapour into the air at a substantially constant rate. Advantageously this has the desirable effect of 20 reducing the risk of extreme humidity fluctuations and instead appears to stabilise the humidity level of the gas or air being passed through the filter 100. Condensed water vapour and oil contaminants can be discharged from element 105 in liquid form and drained off. This effect is desirable in oil sensitive processes.

A temperature drop may also be experienced in the chamber 101 that may have the advantageous effect of reducing the likelihood of water vapour condensing in the upstream end of the system from the filter 100. A further advantage with the mineral element 105 is that after repeated use the element 105 does not readily become saturated as with some other known types of filters.

The composition of the mineral element 105 may be a rock, such as varieties of the igneous, metamorphic or sedimentary types, or be synthetic. The element 105 can also be a plurality of small rocks bound together in a retainer. The mineral composition may include a variety of desirable elements in a range of percentages by weight. In one non-5 limiting example, the components can include any combination in a variety of percentages by weight of the following: oxygen, silicon, aluminium, sodium, magnesium, calcium, chlorine, sodium chloride, potassium, and/or iron.

The element 105 can be manufactured or naturally occurring. The factors that assist in 10 the efficient functioning of the element 105 can be likely attributed to the density of the minerals, the coarseness or fineness of the minerals, the mineral type, and the particular combination of element parts. An element 105 with a high density can be seen to function reasonably efficiently. In the case of a manufactured mineral composite element, it can desirably include crystals such as, for example, sodium chloride, 15 calcium phosphate, calcium sulphate, calcium carbonate and iron ore.

It will be appreciated that mineral composite elements can be formed by mixing minerals with a suitable solidifying substance or material such as a resin. The mineral element may be incorporated with an existing sintered material; be a part of a filter 20 element; and/or be positioned adjacent the sintered element. It will be appreciated that the mineral element 105 may be sintered or manufactured with a greater porosity to allow compressed air to flow about the mineral element.

It is further envisaged that the filter body could made from a mineral composite, as with 25 components of the filter such as a centrifugal vane, filter retainer, or other such materials of a filter.

The chamber 101 functions as a pressure drop chamber for the compressed air being introduced into the filter 100. As the compressed air enters through the inlet 4, it is 30 directed through the passageway of the head 102 into the chamber 101. Once in the chamber 101 the air will circulate and pass about the element 102. In doing so some of 16 the water vapour in the air will desirably be absorbed by the element 105, and then the element 105 advantageously releases a reduced amount of water vapour into the air exiting the filter 100 at a substantially constant rate. Further, some of the condensed water vapour and oil falls off the element into the bowl for disposal and can be removed 5 from the chamber 101.

It will be appreciated that the apparatus 1 can be used before or after other known types of air dryers in an air drying system such as refrigerated, chemical or absorbent types, and if desired can alternatively be incorporated into the various embodiments of the 10 invention.

Referring to figure 6, a filter 200 in accordance with a second embodiment of the filter, is illustrated. The second filter is similar to the first filter and aspects will not be repeated.

The filter 200 includes a body defining a chamber 201. Desirably the chamber 201 is tubular and vertically disposed. Desirably the chamber 201 is releasably attachable by a threaded portion 202 or other such attachment means to a head 203.

The head 203 is adapted to include an inlet 204 and an outlet 205 at opposite ends of a passageway 206. The passageway is a cavity adapted to direct compressed air into the chamber 201. The inlet 204 allows gas to flow into the chamber 201 and an outlet 205 allows gas to be released downstream. It will be appreciated that the inlet 204 and outlet 205 can be adapted with suitable standard fittings to releasably attach conduits 25 thereto in a compressed air treatment system.

An insert filter element 207 is desirably fitted within the chamber 201 at the entrance to the chamber 201 from the passageway 206 of the head 203. The filter element 207 is preferably a combination of a known type of filter, for example, it may desirably be a 30 sintered element 207, and a mineral element 208 in accordance with an aspect of the invention. The elements 207, 208 are desirably fastened together by a bolt 209 that 17 passes through the mid section of each filter element 207, 208, and the bolt 209 being attachable to a centrally located section 210 of the base 211.

