GB2179259A

GB2179259A - Steam delivery apparatus

Info

Publication number: GB2179259A
Application number: GB8521031A
Authority: GB
Inventors: David J Tompkins; Peter C Epstein
Original assignee: Huntleigh Technology Ltd
Current assignee: Huntleigh Technology Ltd
Priority date: 1985-08-22
Filing date: 1985-08-22
Publication date: 1987-03-04
Also published as: GB8521031D0

Abstract

Steam delivery apparatus comprising a boiler (10) in which water is heated by an element (14) and steam is discharged via a nozzle (11). The steam discharges into primary and secondary chimneys (12, 13), and upon entering each of these, air from the surrounding atmosphere is entrained into the flow of steam. The angle of the secondary chimney may be adjusted relative to the primary and the nozzle may be of adjustable area. The apparatus is used to deliver steam to the nasal area. <IMAGE>

Description

SPECIFICATION Steam delivery apparatus This invention relates to steam delivery apparatus.

The invention is particularly, though not exclusively, concerned with delivering steam for application to the nasal area in a treatment for alleviating certain medical conditions, and in the context it will be appreciated that the word "steam" as used herein refers not just to water but also to other liquids.

The invention provides steam delivery apparatus comprising nozzle means for discharging steam, a first chimneythrough which steam discharging from the nozzle means passes, there being a gap between the first chimney and the nozzle means, through which gap airfrom the surrounding atmosphere is entrained into the flow of steam, and a second chimney through which steam exiting from the first chimney passes, there being a gap between the first and second chimneys, through which gapfurther air from the surrounding atmosphere is entrained into the flow of steam.

By way of example, an embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a view of steam delivery apparatus according to the invention, Figure2 is a detail of an alternative chimney arrangement, and Figure 3 is a detail of a nozzle.

The apparatus shown in Figure 1 comprises a boiler 10 having a steam discharging nozzle 11, a primary chimney 12 and a secondary chimney 13. Water in the boiler 10 is heated here by an electrical element 14, although it will be appreciated that any suitable and controllable alternative could be used. The boiler 10 has a safety pressure relief valve 15.

The primary chimney 12 is spaced from the nozzle 11, and this allows airfrom the surrounding atmosphere to be entrained into the flow of steam discharging from the nozzle into the primary chimney. Similarly, the secondary chimney 13 is spaced from the primary chimney 12 to allowfurther entrainment of air into the steam/airstream.

Figure 2 illustrates the possibility of angling the secondary chimney 13 relative to the primary chimney 12.

Figure 3 illustrates a means whereby the size ofthe nozzle orifice maybe varied by relative movement of the needle 16 in the nozzle orifice.

The entrainmentof airatthe primary chimney inlet has the effect of cooling the steam discharging from the nozzle 11, reducing its velocity and increasing the total mass flow ofthe stream through the primary chimney. The amount of air entrained is dependent upon the ratio of the cross-sectional areas ofthe nozzle orifice and the primary chimney outlet. Thus, any restriction of the primary chimney outlet would have a major effect on the mass flow of the stream and its temperature. The further entrainment of air at the secondary chimney inlet causes a further reduction in the velocity ofthe stream and further reduction in its temperature.The ratio of the cross-sectional areas of the primary and secondary chimneys is less pronounced than that of the primary chimney and the nozzle, so any restriction on the secondary chimney outlet will have less effect on the steam delivered. This means that the apparatus is able to deliver a flow of steam in a way which minimises any change in the temperature ofthe steam which could occur as a result of an external effect, such as masking of the secondary chimney outlet.

Having the secondary chimney angled relative to the primarychimney, as illustrated in Figure 2, prevents the possibility of any slugs of water ejected from the nozzle from being discharged from the second chimney. Instead, these slugs are deposited on the wall of the secondary chimney. It also has the effect of allowing an easier release of the stream discharging from the primary chimney should the flow out ofthe secondary chimney be impeded, with the advantage offurther minimisingthetemperature changes of the stream delivered by the secondary chimney.

The nozzle, primary and secondary chimneys could of course be remote from the boiler, in which case the nozzle could be connected to the boiler via an insulated steam hose.

For a given chimney arrangement, the major factors affecting the temperature of the steam delivered by the apparatus are the nozzle area and the steam pressure in the boiler. If the nozzle area is kept constant, the temperature ofthe steam delivered can be varied by adjusting the steam pressure in the boiler. Alternatively, if the steam pressure is kept constant, the deliverytemperature can be varied by adjusting the nozzle area. The steam pressure can be adjusted by modulating the heat input to the boiler. In the case where the steam pressure in the boiler isto remain constant, this can be done by judicious setting of the pressure reliefvalve. An advantage of this constant steam pressure method is that it minimises the effect of any variation in the heat supply to the boiler. Alternative or additional ways of controlling the steam delivery temperature include altering the relative dimensions of the nozzle and the two chimneys, and modulating the amount ofairthat is drawn into the two chimneys. The latter could be achieved by means of shutters operating around the bases ofthe chimneys.

Claims

1. Steam delivery apparatus comprising nozzle means for discharging steam, a first chimney through which steam discharging from the nozzle means passes, there being a gap between the first chimney and the nozzle means, through which gap air from the surrounding atmosphere is entrained into the flow of steam, and a second chimneythrough which steam exiting from the first chimney passes, there being a gap between thefirst and second chimneys,through which gap further air from the surrounding atmosphere is entrained into the flow of steam.

2. Apparatus as claimed in Claim 1 wherein there is means to vary the angle of the secondary chimney relative to the first chimney.

3. Apparatus as claimed in Claim 1 or Claim 2 wherein there is means to vary the size of one or both oftheairentrainmentgaps.

4. Apparatus as claimed in Claim 1, Claim 2 or Claim 3wherein the nozzle means includes means to control the amount of steam discharged thereby.

5. Apparatus as claimed in any preceding claim and further comprising boiler means for generating steam, to which boiler means the nozzle means is connected.

6. Apparatus as claimed in Claim 5 comprising meansforconnecting the nozzle means to the boiler means remotelytherefrom.

7. Steam delivery apparatus substantially as hereinbefore described with reference to and as shown in the accompanying drawings.