VERTICAL TUBE WATER HEATER

Abstract: A vertical tube water heater comprising a water tank (22) within which are located a plurality of tubes (25) and a vertical combustion tube (26) provided at its upper end with a burner (29), the bottom ends of said tubes (25) and combustion tube (26) being in communication with a chamber (28) located at the bottom of the tank (22) and the upper ends of the tubes (25) being in communication with a header chamber (27) located at the upper end of the tank (22) and which is in communication with an exhaust duct (32,33), the arrangement being such that when the water heater is operating at low temperature settings any condensation formed within the tubes (25,26) is evaporated or drained and can not reach the burner (29) to extinguish it or its pilot light.

Description: This invention relates to a vertical tube water heater. A vertical tube water heater is known from GB-A-2 145 803 which comprises a water tank, a plurality of vertical tubes located within the tank, one end of each of the tubes being in communication with a combustion chamber located at the bottom of the tank and in which are provided burners, and the other end of each tube is in communication with a chamber located at the upper end of the tank and which is in communication with an exhaust duct. When such a known water heater is operated at low temperature settings, condensation is produced in the vertical tubes and the condensate falls by gravity into the combustion chamber and can extinguish the pilot light of the burner or even the burner itself. Therefore such vertical tube water heaters can not be operated at low temperature settings. A water heater having the features recited in the pre-characterising part of appended claim 1 is known from AT-B-221 258. In this known water heater the combustion chamber is supplied with secondary air for supporting combustion and at low temperature settings the combustion chamber will receive condensate which will accumulate and can reach a level in which it prevents secondary air flowing into the combustion chamber and no means are provided for removing the condensate at low temperature operation. The present invention aims to provide a water heater in which condensate is removed at all conditions of operation thus enabling the water heater to be operated at low temperature settings. According to the present invention there is provided a vertical tube water heater comprising a water tank, a plurality of vertical tubes located within the tank, one end of each of the tubes being in communication with a first chamber located at the bottom of the tank for receiving hot gases from a burner and the other end of each of said tubes being in communication with a second chamber located at the upper end of the tank, the second chamber being in communication with an exhaust duct, and located within the tank a vertical combustion tube which at its upper end is provided with said burner and at its bottom end is in communication with said first chamber, characterised in that the second chamber is in communication with said exhaust duct via a third chamber located beneath said first chamber and said exhaust duct is provided with a fan for drawing air through the water heater to the burner, for withdrawing gases from the second chamber and third chamber, and for withdrawing condensate from the first and third chambers. An embodiment of the invention will now be described, by way of an example, with reference to the accompanying drawings, in which:- Figure 1 is a vertical longitudinal section through a water heater embodying the present invention; and Figure 2 is a fragmentary side view taken in the direction of the arrow 2 indicated in Figure 1 showing the vanes in the ducts. The water heater shown in Figure 1 comprises a water tank 22 having an upper end wall 23 and a lower end wall 24 and a plurality of vertical tubes 25 which extend through the ends walls 23 and 24. Also extending vertically through the end walls 23 and 24 is a central vertical combustion tube 26. The tank 22 is circular and the vertical combustion tube 26 is located on the axis of the tank 22. The tubes 25 are disposed in a circular array around the combustion tube 26. A header chamber 27 is provided at the upper end of the tank 22 and through which the combustion tube 26 extends. At the bottom of the tank 22 is provided a chamber 28. The tubes 25 communicate with the header chamber 27 and the tubes 25 and the combustion tube 26 all communicate with the chamber 28. At its upper end the central combustion tube 26 is provided with a gas or oil burner 29 located within a short perforated tube 30 connected to the combustion tube 26. Located beneath the chamber 28 is a chamber 31 which is in communication with the header chamber 27 via an annular duct 32 surrounding the tank 22. Located in the duct 32 are a plurality of vanes 32 a (Figure 2) which are attached to the radially inner wall of the duct 32 and which cause the exhaust gases to swirl around the duct 32 as the gases flow downwardly through the duct 32 and the vanes 32 a convey heat to the inner wall of the duct 32. The chamber 31 is provided with an exhaust duct 33 connected to a fan 34 which is preferably driven by an electric motor. The fan 34 can be located at the downstream end of an exhaust duct 33 and thus located at a position remote from the water heater. The exhaust duct 33 may be of small diameter compared with conventional water heaters which require a large flue with negative flue draught. Thus, the fan 34 can be located at either end of the exhaust duct 33. Surrounding the tank 22 is a further annular duct 35 for conveying air from beneath the bottom of the water heater to an air chamber 36 located above the tank 22 and through which the perforated tube 30 extends, the air flowing from the chamber 36 through the perforations in the tube 30 to the to the burner 29. Located in the duct 35 are a plurality of vanes 35 a (Figure 2) which are attached to the radially inner wall of the duct 35 and which cause the air to swirl around the duct 35 as it flows upwardly through the duct 35 and the vanes 35 a transfer heat to the air from the inner wall. The fan 34 draws air through the duct 35 and chamber 36 and draws the combustion gases from the header chamber 27 through the duct 32, chamber 31 and exhaust duct 33 and discharges the exhaust gases to atmosphere. The tank 22 is provided with a transverse plate 37 which prevents scale falling into the lower wall 24. When the water heater is operating at low temperature settings which produces condensation in the tubes 25 and 26 any condensate which falls onto the bottom of the chamber 28 is evaporated or if the bottom of the chamber 28 is too cool to effect evaporation, the condensate is drawn out by the fan 34. When operating at lower temperature settings any condensate can not reach the burner 29 and therefore can not extinguish the burner. Such a water heater may be used for heating sea water which is pumped into divers suits to heat them.

