AU2129302A - An evaporator tray - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

(ORIGINAL)

Name of Applicant: Actual Inventor: Address for Service: Invention Title: Mijell Enterprises Pty Ltd BELL, Michael James DAVIES COLLISON CAVE, Patent Attorneys, 1 Little Collins Street, Melbourne, Victoria 3000.

An evaporator tray Details of Associated Provisional Application: No: PR3750/01 The following statement is a full description of this invention, including the best method of performing it known to us: Q:\OPER\ARL\2507566 56.DOC 6/3/02 P:\OPERArl EVAPORATOR TRAY mplNee.do-25/02/02 -1- AN EVAPORATOR TRAY The invention relates to evaporator tray for air-conditioning systems. In particular, the invention concerns evaporator trays for use in split air-conditioning systems.

Air-conditioning systems are used in both domestic and commercial buildings to regulate the internal temperature of areas within the building. Split air-conditioning systems are Sooften employed in such buildings. In a split air-conditioning system, the "cold" side is located within the building, while the "hot" side is located outside the building. The "cold" side usually comprises an expansion valve and the cold coil for cooling the interior of the building. The "hot" side usually comprises a compressor and a hot coil for dissipating heat oo o. from the interior of the building. The "hot" side is frequently referred to as the condensing unit. The primary benefit of a split air-conditioning system is that it reduces noise within the building as the louder condensing unit is located outside.

A consequence of any air-conditioning system is that the "hot" side or condensing unit causes water to condense around the condensing unit as it dissipates the heat from the hot coil. This condensed water is usually removed from the condensing unit by storing the water in a tray so that it is exposed to the ambient environment. This allows the water to evaporate under natural conditions. Alternatively, a drain is provided to run the condensed water from the condensing unit away from the air-conditioning system and the building.

While the above described techniques for removing condensated water are effective in domestic dwellings and commercial buildings, difficulties arise in the case of multi-storey high rise buildings. In this context, high rise buildings include offices, blocks and residential units. Due to the relatively small size of individual offices or units, natural rates of evaporation in ordinary trays are often too slow to remove condensated water from the condensing unit. This leads to the build up of condensed water which may potentially overflow onto the balcony or exterior space supporting the condensing unit. Furthermore, the condensed water may stagnate and encourage the growth of bacteria or pests. Draining condensed water along the side of the building is unsightly and the relatively warm P:\OPER\Ar\EVAPORATOR TRAY omjplcc.dm-25A12Y02 -2temperature of the water may encourage the growth of mould and fungus. Draining the condensated water for example via the floor of individual balconies is both difficult (in ensuring a large enough channel to drain the water) and causes inconvenience to the tenants of any balconies below.

It has also been proposed to use trays of greater depth to compensate for the larger volume of water. However, these trays are difficult to install as there is often a small space for the tray to lie beneath standard condensing units in split air-conditioning systems.

0.: According to an aspect of the invention, there is provided an evaporator tray for an airconditioning system, comprising: o a tray for receiving fluid from the air-conditioning system; a heating element for evaporating fluid in the tray; a sensor for detecting the level of the fluid in the tray; means to activate the heating element when the sensor detects a predetermined level of fluid in the tray.

By incorporating the heating element into the tray so that it can be activated by the sensor, the evaporation tray according to the invention promotes the rate of evaporation. It has been found that in most cases fluid in the tray from the condensing unit of the airconditioning system is substantially removed. This avoids causing inconvenient or unsightly removal of condensed water as well as avoiding the build up of fluid and potential overflow.

Preferably, the heating element is located in the tray. The sensor preferably extends in part into the volume of the tray.

It is preferred that the heating element is located in close proximity to the bottom surface of the tray. Preferably, the heating element is located to one end of the tray. The heating element is preferably powered by an electric source. The heating element may be a metal coil.

P:\OPERMAriREVAPORATOR TRAY wmpct.d-26)2A)2 -3- Preferably the tray has a cover for shielding the heating element from tampering or debris.

It is preferred that the cover is removable from the tray. The cover is preferably perforated to allow evaporated fluid to escape.

The means for activating the heating element is preferably an electric circuit. It is preferred that the electric circuit is connected to the sensor.

ooo To assist in understanding the invention, a preferred embodiment of the invention will now be described (by way of example only), with reference to the drawings of which: Figure 1 is a perspective view of an evaporation tray according to the invention; Figure 2 is a plan view of the evaporation tray of Figure 1; Figure 3 is a side view of the evaporation tray of Figure 1; *.*Figure 4 is an end view of the evaporation tray of Figure 1; and Figure 5 is another perspective view of the evaporation tray of Figure 1 illustrating the use of a cover for the heating element.

0 Referring to Figure 1, there is provided a preferred embodiment of the evaporation tray according to the invention. The invention comprises a tray 1 to receive water from the condensing unit in an air-conditioning system. The tray 1 is usually made from stainless steel and rectangular in shape. A heating element 2 in the form of a metallic coil is mounted in close proximity to the bottom of tray 1 at one end. A sensor 3 for detecting the water level in tray 1 extends into the volume of the tray 1. Sensor 3 is located near heating element or coil 2. While the sensor 3 is located close to the heating element 2, it may be located anywhere in tray 1 so long as it extends in part into the volume of the tray 1.

