Improvements relating to gas heaters

Abstract

 A gas heater comprising a furnace (12) having a roof (12a), means (14a) for firing the furnace, means for feeding the products of combustion from the furnace (12) into a temperature reducing chamber (21) and means (24) to feed products of combustion which has been reduced in temperature in said chamber (21) from said heater.

Description

[0001] This invention relates to a gas heater.

[0002] An object of the invention is to provide a new and improved gas heater.

[0003] According to the invention we provide a gas heater comprising a furnace, means for firing the furnace, means for feeding the products of combustion from the furnace into a temperature reducing chamber and means to feed the reduced temperature products of combustion from the heater.

[0004] Air may be introduced into the temperature reducing chamber to dilute and cool the products of combustion.

[0005] The furnace and temperature reducing chamber may be located within a shell there being an air space between the shell and the furnace and temperature reducing chamber and means for feeding cooling air through said space to cool the furnace and temperature reducing chamber.

[0006] Said cooling air may provide said air introduced into the temperature reducing chamber.

[0007] The means to fire the furnace may comprise a grate within the furnace and means to feed solid fuel to the grate.

[0008] Preferably means are provided to feed fuel downwardly through the shell and air space to the furnace and onto the grate and said means may comprise a fuel feed tube extending downwardly through the shell, air space end into the roof of the furnace.

[0009] A solid fuel feed means may be provided within the tube to feed fuel onto the grate.

[0010] A baffle may be provided at the rear of the grate to slow the products of combustion and to cause them to follow a tortuous path.

[0011] The baffle may comprise a refractory wall depending downwardly from the roof of the furnace adajcent the exit therefrom.

[0012] A grit arrestor means may be provided, together with means to feed the arrested grit into'the furnace chamber to refire the grit.

[0013] The grit arrestor may be located at or adjacent the baffle.

[0014] Alternately, the grit arrestor means may be provided at any other suitable location, such as adjacent said means to remove the reduced temperature products of combustion from the heater.

[0015] The invention will now be described in more detail by way of example with reference to the accompanying drawing which is a diagrammatic cross-sectional view through an air heater embodying the invention.

[0016] Referring to the drawing, a shell is indicated generally at 10 and defines an air space 11. Mounted within the shell 10 is a furnace tube 12 having a grate 13 for solid fuel therein and a fuel feed tube 14 being provided which extends downwardly through the shell 10 and air space 11, and through the roof 12a of the furnace 12.

[0017] Means, 14a are provided within the tube 14 to feed solid fuel, fed to the top of the tube by screw/pneumatic feed means 14b-onto the grate 13. If desired the heater may be fired alternatively, or in addition, by gaseous or liquid fuel preferably by burner means provided on a door 15 at the front of the heater.

[0018] Primary air for combustion is fed to the underside of the grate 13 by suitable means through ducts 16 and further air for combustion is fed downwardly through the tube 14.

[0019] A refractory dam wall 17 is provided at the rear of the grate 13 and a refractory baffle wall 18 depends downwardly from the roof of the furnace chamber 12 to cause the products of combustion to follow a tortuous path indicated by the arrow A to reduce its velocity and thus to facilitate the arrest of grit by means of a suitable grit arresting means indicated at 19 provided with a venturi device 20 so that arrested grit is recirculated into the furnace chamber 12 and refired.

[0020] In the present example, a perforated steel plate 18a is provided between the lower end of the wall 18 and the wall of an exit duct 18b from the furnace chamber 12. The plate 18a serving to still further reduce the velocity of the products of combustion. If it is found that such further reduction in velocity is not required, the plate 18a can be omitted.

[0021] Downstream of the baffle wall 18 is a temperature reducing and gas diluting chamber 21 wherein the products of combustion are cooled and diluted as a result of introducing air into the interior of the chamber through openings 22 from the air space 11 to which air is fed through entry ducts 23 by a fan 23a. The air is thus heated by, and cools, the furnace chamber 12 before entry into the chamber 21.

[0022] The cooled and diluted products of combustion leaving the chamber 21 from an outlet 24 are then fed to the desired source of application.

[0023] If desired, the grit arrestor means 19 may be provided adjacent the outlet 24 from the chamber 21 or at any other desired location.

[0024] If desired the products of combustion may not be diluted in which case the cooling air would be extracted from the air space 11 and may be utilised as desired.

[0025] It will be appreciated that the heated gas provided by this heater comprises air and products of combustion and there are many applications in industry for such heated gas.

Claims

1. A gas heater characterised by the provision of a furnace (12), means (13, 14, 14a, 14b) for firing the furnace (12), means (13b) for feeding the products of combustion from the furnace (12) into a temperature reducing chamber (21) and means (24) to feed the reduced temperature products of combustion from the heater.

2. A gas heater according to Claim 1 wherein air is introduced into the temperature reducing chamber (21) to dilute and cool the products of combustion.

3. A gas heater according to Claim 1 or Claim 2 wherein the furnace (12) and temperature reducing chamber (21) are located within a shell (10), there being an air space (11) between the shell (10) and the furnace (12) and temperature reducing chamber (21) and means (23, 23a) for feeding cooling air through said space (11) to cool the furnace (12) and temperature reducing chamber (21).

4. A gas heater according to Claim 3 when dependant upon Claim 2 wherein said cooling air provides said air introduced into the temperature reducing chamber (21).

5. A gas heater according to any one of the preceding claims wherein the means (14, 14a, 14b) to fire the furnace comprises a grate (13) within the furnace and means (14, 14a, 14b) to feed solid fuel to the grate (13).

6. A gas heater according to Claim 5 wherein means (14,14a,14b) are provided to feed fuel downwardly through the shell (10) and air space (11) into the furnace (12) and onto the grate (13).

7. A gas heater according to Claim b wherein said means (14,14a,14b) comprise a fuel feed tube (14) extending downwardly through the shell (10), air space (11) and the roof (12a) of the furnace.

8. A gas heater according to Claim 7 wherein a solid fuel feed means (14a) is provided within the tube (14b) to feed fuel onto the grate (13).

9. A gas heater according to any one of Claims 5 to 8 wherein a grit arrestor means (20) is provided, together with means (20b) to feed the arrested grit into the furnace (12) to refire the grit.

10. A gas heater according to any one of the preceding claims wherein a baffle (18) is provided at the rear of the grate (13) to slow the products of combustion and to cause them to follow a tortuous path.

11. A gas heater according to Claim 10 wherein said baffle (18) comprises a refractory wall depending downwardly from the roof (17a) of the furnace (12) adjacent the exit (18b) therefrom.

12. A gas heater according to Claim 10 or Claim 11 when dependant upon Claim 9 wherein the grit arrestor means (20b) is located at or adjacent the baffle (18).

13. A gas heater according to any one of Claims 5 to 9 wherein the grit arrestor means (20) is provided adjacent said means (24) to feed the reduced temperature products of combustion from the heater.

Drawing