GB2178080A - Ventilation of water closet pan - Google Patents

Abstract

Apparatus for ventilating a water closet pan comprises an extractor unit coupled via a conduit to an aperture in the flush pipe.

Description

SPECIFICATION Apparatus and method for ventilating a water closet pan This invention relates to apparatus and method for ventilating a water closet pan.

The desirability of ventilating water closet pans to remove disagreeable odours has long been recognised, and I am aware of various prior proposals.

In United Kingdom patent application 2072232A there is disclosed the provision of an air passageway positioned between the inlet and outlet legs of the siphon body; the lower end of the air passageway is connected to the interior of the outlet siphon leg, and thus with the pipework leading to the water closet pan; whilst the upper end connects to a conduit communicating with an extractor fan so that in use and when the outlet leg and pipework are in open communication, offensive odours can be removed from the water closet. This proposal requires a specially manufactured siphon body designed to locate the passageway in relation to the siphon legs, together with a suitably located connection between the passageway and the outlet leg such that the usual float valve provided in the cistern is not obstructed in its movement.Furthermore, space is needed to permit the connection of the conduit communicating with the extractor fan, and this is not always available; this arrangement thus requires specially constructed cisterns. The conduit to the extractor unit needs to pass through the cistern wall which may not be a convenient positioning in relation to the extractor unit, and in any case again requires a specially manufactured cistern. This arrangement is unsuitable for retro-fit to existing toilets.

I am also aware of United Kingdom patent application 2096662A which discloses providing a small chamber at the rear of the pan to house a motordriven fan, the fan drawing air from the pan by way of a special integral duct whose upper end is located above the flush water supply. The fan discharges the air into the toilet wastepipe. Such an arrangement requires a specially manufactured pan having the integral duct, which in turn means that additionally the arrangement is unsuitable for a retrofit. Furthermore, the positioning of the motor-driven fan behind the pan makes access difficult, with the result that its use is likely to be restricted to "open-plan" combined bathroom and toilet suites, unless the industrial or domestic owner is prepared for the pan as a whole to be removed merely for normal fan and motor servicing.

A dis-advantage of the arrangement of 2096662A is the possibility of valve failure and the consequent direct connection of the sewers to the toilet area, which may be in a bathroom.

It is an object of my invention to provide an apparatus and method for ventilating a water closet pan which does not require modification of the cistern or pan.

It is a further object of my invention to provide apparatus and method for ventilating a water closet pan which can be simply added to existing installations as a retro fit.

Thus according to my invention I provide apparatus for ventilating a water closet pan comprising coupling means in the downspout between the cistern and the water closet pan, and conduit means connecting the coupling means to an extractor unit.

The coupling means can be a T-junction or equivalent fitted into an existing downspout, or the downspout itself can be provided in T-form. The coupling means will be shaped and dimensioned so that water flowing from the cistern to the pan will not flow along the conduit means.

Conveniently my extractor unit is positioned on an inside wall of the building, with a replaceable filter so that the air drawn from the pan can be freshened and discharged inside the building, so avoiding the energy waste of discharging heated internal building air to atmosphere, whilst also avoiding the cost and possible inconvenience of providing ventilating holes through the building wall. For such an internal location, in a preferred embodiment I provide an extractor unit comprising a motor-driven impellor, which has the advantage of being relatively quiet in operation; and wherein the rotatable impellor is separate from the motor by which it is driven so that the exhaust air is not drawn through and around the motor. In an alternative embodiment I can however use a fan.

The filter is conveniently of bonded activated carbon. If required, the filter unit can have an attachment for holding a scented pan should for instance a domestic user want the freshened air emerging from the filter additionally to carry a selected fragrance.

According to a further feature of my invention I provide a method of ventilating a water closet pan which includes the steps of introducing a volume of water at a first position into a downspout, the water discharging from a second position out of the downspout into a water closet pan, sealing said first position so that water introduction is terminated, and withdrawing air from said downspout whilst said first position is sealed whereby air is also withdrawn through the downspout from the pan.

The invention will be further described by way of example with reference to the accompanying drawings.

Figure 1 is a schematic side elevation of apparatus according to my invention; and Figure 2 is a section of a T-connection in a downspout.

My invention is applicable both to the closed coupling system in which the cistern mounts directly on the water closet pan 4 and which would then require a T-extension piece (Figure 1), and to the open coupling system with a downspout and which would then require an inserted T-piece (Figure 2).

Water cistern 2 feeds water closet pan 4 by way of T-piece 6; pan 4 is of a conventional construction with internal passageways 8 feeding separate outlets 10 to the toilet bowl 12. Toilet bowl 12 is connected to waste pipe 14, and has seat 16 and lid 17.

Intermediate the cistern 2 and pan 4 is a T-piece 6, with the leg of the "T" joined to a conduit 22, leading to impellor 24 driven by an electric motor.

To the outlet of impellor 24 is fitted a filter unit 26 having a filter element of bonded activated carbon, with at the downstream end of the filter unit 26 a scented pad 30.

The electric motor for impellor 24 is activated by wires 28 from the toilet light switch 32, though in an alternative embodiment a switch operated independently of the light can be provided such as a conventional wall-mounted switch, or a door-jamb switch; alternatively a pressure-operated switch positioned either under a toilet mat or under the toilet seat could be used if the local safety regulations permit.

Air from the T-piece 6 is discharged by impellor 24 through filter unit 26 and thereby freshened into the atmosphere adjacent the toilet, so removing obnoxious odours from closet pan 4 and rendering the toilet area suitable for re-use without embarrassment or discomfort. In an alternative embodiment air from impellor 24 could be discharged externaliy of the building or toilet area, but if this internal building air has been heated, as in winter, or in cooler climates, then this is wasteful of energy.