The base 211 is provided with a plurality of vanes 212 forming a centrifuge. The vanes 5 212 cause the compressed air to whirl within the chamber 201 and be subjected to centrifugal forces to cause separation of the entrained vapour and contaminants from the compressed air, and thereby allow the elements 207, 208 to remove such vapour and contaminants from the compressed air.

Optionally an automatic drain unit 213 is provided at the bottom level of the chamber 201. The drain unit 213 functions to discharge the separated liquid and solid particles (contaminants) after separation from compressed air upon passing the filter element 208. The drain unit 213 allows the discharge of vapour and particles in the air that could otherwise circulate about the chamber about the mineral element 208.

Referring now to figure 7, a filter 300 according to a further aspect of the invention, is illustrated. This third aspect is similar in many respects to the first and second filters 100, 200 and the similarities will not be repeated.

The filter 300 includes a body defining a chamber 301. Preferably the chamber 301 is tubular and vertically disposed. Desirably the chamber 301 is releasably attachable by a threaded portion 302 or other such attachment means to a head 303.

The head 303 is adapted with an inlet 304 and an outlet 305 at opposite ends of a 25 passageway 306. The passageway 306 is a cavity adapted to direct compressed air into the chamber 301.

A plurality of vanes 307 located at the entry to the chamber 301 forms a centrifuge. The vanes 307 cause the compressed air to desirably whirl or spin within the chamber 301 30 and be subjected to centrifugal forces to cause separation of the entrained vapour and contaminants from the compressed air, and thereby allow a sintered element 308, or 18 other known type of element suitable for such use, to remove such vapour and contaminants from the compressed air. The element 108 is desirably fastened together by a bolt 309 that passes through the mid section and being attachable to the head 303.

Optionally a manual, automatic or semi-automatic drain unit 310 is provided at the bottom level of the chamber 301. The drain unit 310 functions to discharge the separated liquid and solid particles (contaminants) after separation from compressed air upon passing the filter element 308. The drain unit 310 allows the discharge of vapour and particles in the air that could otherwise circulate about the chamber 301 about the 10 filter element 308. Preferably an automatic drain 310 is provided.

Advantageously a second chamber 311 is releasably attachable to the head 303 and vertically disposed above the passageway 306. The chamber 311 has an inlet 312 from the passageway 306 and an outlet 313. A mineral composite element 314 is provided 15 in the chamber 311 and functions as a humidity balancer as air and vapour passes through the chamber 311.

Referring now to figure 8, a filter 400 according to a fourth aspect of the invention, is illustrated.

The filter 400 includes a body defining a chamber 401. Desirably the chamber 401 is tubular and vertically disposed. Desirably the chamber 401 is releasably attachable by a threaded portion 402 or other such attachment means to a head 403. The chamber 403 can be desirably interchangeable with chambers of other embodiments of the 25 invention.

The head 403 is adapted to include an inlet 404 and an outlet 405 at opposite ends of a passageway 406. The passageway 406 is a cavity adapted to direct compressed air into the chamber 401. There would be no direct passageway between the inlet 404 and the 30 outlet 405. The inlet 404 allows gas to flow into the chamber 401 and an outlet 405 allows gas to be released downstream. 19 It will be appreciated that the inlet 404 and outlet 405 can be adapted with suitable standard fittings to releasably attach conduits thereto in a compressed air treatment system.

The chamber 401 is adapted to accommodate at least one coiled conduit 407 of desirably a helical shape, with conduit inlets 408 receiving air from the passageway 406 and the conduit outlets 409 being positioned adjacent the lower end of the chamber 401 adjacent a standard drain 410. In this embodiment three conduits are used but it 10 will be appreciated that at one least one conduit can be configured to allow the filter 400 to function. A filter element in the form of a mineral element 410 is positioned within the chamber 401 and attached by metal bolt 412 to the base section 413 of the filter body.