Both the heating element 2 and sensor 3 are electrically connected to electric circuit which is in the form of a terminal box. A heat sink 6 is provided between terminal box and heating element 2. A power supply lead 7 (not shown) is used to provide power to the terminal box 5, sensor 3 and heating coil 2.

P\OPER\Ar\EVAPORATOR TRAY wopdet.dc-Z6/flM2 -4- The evaporation tray according to the preferred embodiment of the invention is installed by sliding it underneath the condensing unit in a typical air-conditioning system, which is located exteriorly of the building. In operation, condensed water is allowed to drip into tray 1 as the air-conditioning system cools air from inside and releases or dissipates the heat via the condensing unit outside the building. Condensed water will pool and build up within tray 1. When the sensor 3 detects that the level of water in the tray 1 is at predetermined level (as set by the position of the sensor the electrical circuit or terminal box 5 activates heating coil 2. Heating element 2 then heats the water in the tray 1 until the water evaporates and the water level in tray 1 falls below sensor 3.

Once the water level falls below sensor 3, the electrical circuit 5 switches off the heating coil 2. Residual heat produced by the heating coil 2 as it cools down also assists in continuing to promote the rate of evaporation of the water in tray 1.

o Alternatively, electrical circuit 5 can be adjusted so that it has a variable "run on" time.

This means that heating coil 2 is activated for a set amount of time until an acceptable amount of water remains in the tray 1. This alternative method can lead to more residual heat being developed in and around the tray 1.

It can be seen that the sensor 3 can determine the level of water in tray 1 and thereby activate heating element 2 via electrical circuit 5. This ensures that excess condensated water is removed conveniently without the need for drains. In addition, there is no chance of overflow of condensated water or for any water to encourage growth of bacteria or mould in the tray 1.

Referring to Figures 2 and 5, the embodiment may employ a stainless steel cover 4.

Stainless steel cover 4 is fitted onto tray 1 over heating element 2. The cover 4 is removable from the tray 1 and is perforated along its length. The cover 4 prevents the user's hands from inadvertently touching the heating coil 2 when it is in operation. The perforations allow evaporated water to escape from the tray 1. In addition, the cover 4 P:\OPER\ArI\EVAPORATOR TRAY completc.doc.-26A)2/02 may also assist in preventing of debris collecting on the heating element 2.

The stainless steel tray may measure 900 mm long x 400 mm wide x 60 mm deep. The terminal box 5 is connected with a one metre 3-core power lead which passes through a waterproof conduit fitting. When connected to a flexible corrugated conduit, it is totally Sweatherproof. The evaporator tray may also be earthed.

.I

The heating element 2 is usually rated at 1000 watts 240 volts and is designed to evaporate oeooo approximately 1 litre of water per hour, depending on atmospheric conditions and the nature of material beneath the tray. The sensor or probe is 5 mm above the bottom of the tray.

o The tray, cover and coil are usually made from stainless steel to inhibit rusting and to make the evaporator tray suitably resilient to damage in operating conditions. While the heating element is confined to one end of the tray, it may be adapted to extend along the whole length of the tray or a substantial portion of the tray.

It has been found that the balconies of multi-storey buildings usually have a lean to allow for the drainage of rain water. Accordingly, the preferred embodiment takes advantage of this fact by arranging the heating element to be at the end of the tray to which the condensated water will naturally pool.

The heating element and sensor can be arranged in different configurations. For example, the heating element can be located outside or beneath the tray, so long as it heats the fluid in the tray. The sensor may be an optical sensor and therefore need not extend into the tray to determine the fluid level.

It is understood that various modifications, alterations, variations and additions to the construction and arrangement of the embodiment described herein are considered as falling within the ambit and scope of the present invention.

P:\OPER\Al\EVAPORATOR TRAY clnlpIe..doc-25/0V2/ -6- Throughout this specification and claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that the prior art forms part of the common general knowledge in Australia.

o *o oo

Claims (9)

1. An evaporator tray for an air-conditioning system, comprising: a tray for receiving fluid from the air-conditioning system; a heating element for evaporating fluid in the tray; a sensor for detecting the level of the fluid in the tray; means to activate the heating element when the sensor detects a predetermined S•level of fluid in the tray.

2. An evaporator tray according to claim 1, wherein the heating element is located in the tray. .o

3. An evaporator tray according to claim 1 or claim 2, wherein the sensor extends in part into the volume of the tray.

4. An evaporator tray according to any one of claims 1 to 3, wherein the heating •element is located in close proximity to the bottom surface of the tray. An evaporator tray according to any one of claims 1 to 4, wherein the heating element is located at one end of the tray.

6. An evaporator tray according to any one of claims 1 to 5, wherein the tray has a cover for shielding the heating element from tampering or debris.

7. An evaporator tray according to claim 6, wherein the cover is removable from the tray.

8. An evaporator tray according to claim 6 or 7, wherein the cover has perforations to allow evaporated fluid to escape. P:\OPERMA r E VAPORATOR TRLAY mplct e~doc-25AUM -8-

9. An evaporator tray according to any one of the preceding claims, wherein the means for activating the heating element is an electric circuit. An evaporator tray according to claim 9, wherein the electric circuit is connected to the sensor. An evaporator tray according to any one of the preceding claims, wherein the heating element is a metal coil.

12. An evaporator tray substantially as described with reference to the drawings and/or examples. DATED this 26th day of February, 2001. MIJELL ENTERPRISES PTY LTD by DAVIES COLLISON CAVE :-Patent Attorneys for the Applicant