Claims: A vertical tube water heater comprising a water tank (22), a plurality of vertical tubes (25) located within the tank (22), one end of each of the tubes (25) being in communication with a first chamber (28) located at the bottom of the tank (22) for receiving hot gases from a burner (29) and the other end of each of said tubes (25) being in communication with a second chamber (27) located at the upper end of the tank (22), the second chamber (27) being in communication with an exhaust duct (33), and located within the tank (22) a vertical combustion tube (26) which at its upper end is provided with said burner (29) and at its bottom end is in communication with said first chamber (28), characterised in that the second chamber (27) is in communication with said exhaust duct (33) via a third chamber (31) located beneath said first chamber (28) and said exhaust duct (33) is provided with a fan (34) for drawing air through the water heater to the burner (29), for withdrawing gases from the second chamber (27) and third chamber (31), and for withdrawing condensate from the first and third chambers (28, 31). A vertical tube water heater as claimed in claim 1, in which the vertical combustion tube (26) extends within the second chamber (27). A vertical tube water heater as claimed in claim 1 or claim 2, in which said tank (22) is circular and the vertical combustion tube (26) is located on the axis of said tank (22), said plurality of tubes (25) being disposed in a circular array around the vertical combustion tube (26). A vertical tube water heater as claimed in any preceding claim, in which a transverse plate (37) is provided in the tank (22) to prevent scale falling onto the bottom wall (24) of the tank (22). A vertical tube water heater as claimed in any preceding claim, in which the second chamber (27) is in communication with said third chamber (31) via an annular duct (32) surrounding the tank (22). A vertical tube water heater as claimed in any preceding claim, in which an annular air duct (35) surrounds the tank (22) for conveying combustion air from beneath the bottom of the tank (22) to an air chamber (36) located above the tank (22), said air chamber (36) being in communication with said burner (29). A vertical tube water heater as claimed in claim 5 or claim 6, in which the annular duct (33) and the annular air duct (35) are each provided with vanes (32 a , 35 a ) which extend within the respective duct. A vertical tube water heater as claimed in any preceding claim, in which the burner (29) is located within a perforated tube (30) connected to the upper end of the burner tube (26) and extending through said air chamber (36).

Inventors: MATON, MAURICE EDWARD GEORGE
Applicants: BEAUMONT(U.K.) LIMITED
Application year: 1987
Main classification: F24H1
IPC codes: F24H1