In operation, the coils 407 cause the compressed air to whirl within and be subjected to centrifugal forces causing separation of the entrained vapour and contaminants from the compressed air. This can cause the water vapour and the contaminant particles to be forced against the inner wall of the coils 407. Contaminants will be collected in the condensed water vapour that has been separated from the air. The full contents of the 20 conduit will be discharged into the chamber 401 at outlets 409, and pass the mineral element before being released downstream via outlet 405. Condensed water vapour and contaminants will condense and be drained via drain 410 from the chamber 401.

It will be appreciated that the filters 100, 200, 300, 400 can be incorporated with a 25 dehumidifier as an additional unit in the airflow drying system. In the following embodiment of the invention the use of a filtering element can be incorporated as an integral part of the unit as described with reference to figure 9.

Referring now to figure 9, an apparatus, generally referred to as 500, is illustrated.

The apparatus 500 includes a conduit desirably in the form of a helical pipe 501. The pipe 501 has an inlet 502 into which a compressed gas is fed and an outlet 503. It is considered that the centrifugal force initiated by the first helical turn of the pipe 501 produces a vortex such that the air moving at the centre of the pipe 501 moves more 5 slowly than the air adjacent the inner wall of the pipe 501. It is also considered that the oil and water vapour lines the inner wall of the pipe 501 and can cause the air to hydroplane. The vortex effect experienced by the compressed air passing through the coiled pipe 501 can result in a reasonably efficient heat transfer through the wall of the pipe 501 into the surrounding coolant 504.

A coolant 504 encompassing the pipe 501 assists the water vapour and contaminants to condense. The coolant 504 can be desirably water. The air being fed into the pipe 501 is cooled to a sufficient temperature to enable condensation to occur. The coolant 504 is retained about the pipe 501 by a container desirably in the form of a housing 505. A coolant filler and breather cap 506 allows the coolant 504 to be added to the housing 505 as required and allows additionally functions as a blow off valve for surplus coolant 502. An automatic drainage unit 507 is located adjacent the bottom of the housing 505 to drain coolant 502, as required.

The outlet of the conduit 501 is fed through a filter 508. The filter 508 can be any one of the filters as described in figures 5 to 8. The outlet of the filter 508 is fed into an air expansion line 509 within casing 510. The casing 510 is desirably of a sufficient size to allow air exiting the line 509 to circulate between the housing 505 and the casing 510 desirably in an air pressurised zone 512 until it passes through a mineral filter element 25 511 and exits outlet 516.

The mineral element 511 is contained within a cradle 513 and accessible via a lid 514. It is advantageous to periodically replace the mineral element 511 within the cradle 513. It will be appreciated that the cradle unit 513 can be positioned anywhere to 30 expose the mineral element 511 in the air zone 512. 21 A drain 515 is provided adjacent the bottom of the casing 510 to remove any condensate and contaminants from the bottom of the casing 510.

To aid with stabilising the humidity level of the air, a pre-expansion chamber 517 is 5 configured and arranged at the inlet end of the pipe 501 such that air from, for example, a compressor pump, is fed via chamber inlet 518 through the chamber 517 and into the pipe inlet 502. The air within the pre-expansion chamber can circulate about extension section 519. Extension 519 can additionally serve as a handle for a user to move about the apparatus 500, although it will be appreciated the chamber 517 should desirably be 10 adapted to be secured to the casing 510. A drain 520 can remove condensate from the chamber 517 as required. Brackets 521 fasten chamber 517 to the casing 510.

An advantage with the treated air or gas circulating through the apparatus 500 is that the humidity level is relatively stabilised, surprisingly aided by the mineral composite 15 element 511 located in the pressurised zone 512.

If the resultant dry air floor at the downstream end of the apparatus 1, 50, 500 is required for clear air purposes the air may be rehumidified by mixing it with atomised water and passing it through one of the filters 100, 200, 300,400.

Some known types of dessicant dryer towers retain a chemical composition for drying purposes. It will be appreciated that the mineral composite elements of this invention can be substituted in granular or solid form can be used. Additionally, the mineral element may be mostly emersed in liquid and partially exposed to air for rehumidifying 25 compressed air by the method of topping up a filter 100 with a sufficient level of water to emerse the mineral element and providing a feeding device such as a lubricator to ensure a constant water feed is supplied to the filter 100.

