NZ200616A - Gas-fuelled blowing heater - Google Patents

Description

200616 Priority Date(s): Complete Specification Filed: h Class: J?tS&&. /$&<&/€& Publication Date: || ). jAPR. J9$?..

P.O. Journal, No: Patents Form No; 5 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION "FORCED AIR GAS-FUELLED HEATER" I, GRAHAM RICHARD DeCLIFFORD, an Australian citizen, of 28 Conn Street, Ferntree Gully, Victoria 3156, Australia, hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- 200616 forced air gas-fuelled This invention relates to a / -heater and has been devised particularly though not solely for the heating of large enclosed areas such as factories or warehouses.

In the past large enclosed areas such as factories or warehouses have commonly been heated by a large central heater such as an oil heater which heats the air and blows it out into the large enclosed area.

Such installations have the disadvantages that they are expensive to manufacture and run and that they reach a high operating temperature which can be dangerous to those in the vicinity. Furthermore such heating units have been known to give off toxic fumes which make them unsuitable for use in heating areas where people are working and other applications such as chicken farming, without a heat exchanger. It is also a disadvantage of existing heaters that they are normally a permanent installation and therefore cannot be utilized in a number of different situations. Existing heaters are normally also provided with a flue to discharge the toxic gases from the burner, which requires that the heater be permanently installed and provided with a flue installation which is also expensive. Furthermore installations of this type have a significant heat loss through the flue and are therefore relatively inefficient in use.

It is therefore an object of the present invention to provide a heater which will obviate or minimize the foregoing disadvantages in a simple yet effective manner " J " 2.00616 or which will at least provide the public with a useful choice.

Accordingly the invention consists of a gas fuelled heater including a cylindrical shroud, a blower arranged to blow air through said shroud, a gas burner located within said shroud downstream from said blower , and a deflector plate connected to said shroud, said deflector being positioned across a portion of said shroud downstream from said burner, said gas burner having a substantially conical configuration and being oriented such that the wider end thereof is located downstream of the remainder of the burner.

Preferably said burner is substantially conical in shape having its open wider end facing downstream.

Preferably the downstream end of said burner is provided with a lip on the inner face thereof which is substantially parallel to the axis of the shroud.

Preferably said deflector plate is circular and positioned across the middle section of said shroud leaving a peripheral passageway between the deflector plate and the shroud.

Preferably said shroud is double walled downstream from said burner.

Notwithstanding any other forms that may fall within its scope one preferred form of the invention will now be described by way of example only with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a gas heater according to the invention from the inlet end of the heater, Fig. 2 is a partially cut away side elevation of the gas heater shown in Fig. 1, Fig. 3 is a cross-sectional elevation on the line 00616 ,-r ( 3-3 of Fig. 2, Fig. 4 is a' cross-sectional elevation on the line 4-4 of Fig. 2 showing one form of burner used in the gas heater, Fig. 5 is a cross-sectional elevation on the line -5 of Fig. 4, Fig. 6 is a cross-sectional elevation on the line 4-4 of Fig. 2 showing an alternative form of burner used in a gas heater according to the invention, and 10 Fig. 7 is a cross-sectional elevation on the line 7-7 of Fig. 6.

In the preferred form of the invention a gas heater is constructed as follows: The heater comprises a cylindrical shroud 1 15 having an open inlet end 2 and an open outlet end 3. The inlet end 2 is provided with a protective grill (not shown) and just inside the inlet is positioned a blower fan driven by an electric motor to suck air . through the inlet 2 and blow the air through the shroud 20 1 and out of the outlet 3.

The heater is portable and is mounted on a pair of wheels 4 and supported at the outlet end by a pair of legs 5 formed integrally with a manoeuvring handle 6. , ^ The handle and wheels are so positioned that the heater 2 5 is balanced for easy movement on the wheels by lifting and holding the handle 6. It is a further feature of the heater that the handle is positioned at the outlet end 200616 of the heater so as to deter people from moving the heater when the heater is operating. r The heater is provided -with a burner 7 located downstream from the blower and the burner is supplied with a gas air mixture through a mixing valve 8A. The mixing valve SAis supplied with gas which is preferably liquid petroleum gas through a pair of solenoid shut off valves located in housing 9A. The solenoid shut off valves are actuable by two sensors, one located directly above the electric motor driving the blower so as to detect any overload condition in the motor and shut off the gas supply, and -the other located adjacent the outlet 3 so as to shut off the gas supply if the heater outlet temperature exceeds a predetermined dangerous value.

The burner 7 is centrally located in the cross-section of the shroud 1 and is substantially conical in shape as may be seen in Fig. 5. The burner has a cylindrical gas inlet portion 8 having a threaded inlet aperture 9 which receives the gas air mixture supply pipe 10. The burner then flares outwardly in a conical portion 11 terminating in a lip 12 which is parallel to the axis of the shroud and located on the trailing edge 21. It has been found that the lip is important in controlling the flame in the burner. In the preferred form of the invention as shown in the drawings the lip has a depth of 6 millimetres when used in a burner having an overall internal outlet diameter of 184 millimetres. 200616 The burner is provided with an igniter and with a flame sensor which automatically cuts off the gas supply if the r flame should go out.

In an alternative form of the invention the burner may be provided with an outwardly turned lip 20 at the trailing edge 21 as can be seen in Figs. 6 and 7. In this alternative burner configuration the gas is introduced through aperture 22 into the inlet portion 23 of the burner which then flares outwardly in' a conical portion 2 4 terminating in the outwardly turned lip 20 of the trailing edge 21.

