WO1995026481A1

WO1995026481A1 - Insulated bath, spa pool, swimming pool, or the like

Info

Publication number: WO1995026481A1
Application number: PCT/NZ1994/000137
Authority: WO
Inventors: Dali Wu
Original assignee: Dali Wu
Priority date: 1994-03-25
Filing date: 1994-12-02
Publication date: 1995-10-05
Also published as: AU1205095A

Abstract

A vessel (8) is provided having a continuous layer of polyurethane insulative foam over substantially the entire outside surface (7) thereof. Vessel (8) may be a bathtub, spa pool, swimming pool, basin, or similar built-in receptacle for holding water for washing or bathing purposes. The polyurethane foam is generated by mixing two or more components in a mixer and spraying the resultant mixture onto outside surface (7). The foam has a density of 10-100 kg/m3, and the ratio of the closed cellular void volume to the total cellular void volume is 90-97 %. A method of manufacturing vessel (8) having a continuous layer of polyurethane insulative foam over substantially the entire outside surface (7) thereof is also disclosed.

Description

T

Insulated bath, Spa Pool, Swimming Pool, or the like.

This invention relates to bath tubs, spa pools and like vessels in which water is held for bathing or washing purposes.

Bath tubs, when filled with water at a suitable washing temperature, required periodic topping up with hot water to maintain the temperature at the desired level. With spa pools, swimming pools and the like the water temperature is maintained using a heat source, such as, for example, an electric heating element.

10

It has been noted that, depending on the material from which the bath tub is made, from 50% to 70% of water heat loss occurs through the walls. A similar proportion of heat loss takes places through the walls of spa pools, sw___τπ_ing pools, and

15 such vessels.

The recognition that heat loss occurs through the vessels walls is not new; various techniques in the past have been tried to irάnimise this loss. For example, blocks of polystyrene

20 foam or other insulationg material have been glued to the outside surface of the vessel. All prior attempts to prevent heat loss have their disadvantages. Namely, the insulation material is costly and time consuming to apply, and because the insulation material is applied in sections gaps and

25 overlapping occurs warm and cold spots.

It is an object of the present invention to provide a vessel having walls which reduce heat loss as compared with existing similar vessels, and to provide a method for manufacturing

30 the same. Accordingly, in a first broad aspect of this invention there is provided a vessel having a continuous layer of insulative material over substantially the entire outer surface thereof.

Preferably, the insulative material is a foam.

Desirably, the insulative material is 5 millimetres to 200 millimetres thick, expediently 10 millimetres to 100 millimetres thick.

Preferably, the foam is polyurethane based.

Conveniently, the foam density is 5 kilograms per cubic metre to 500 kilograms per cubic metre, expediently 10 kilograms per cubic metre to 100 kilograms per cubic metre.

Desirably, the cellular void volume of the foam is from 1% to 97%, expediently 70% to 95%.

In a second broad aspect of this invention there is provided a method of manufacturing a vessel having a continuous layer of insulative material over substantally its entire outer surface, the method comprising:

a) ensuring that the outer surface of the vessel is substantially clean and free of loose materials; b) applying a liquid polyurethane mix to the outer surface of the vessel; and, c) allowing the polyurethane liquid to foam and then cure.

Preferably, the liquid polyurethane mix is sprayed onto the outer surface of the vessel.

Desirably, the liquid polyurethane is mixed in the spray gun as it is dispensed. Conveniently, foaming of the liquid polyurethane is achieved by mixing into the liquid polyurethane a low boiling point liquid.

Alternatively, the polyurethane foam can be generated by mixing two or more components in the dispensing spray gun, the components reacting to produce the polyurethane foam. Expediently at least one of the components is a hydroxyl and another of the reactant components is a isocyanate.

Preferably, the mix of liquid polyurethane is controlled to produce a foam thickness of from 5 millimetres to 200 millimetres thick, expediently of from 10 millimetres to 100 millimetres thick.

Conveniently, the mix of liquid polyurethane is controlled to expand to produce a foam density of from 5 kilygrams per cubic metre to 500 kilograms per cubic metre, advantageously of from 10 kilograms per cubic metre to 100 kilograms per cubic metre.

Desirably, the mix of liquid polyurethane is controlled to produce a cellular void volume of from 1% to 97%, expediently of from 70% to 95%.

Conveniently, the mix of liquid polyurethane is controlled to produce an expanded and curing time of from 1 second to 1 hour, more preferably of from 10 seconds to 5 minutes.

In a third broad aspect of this invention, there is provided a vessel produced according to the second broad aspect above.

