Patent Application
20130139537
This Application is a continuation application of the Dutch Patent Application Serial Number NL2007923, entitled “Condensate Drain Pan”, to JMK Heating B. V., Helmond, the Netherlands, and Kumagaya Kunststoffen V.o.f., Holten, the Netherlands, filed on Dec. 5, 2011, and the specification and claims thereof are incorporated herein by reference.
Not Applicable.
Not Applicable.
Not Applicable.
1. Field of the Invention
The invention relates to a condensate drain pan in particular for use in combination with a HVAC system, comprising a sump, an inlet and an outlet for gases, in particular combustion gases, as well as an outlet for condensate. The invention further concerns a HVAC system provided with a condensate drain pan according to the invention.
2. Description of Related Art
A condensate drain pan is for instance applied in HVAC systems (heating, ventilation, air conditioning), in particular in heating systems. For instance in a heating system, combustion gases of a boiler flow through a heat-exchanger. Most of the heat of the combustion gases will be transferred to a fluid in the heating system. The combustion gases then flow through a flue. Combustion gases contain water vapor and combustion product gases such as SO2 and CO2. During cooling of the combustion gases the vapor will condensate. The condensate water will contain dissolved gases and is therefore acid. The acid condensate water may react with the drain pan and the flue. In time regular inspection is required and may result in costly replacement of affected parts.
Such condensate drain pan is for instance described in GB 2.425.588. The sump of the condensate drain pan is made of a metal suitable for application in an acid environment, such as aluminum or stainless steel. Still such sump is vulnerable to acid corrosion, in particular for the, above average acid condensate of the flue. GB 2.425.588 therefore provides for a collector device located between the flue and the sump. The collector device is made of non-corrodible or corrosion-resistant material. This known condensate drain pan has several disadvantages. The main part of the sump, in particular the metal part between the heat exchanger and the flue, is still vulnerable to acid corrosion. Although the condensate of the heat exchanger is less acid than that of the flue, it still provides an acid environment. Therefore also this condensate drain pan requires regular inspection. It has to be designed such that inspection is possible, for instance by applying expensive inspection ports in the sump, or by opening the condensate drain pan during inspection. Opening of the condensate drain pan for inspection and replacement of the drain pan will in most cases also require replacement of the sealing. Inspection of the condensate drain pan and replacement of affected parts thereof is therefore expensive. Further, this condensate drain pan consists out of many parts, which makes it expensive and vulnerable for failure. Moreover, the several drainage outlets are vulnerable for obstruction, for instance by calcification or acid disposition. In addition, the design freedom is restricted. The outlet of the sump has to be positioned under the flue. The requirement that the parts of the condensate drain pain should be replaceable, further restricts the freedom of design. For this reason, in general, at least the sump is releasable attached to the flue and the heat exchanger, while the flue and the heat exchanger are supported independent of the sump. The heat exchanger may for instance be placed on a supporting frame.
Further, EP 1 182 408 (A2) recites a heater with an exhaust gas and condensate collecting bath passing directly through a channel in its side wall to the exhaust connection. The bath, the channel and the connection are combined in a one-piece injection-molded connecting component able to be connected by connecting elements to the underside of the cast heat radiator.
However, the above document does not indicate how an outlet can be made using the mold of
WO2009003244 (A1) recites a water heater for heating water including various elements. In an example a water heater having a condensate duct to direct condensate into the water for chemically treating the water is recited.
The document is not considered relevant for the present invention, as it does not relate to a condensate drain pan at all; it only relates to a collection base of plastic. The base itself has no further function.
U.S. Pat. No. 5,476,088 (A) recites methods and apparatus for exhausting flue products and removing condensate from a combustion of air/gas mixtures provide a condensate collecting pan for flue products. That pan is provided with an inlet for flue products and condensate, and with an outlet for flue products spaced from that inlet. That inlet is provided with a larger cross-section for flue product and condensate flow than the outlet. A space is provided in the pan for a flow of flue products from the inlet at a substantially even velocity across the larger cross-section of the inlet to the smaller cross-section outlet. Condensate collecting in that space is removed from the pan.
The above document is silent on the material of the pan. Further no exhaust is provided.
WO2009082090 (A1) recites a heat exchanger of an upward combustion type condensing boiler. The heat exchanger includes a condensed-water tray that discharges condensed water generated from the latent heat exchange unit. A latent heat exchange unit is installed in such a manner that the flow direction of the exhaust gas passing through the latent heat exchange unit vertically coincides with the falling direction of condensed water generated from the latent heat exchange unit.
The above condensate water tray is assembled out of many pieces.
DE 10 2006 026613 A1 recites amongst others a plastic siphon in order to prevent drying up thereof.
Many of the above documents can not relate to a condensate drain pan made of a plastic material, as it is not possible to manufacture such a plastic by molding, specifically by injection molding. Dimensional tolerance of such molding are in the order of less than 1 mm, such as 0.2 mm. However such precise components made of plastic typically have a variation in dimensions of a few mm, such as 2-5 mm, which is fully unacceptable for the intended purpose. Such is particularly the case when parts of plastic need to be attached or combined with other elements, or need to be melted together, such as for outlets and inlets. Also provision of a mold is typically quite expensive.
The present invention intends to solve one or more of the problems of the prior art as described above, and it is in particular an objective of the invention to provide a condensate drain pan that is durable in acid environment.
The condensate drain pan according to the invention is characterized by one or several of the appended claims.