In both alternative burner configurations a diffuser plate 25, 26 is provided to control the flow of gas/air mixture and the burners^ are provided with electrical igniters and flame sensors (not shown) arranged to shut off the solenoid shut off valves if the flame goes out.~ The portion of the shroud downstream from the burner is provided with a double wall by providing an inner liner 13 spaced from the shroud 1 by an air gap 14. The double walled portion keeps the outside of the heater comparatively cool so as to avoid burning anybody who might touch the outside surface of the shroud or so as to prevent any risk of fire damage.

A deflector plate 15 is provided located downstream from the burner 7 and across the mid portion of the section of the shroud. In the preferred form of the invention the deflector plate has a circular periphery centrally 200616 located in the cross section of the shroud and is conical in configuration j^ith the peak 16 of the cone facing towards the burner 7. The deflector plate is mounted on a strut 17 located edge on to the air flow in the 5 peripheral areas so as to cause the least possible air flow resistance.

It has been found in use that the combination of the particular burner configuration and the incorporation of the lip 12 or 20, used in con junction with the deflector , 10 plate 15 arranged and located as shown results in a flame which is easy to control and has a short flame length which does not protrude beyond the outlet 3 from the heater. In this manner the heater is safe in use and does not pose a fire hazard or a danger to people 15 moving in the vicinity of the heater.

The lip on the edge of the burner may be either an inwardly turned lip as shown at 12 in Fig. 5 or alternatively may be an outwardly directed lip as shown at 20 in Fig. 7. In either case it has been found important to incorporate 20 a lip on the trailing edge 21 of the conical burner to promote adequate mixing in the combustion chamber which is defined by the burner, the deflector plate and the shroud. It is important to slow down the combustion gases in this area to achieve complete burn of the gas and 25 to this end the lip on the trailing edge of the burner promotes complete combustion and keeps the flame tip hot for a complete burn. Complete combusion is important 200616 to control the level of noxious emissions and it has been found that without the lip (in either configuration) the levels of NC>2 and CO in the gases emitted from the burner escalate dramatically.

The configuration of the heater according to the invention gives an open flow pressurised combustion chamber 17 in which mixing of the burning gases is promoted to give a clean burn to the gas and control the amount of noxious emissions from the heater.

The burner is preferably fueled by liquid petroleum gas and it has been found in practice that a 99.9% burn of fuel can be achieved in a heater which is completely portable and does not require a flue. The heater is also very clean in operation which reduces maintenance and also means that there are no toxic gases issuing from the heater which accordingly may be used directly into situations such as chicken batteries without the necessity to use a separate heat transfer unit.

In this manner a gas heater is provided which is simple and cheap to manufacture, is light and portable and therefore may be used in a.number of different applications, and is very safe in use both because of the fact that there are no toxic gases emitted and also because the external temperature of the unit itself and also of the heated air coming from the outlet 3 is controlled as to prevent burns to anybody moving in the area of the heater. 2006 16 The heater has a large number of applications such as factory heating, timber, fruit, tobacco and grain drying, general manufacturing processes for heating and drying, hot houses, mushroom farming, sports 5 stadiums, paint drying, ski lodge change rooms, poultry sheds, piggeries, public halls and swimming pool domes. If desired the heater may also be used in conjunction with a heat exchanger to heat liquid and may in this application be used for example in the heating of a 10 swimming pool.

Claims (14)

- 10 - 200616 WHAT I CLAIM IS:

1. A gas-fuelled heater including a cylindrical shroud, a blower arranged to blow air through said shroud, a gas burner located within said shroud downstream from said blower, and a deflector plate connected to said shroud, said deflector being positioned across a portion of said shroud downstream from said burner, said gas burner having a substantially conical configuration and being oriented such that the wider end thereof is located downstream of the remainder of the burner.

2. A gas-fuelled heater according to claim 1, wherein said conical configuration is substantially hollow, and is open-ended at said wider end.

3. A gas-fuelled heater as claimed in claim 2, wherein the periphery of said wider end of said burner is provided with a substantially radially outwardly extending lip.

4. A gas-fuelled heater as claimed in claim 2, wherein the periphery of said wider end of said burner is provided with a lip on the inner face thereof, said lip having an inner peripheral surface substantially parallel to the axis of the cylindrical shroud.

5. A gas-fuelled heater according to claim 2, 3 or 4, wherein a diffuser plate having a plurality of peripheral grooves or notches therein is located within said burner, the grooves or notches forming with the inner surface of said burner a plurality of passages for the flow of a gas/air mixture.

6. A gas-fuelled heater as claimed in any preceding claim, wherein said deflector plate has a circular periphery and is positioned across the middle section of the shroud, leaving ann annular passageway between the deflector plate and the inner periphery of the shroud. - 11 - 200616

7. A gas-fuelled heater as claimed in claim 6, wherein said deflector plate has a conical configuration, the apex of the conical configuration being upstream from the remainder of the deflector plate.

8. A gas-fuelled heater according to claim 7 , wherein said conical configuration is hollow.

9. A gas-fuelled heater as claimed in any preceding claim wherein the sizing and positioning of the burner and the deflector plate in proportion to the size of the cylindrical shroud and the airflow rate therethrough result in an open flow pressurised combustion chamber being formed within the shroud between the burner and the deflector plate.

10. A gas-fuelled heater according to any preceding claim, wherein the portion of said cylindrical shroud downstream from said burner has a double wall.

11. A gas-fuelled heater according to claim 10 wherein the deflector plate is connected to the inner wall of said double wall of the shroud.

12. A gas-fuelled heater as claimed in any preceding claim incorporating a burner constructed and arranged substantially as described herein with reference to Figs. 4 and 5 of the accompanying drawings.

13. A gas-fuelled heater as claimed in any preceding claim incorporating a burner constructed and arranged substantially as described herein with reference to Figs. 6 and 7 of the accompanying drawings.

14. A gas-fuelled heater when constructed, arranged and operable substantially as described herein with reference to the accompanying drawings.