It will be appreciated that standard fittings can be used at any junction between parts of 30 the apparatus and system, and in accordance with accepted safety standards in the industry. It will also be appreciated that the mineral element can be fixedly or 22 releasably attached within a chamber and/or be loose within a suitably reinforced chamber able to withstand the movement of the mineral element or elements within the chamber. The mineral element can comprise a plurality of small elements or one larger element.

Wherein the foregoing reference has been made to integers or components having known equivalents, then such equivalents are herein incorporated as if individually set forth. Accordingly, it will be appreciated that changes may be made to the above described embodiments of the invention without departing from the principles taught 10 herein.

Additional advantages of the present invention will become apparent for those skilled in the art after considering the principles in particular form as discussed and illustrated. Thus, it will be understood that the invention is not limited to the particular 15 embodiments described or illustrated, but is intended to cover all alterations or modifications which are within the scope of the appended claims. 23

Claims (41)

WHAT I CLAIM IS: 33451

1. An apparatus for reducing the amount of water vapour in gas, the apparatus including a tubular conduit having an inlet and an outlet, the conduit being substantially encompassable by a coolant, the coolant being retainable within a housing, the housing being provided with a coolant inlet and a coolant outlet, the conduit being configured and arranged with a sufficient number of revolutions for receiving compressed gas at a sufficient pressure at the inlet end such as to cause significant separation of water vapour from the compressed gas, in use, as it passes through the conduit.

2. An apparatus according to claim 1 wherein the housing is sealable, and wherein the coolant inlet is a releasably attachable plug.

3. An apparatus according to claim 2 wherein the plug is threaded.

4. An apparatus according to claim 1 wherein the coolant outlet is a drainage plug.

5. An apparatus according to any one of the preceding claims wherein the coolant is water.

6. An apparatus according to claim 5 when dependant on claim 1 wherein a breather conduit is attached to the housing to allow coolant to be added and to allow any surplus coolant to be released from within the housing.

7. An apparatus according to any one of the preceding claims wherein the housing is cylindrical or tubular in form and having ends.

8. An apparatus according to any one of claims 1 to 6 wherein the housing is square or rectangular shaped. Intellectual Property Office of NZ 24 2 * MAY 2000 RFCCIVED 334519

9. An apparatus according to any one of the preceding claims wherein a heat sink is provided on the housing. 5

10. An apparatus according to claim 9 wherein a cooling fan is provided adjacent the heat sink.

11. An apparatus according to any one of the preceding claims wherein a thermostatic probe is located within the housing to sense the temperature of the 10 coolant.

12. An apparatus according to claim 11 wherein the thermostatic probe is connected to a control means, the control means being arranged and configured to control the flow of the coolant through the housing to ensure the coolant is kept at a 15 sufficient predetermined operating temperature.

13. An apparatus according to any one of the preceding claims wherein a pre-expansion chamber is provided upstream of the conduit inlet. 20

14. An apparatus according to claim 13 wherein the pre-expansion chamber is located within the housing.

15. An apparatus according to claim 13 or 14 wherein the pre-expansion chamber is adapted with a condensate drainage plug. 25

16. An apparatus according to any one of claims 13 to 15 wherein a mineral element is provided within the pre-expansion chamber. Intellectual Property Office of NZ 25 24 MAY 2000 RECEIVED

17. An apparatus according to claim 16 wherein the composition of the mineral element includes any one or more of the following elements: silicon, aluminium, sodium, magnesium, calcium, chlorine, sodium chloride, and/or potassium. 5

18. An apparatus according to claim 16 wherein the composition of the mineral element includes any one or more of the following elements: calcium phosphate, calcium sulphate, calcium carbonate and/or iron ore.

19. An apparatus according to any one of the preceding claims wherein an air filter 10 is provided at the downstream end of the conduit.