In the embodiment of Figure 2, part of downspout 7 is replaced by a T-piece 9 having leg 11 connected to conduit 22.

I have found that bonded activated carbon blocks 4" x 3 1/2" x 1" are suitable for use with an air stream of 18 cubic feet per minute; as granulated carbon in similar sized perforated steel trays or in plastic trays. Preferably the impellor is based on the foreward-curved multivane centrifugal principle, conveniently with dual voltage motors so that they can be run from both 240v and 110v supplies (50HZ), and used at between 15% and 85% of their free discharge capability - preferably at about 60% of their free discharge. The impellor unit will be mounted with the motor shaft being horizontal.

Since I prefer to set the motor speed to suit the installation, I recommend the insertion of a wirewound resistor in series with the motor, typically in the range of 100 - 2500 ohms and rated at between 5 and 20 watts depending on the voltage reduction, so the resistor needs to be mounted in a position allowing adequate cooling. Progressive control of impellor performance can be achieved by the use of a variable resistor.

For a single larger impellor drawing air from a plurality of pans, as in a factory installation, I may control the impellor motor by an autotransformer, either of the fixed tapping or continuously variable type, though in an alternative arrangement I may use a solid state electronic speed controller if the installation does not demonstrate harsh running with peaks in vibration and noise.

In general, the air delivery for any particular application is directly proportional to impellor rotational speed. Preferably the impellor casing is of aluminium, for rigidity, strength, appearance and ease of cleaning, though welded steel pressings can be used. For domestic applications I recommend a double inlet, double width unit, since the two relatively large inlets and large outlet allow a low impellor speed, so that the operating speed is quickly reached, aerodynamic noise is kept to a minimum, and mechanical vibrations are less pronounced. An impellor speed of between 800 and 930 revolutions per minute may be used. There is an approximate square law relationship between the volume flow rate through the ducting and the fan pressure required to achieve that flow rate so that to double the flow rate requires four times the fan pressure.

It will be appreciated that in the embodiment of Figure 1 in which the cistern conventionally sits directly on the water closet pan 4, 1 will provide a Tpiece 6 shaped and sized so that the cistern can be lifted sufficiently to mate sealingly with one crosspiece 40 of the "T", with the opposed cross-piece 42 mating sealingly with the connection to the pan 4, the stem of the "T" as above being connected to the duct 22 leading to impellor 24. To insert such a preformed T-piece is a simple plumbing or DIY ("Do-it-yourself" handyman) operation, whilst the electric wiring to the motor is also a simple operation.

Thus I have provided an apparatus and method suitable both for initial fitting and for retro-fitting, simple to install and service, effective in operation, permitting continued use of the conventional expensive toilet fittings, such as cistern and pan, yet of minimum additional cost.

I foresee that my apparatus and method could have applications in hospitals, trains, ships and aircraft in addition to houses, factories, hotels and clubs.

In domestic installations particularly, as an alternative to fitting the impellor unit internally of the toilet area, I could mount it above the ceiling on the joists, and with the outlet air fed either back through the ceiling into the toilet area or an adjacent area, or through the roofing to discharge to atmosphere. The alternative "joist" mounting may be preferred if the impellor unit is thought too unsightly or too heavy for wall or other "internal" mounting.

In yet a further alternative arrangement, to avoid the use of the carbon filter, the impellor outlet could be connected, as by a T-piece, into the cistern overflow pipe, so discharging the "foul-air" direct to atmosphere through pipework which is already fitted but seldom used.

Claims (12)

1. Apparatus for ventilating a water closet pan comprising coupling means in the downspout between the cistern and the water closet pan, and independent air extractor unit, and conduit means connecting the coupling means to the air extractor unit.

2. Apparatus as claimed in Claim 1 in which the coupling means is of T-form, the stem of the T being joined to the conduit means, the head of the T being connected to the cistern and pan, means being provided to prevent water flowing from the cistern to the pan also flowing along the stem.

3. Apparatus as claimed in Claim 1 in which the coupling means is a retro-fit unit, having end connections on the T-head shaped and sized to fit the cistern water outlet and the pan water inlet respectively.

4. Apparatus as claimed in any of Claims 1-3 in which the extractor unit is positioned on an inside wall of the building housing the water closet pan.

5. Apparatus as claimed in Claim 4 in which the extractor unit is associated with an air freshening unit, so that air from the conduit means can be recirculated in the building.

6. Apparatus as claimed in any of Claims 1-5 in which the extractor unit includes a motor-driven impellor.

7. Apparatus as claimed in Claim 6 in which the impellor is separate from the motor so that air from the conduit means is not drawn through and/ or around the motor.

8. Apparatus as claimed in Claim 5 and as claimed in Claim 6 when dependant on Claim 5 in which the air freshening unit includes a filter of bonded activated carbon.

9. A method of ventilating a water closet pan which includes the steps of introducing a volume of water at a first position in a downspout, the water discharging from a second position out of the downspout into a water closet pan, sealing said first position so that water introduction is terminated, and withdrawing air from said downspout whilst said first position is sealed, whereby air is also withdrawn through the downspout from the pan.

10. A method as claimed in Claim 10 wherein said air is withdrawn by an extractor unit, the extractor unit being energised upon an illuminating source for the closet pan being energised.

11. Apparatus constructed and arranged substantially as described with reference to the accompanying drawings.

12. A method of ventilating a water closet pan substantially as described with reference to the accompanying drawings.