The term "vessel" as used herein is to be understood to refer to bath tubs, spa pools, swimming pools, and basins and like built-in receptacles for holding water for washing or bathing purposes. in order that the invention may be more fully understood, and its advantages appreciated, various aspects will now be described with reference to the accompanying drawings, in which:

Figure 1 is schematic illustration of polyurethane liquid mix being applied to the outer surface of a spa pool shell prior to foaming commencing; and,

Figure 2 is a schematic illustration of the spa pool shell of figure 1 after the polyurethane mix has expanded and cured.

As illustrated in the drawing, prior to spraying the polyurethane mix the component parts of the mix are stored separately in containers 1 and 2. Feed lines 3 and 4 draw the component parts to the mixer 5 and atomised as the mixture pass out through the spray nozzle of the spray gun 6. As the polyurethane mix lands on the outer surface 7 of the spa pool 8 it will begin to foam. Once foaming is substantially complete the foam will start to cure, forming a rigid cellular mass.

The spray gun 6 preferably incorporates control valves to adjust the relative volumes of the component parts entering the mixing chamber of the spray gun 6.

The desired thickness of the foam can be adjusted by varying the volume of polyurethane mix applied over any given area of the spa pool shell, and also by adjusting the relative mix of the component parts of the polyurethane mix.

For example, where the polyurethane is physically foamed, by mixing polyurethane liquid with a low boiling point liquid, such as Freon whose boiling point is 23.8°C, the foaming rate and amount can be varied by varying the volume of Freon per unit volume polyurethane liquid.

Similarly, where the polyurethane foam is produced in a chemical reaction the foam characteristics can be varied by adjusting the quantity of water in the hydroxyl reactant component.

By way of example only, a workable two component polyurethane mix is as follows:

Component A: Poly-toyl Poly-diisocyanate (PAPI) 84

Component B: Mannitol polyether poly-alcohol 50

Polyether poly-glycerine o-7 Potassium oleate 0-3

DMCHA 2-3

D P-30 3-5

Freon 11 23-25

Organic silicone oil L580 1.5 - alyl polyether poly-glycerine 0.2

- Methylstyrene 0.2

In use such a polyurethane foam would have the following characteristics: time for mixing to occur - 10 seconds; time for foaming to initiate - 15 seconds; time to substantially complete expansion 120 seconds; final foam density - 33 kilograms per cubic metre; heat conductivity - 0.016Kcal/m.c.h.

In the above example Mannitol polyether poly-alcohol and

Polyether poly-glycerine can be replaced with Poly-m-phenyl ether. Such a substitution anables the quantity of Freon to be reduced or, if different foam characteristics are acceptable, dispensed with entirely.

By variation of the component mix to slow the reaction rate producing the foam it would be possible to brush or roll the polyurethabe mix onto the vessel outer surface.

The present invention also application to already installed hand basins, bath tubs, spa and swimming pools. In this regard, such vessels are generally mounted in a closed cabinet or cavity. A measured amount of liquid polyurethane mix can therefore simply be sprayed into the cabinet or cavity. As the polyurethane mix foams the foam takes on the shape of the available space, thereby providing the desired layer of insulative material.

Additional advantages of the present invention will become appearent to those skilled in the art after considering the principles in the particular form as disscussed and illustrated.

Accordingly, it will be appreciated that changes may be made to the above described embodiments of the invention without departing from the principles taught herein.

Finally, it will be understood that this invention is not limited to the -_mbodiments described or illustrated, but is intended to cover all alterations, additions or modifications which are within the scope thereof.

Claims

1 The improvements in or relating to bath tubs and the like comprising a method of provide a vessel having a continuous layer of insulative foam over substantially the entire outer surface thereof.

2 The improvements in or relating to bath tubs and the like of claim 1 wherein the foam is polyurethane based. The polyurethane foam is generated by mixing two or more components in the mixer, the components reacting to produce the polyurethane foam. At least one of the reactant components is a hydroxyl and another of the reactant components is an isocyanate.

3 The improvements in or relating to bath tubs and the like of claim 2 wherein the components are mixed in the mixer, then the mixture of the components are sprayed onto the outer surface of the vessel. The mixture of the components react on the vessel and begin to foam. The foam is sticked onto outer surface of the vessel.

4 The improvements in or relating to bath tubs and the like of claim 1 and 2 and 3, with the said foam, the closed cellular void volume to the total cellular void volume is 90% - 97%.

5 The improvements in or relating to bath tubs and like of claim 1 and 2 and 3 and 4, the said foam density is 10 kilograms to 100 kilograms per cubic metre.

6 The improvements in or relating to bath tubs and the like, the claim 1 and 2 and 3 and 4 and 5, the term "vessel" as used is to be understood to refer to bath tubs, spa pools, swimming pools, and basins and like built-in receptacles for holding water for washing or bathing purposes.