20. An apparatus according to claim 19 wherein the air filter contains a mineral element. 15

21. An apparatus according to claim 20 wherein the composition of the mineral element includes any one or more of the following elements: silicon, aluminium, sodium, magnesium, calcium, chlorine, sodium chloride, and/or potassium.

22. An apparatus according to claim 20 wherein the composition of the mineral 20 element includes any one or more of the following elements: calcium phosphate, calcium sulphate, calcium carbonate and/or iron ore.

23. An apparatus according to any one of the preceding claims wherein the conduit is adapted with between 8 to 14 revolutions. 25

24. An apparatus according to any one of the preceding claims wherein the conduit is arranged in a helical coil configuration.

25. An apparatus according to any one of the preceding claims wherein the conduit 30 is a tubular pipe made of made of any suitable thermal conducting material. 26 Intellectual Property Office of NZ 2 4 MAY 2000 RECEIVED 3^45

26. An apparatus according to any one of the preceding claims wherein the pipe is made of copper, ceramic, glass, or kevlar or any combination thereof. 5

27. An apparatus for reducing the amount of water vapour in gas, the apparatus including a tubular conduit having an inlet and an outlet, the conduit being substantially immersed in a coolant, the coolant being retainable within a housing, the housing being provided with a coolant inlet and a coolant outlet and having means to reduce the temperature of the coolant, the conduit being 10 configured and arranged with a sufficient number of revolutions for receiving compressed gas at a sufficient pressure at the inlet end such as to cause significant separation of water vapour from the compressed gas, in use, as it passes through the conduit. 15

28. An apparatus according to claim 27 wherein the means to reduce the temperature of the coolant includes an air cavity through the housing with an air intake at one end and an air pump at the outlet end of the air cavity.

29. An apparatus according to claim 28 wherein an air filter is located at the air 20 intake of the air cavity.

30. An apparatus according to any one of claims 27 to 29 wherein a membrane is located below the air intake and air cavity outlet. 25

31. An apparatus according to any one of claims 27 to 30 wherein a second chamber is located above the air cavity and, in use, contains coolant, and wherein a valve is associated with the air cavity such as to ensure that a sufficient amount of coolant is retained in the housing. Intellectual Property Office of NZ 24 MAY 2000 RECEIVED W4519

32. An apparatus according to claim 27 wherein the air pump is controllable by a control means that activates the air pump when it senses that the temperature of the coolant has reached a predetermined maximum temperature. 5

33. An apparatus according to claim 32 further comprising a thermostat located within the housing, the thermostat output being connected to the control means.

34. An apparatus according to claim 27 further comprising a heating means located within the housing in the coolant and being activatable if the temperature is 10 reduced to a predetermined minimum temperature.

35. An apparatus according to claim 34 wherein the heating means is connected to the control means, the control means being adapted to activate the heating means when the predetermined minimum temperature is detected. 15

36. An air drying system including the apparatus according to any one of the preceding claims and further including a gas compressor means at the upstream end of the apparatus. 20

37. A method of reducing water vapour from gas or air comprising the steps of: (i) supplying compressed gas into the inlet of a conduit, the coil being configured and arranged with between 8 and 14 revolutions and being immersed in a coolant; 25 (ii) ensuring that a sufficient compressed air pressure is maintained to the inlet of the conduit to cause substantial separation of water vapour from the compressed gas; and (iii) replenishing or replacing the coolant by feeding coolant through a coolant inlet in the housing and draining the coolant through a 30 coolant outlet in the housing. Intellectual Property 28 Office of NZ 2 4 MAY 2000 RECEIVED 33 4 5 1 q

38. A method according to claim 37 further comprising step (iv) of removing condensate from the conduit by a filter means located at the downstream end of the conduit.

39. A method according to claim 37 comprising the further step of detecting the temperature of the coolant by a control means that maintains the coolant within a predetermined acceptable temperature range.

40. A method according to claim 37 substantially as herein described.

41. An apparatus substantially as herein described with reference to any one of the accompanying drawings. ANTHONY JAMES MAHER By his attorneys SCHUCH & COMPANY 29 Intellectual Property Office of NZ 2 4 MAY 2000 RECEIVED