In a first aspect of the invention at least the sump is made of non-corrodible or corrosion-resistant material. The material used is preferably also resistant to acids, such as to a pH of less than 5, preferably less than 3, and can withstand high temperatures, such as up to 120° C. Such sump will not corrode, even not in the aggressive acid environment of combustion gases and condensate of boilers. Inspection of the condensate drain pan is therefore not required and under normal circumstances the parts of the condensate drain pan need not to be replaced. Inspection ports may be omitted and more design freedom is obtained. The position of the outlet for condensate and that of the outlet for combustion gases may be chosen independent of each other.
According to the invention a suitable material may be a chemically inert-synthetic plastics material, such as in particular a thermoplastic elastomer, of which category elastic thermoplastic polymer, such as a copolyester proves to be very suitable. In particular polypropylene and polyphenylene sulphide are suited. These material are not only non-corrosive or corrosion resistant, they also provide a good formability, strength and heat resistance. The choice of a suited polymer is not trivial. As mentioned the polymer should be resistant to a relative high and especially a relative low pH, it should be capable of withstanding high temperature, such as above 100° C., and low temperature (e.g. during transport −20° C.), it should be capable of withstanding expansion and shrinking during temperature variations and temperature cycles, it should not absorb water. Further many polymers cannot be processed using rotation molding. For not too high temperatures polypropylene may be used, for even higher temperature polyphenylene sulphide is a good candidate. In order to have polymers being processed in rotation molding it is preferred to use pellets or granules, preferably pellets of a suitable size having a relatively narrow size distribution, e.g. of 1 sigma of 10% relative, preferably less than 5% relative, even more preferably less than 2% relative. It is noted that the prior art typically relates to use of a metal, such as stainless steel or aluminum. These metals will however corrode, typically at unexpected locations.
The condensate drain pan may be manufactured by rotational molding. Rotational molding provides very smooth surfaces, which facilitates the condensate to stream to the outlet for condensate. Even (large) condensate drain pans with a complicated design may be produced in a single production step. The condensate drain pan may accordingly be one single part, avoiding assembly of parts, sealing thereof and edges that easily get contaminated, the typical places of condensate accumulation and therefore corrosion. The present method provides a condensate drain pan substantially free of stress, having a high durability. The present method also allows for a large variety in shape and size of products. Also the tolerance of e.g. inside dimensions can now be met. Such inside tolerance is in the order of ±0.5% or less, such as ±0.1% (relative). A typical thickness of the condensate drain pan is 2-20 mm, such as 3-10 mm, or 5-8 mm. A thickness of the mold is typically 8-10 mm. The life time of the present condensate drain pan is increased dramatically, such as up to 10 years and longer. The sump may be profiled to further facilitate streaming of condensate toward the outlet opening. According to the invention even the inlets and outlets of gases and condensate may form an integral part of the sump and may be produced in the single production step. The condensate outlet may be shaped as siphon. The invention further provides for the possibility to have an inspection port as integral part of the sump. Such inspection port may be provided with a cover. According to the invention one or more of the inlets, outlets, siphon and inspection port may be provided with, internal or external, thread.
To a further aspect of the invention the condensate drain pan is suitable for placement on a surface. Such condensate drain surface pan does not require attachment to for instance a heat exchanger. The condensate drain pan may in this respect be provided with legs in order to obtain free space under the sump for the outlet and/or the siphon. In a further embodiment of the invention the condensate drain pan has a support surface to support the HVAC system or a part thereof such as a heat exchanger. A support frame for the HVAC system may therefore be omitted. The condensate drain pan may accordingly be provided with reinforcements.
The various aspects of the invention will now be described in more detail and will be elucidated, by way of example only, with reference to the accompanying drawing.
The drawings show in
In
The heat exchanger 1 of
The combustion gases cool down and expand while cooling down in the heat exchanger 1 and in the flue 8. Combustion gases contain water vapor and combustion product gases such as SO2 and CO2. During cooling of the combustion gases the vapor will condensate. The condensate water will contain dissolved gases and is therefore acid. The condensate water will be accumulated in the sump 6 and will leave sump 6 through outlet 12. The acid condensate water may react with the drain pan and the flue. In time regular inspection is required and may result in costly replacement of affected parts. Accordingly all these parts are replaceable attached to the heat exchanger. The sump of the state of art condensate drain pan is made of a metal suitable for application in an acid environment, such as aluminum or stainless steel. Still, such sump is vulnerable to acid corrosion, in particular for the, above average acid condensate of the flue. Therefore, in this prior of art condensate drain pan, a collector device 13 is provided and located between the flue and the sump. The collector device 13 is made of non-corrodible or corrosion-resistant material. This is an expensive, complicated solution and still is not satisfying as it does not solve the corrosion problem of the condensate drain pan in general and as it is still vulnerable for clogging.
The present invention therefore provides a ‘sealed for life’ solution. The embodiment of the invention as shown in
In
In
In
To the person skilled in art it is obvious that the above given embodiments represent only a few of the many possible variations in which the condensate drain pan according to the invention may be embodied. Therefore the embodiments given here must be understood as an elucidation to the appended claims without limiting the scope of the invention. Within the protective scope numerous variations are conceivable. For instance rotation molding also provides the possibility to apply inserts, for instance threaded insert for connection of the condensate drain pan with a heat exchanger.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007923 | Dec 2011 | NL | national |
