US2336339A - Water tube wall of steam generator furnaces - Google Patents

Description

Fig.2.

//v VEA/Tw? A Z fred W'eizizzb" ATTORNEYS A. W. BENNIS Dec. 7, 1943;

WATER TUBE WALLS OF STEAM ('S'IEINERA'IIFOR FURNACES Filed Dec. 12, 1941 n n III x U n u G G I I n m I.IHHH W Hm 1 m m n D m I I FII I IIIIIIIIIIIIIIIII IILH D u u I C C x- IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII I II+. n "15 -I U u w B i I B B 2 m wu I l I l l l l l l l l I l l |.||l lllll lllllllllUn m n f5 1f-. D u u m c c h." m Um I I m L n I m m. I w lllll Patented Dec. 7, 1943 lJNlTED STAT WATER TUBE WALL F STEAM GENERATOR FURNACES 7 Alfred William Bennis, Little Hulton, Bolton, England 1 Claim.

This invention relates to improvements in the water tube walls of steam generator furnaces. In furnaces of this kind it had previously been proposed to provide, on all the tubes, diametrically opposed fins disposed in the same plane with only sufiicient space between the adjacent edges of the fins to permit of the expansion thereof from the heat of the furnace. The advantage of this arrangement is that practically the whole surface of the wall is comprised of metal which is exposed to the radiant heat of the furnace. With this arrangement however the tubes have to be spaced some distance apart to accommodate the fins disposed on either side of the tubes and adversely eifects the surface area of the wall actually in contact with the water. Furthermore the additional space between the tubes necessitates the provision in the headers of a hand hole to serve each tube.

It has also been proposed to increase the tubular heating surface of the wall by increasing the number of tubes by dividing them into two groups and using separate headers to feed each group. With this arrangement however, it not only entails the provision of two headers to feed the tubes but the bending of the tubes of at least one group, where they leave the headers in order to bring them into the same plane as the other group, which is not considered good practice and increases the cost of production.

The object of the present invention is to retain the advantage of the fin tube construction previously described whilst at the same time increasing the surface area of the wall in contact with the water and reducing the cost of production and upkeep by reducing the number of small parts.

According to this invention a water tube wall for a steam generator furnace is comprised of tubes having diametrically opposed fins alternating with plain tubes. The fins preferably extend across the space between the tubes, sufficient space only being left between the outer edges of the fins and the adjacent tubes to permit of the expansion of the fins. A further feature of the invention is the provision of hand holes adapted to serve two tubes so that the number of small parts is reduced.

The invention will now be more particularly described with reference to the accompanying drawing in which: v

Fig. 1 is a front elevation,

Fig. 2 is a sectional side elevation and Fig. 3 a sectional plan of a part of a water tube wall constructed according to our invention.

Like letters indicate like parts throughout the drawing.

In carrying out this invention the ends of the tubes forming the wall are connected in the usual manner to headers A and alternate tubes B in the wall are provided with diametrically opposed fins B B which are preferably disposed in the same plane as the axes of the tubes and extend substantially the full length of the tubes. The remaining tubes C are plain tubes and are disposed so that there is only sufficient space between the surface of the plain tubes C and the outer edges of the fins B B disposed on either side thereof to permit of the expansion of the fins. With this arrangement the tubes can be disposed much closer together than in the arrangement previously described in which fins are provided on all the tubes, whilst at the same time providing ample strength between the holes formed in the headers A to receive the tubes. With the tubes being close together the hand holes D provided in the headers for serving the tubes can be adapted to serve two tubes so that the number of hand holes required is reduced. As each hand hole has to be provided with suitable closing means the reduction in the number of hand holes effects a corresponding reduction in the cost of production and upkeep owing to the reduction in the number of small parts.

With the arrangement described the advantage of the fin tube construction is obtained as practically the whole of the surface of the wall exposed to the radiant heat of the furnace is metal. The tubes are closer together and thus provide an increased heating surface whilst at the same time providing an increased water cooling surface which has a tendency to lower the temperature of the furnace and permit the use of a higher CO2 content therein. Furthermore the increased cooling surface permits of a greater transfer of heat to the water with a consequent increase in the efiiciency of the furnace and the cost of production is reduced as only half the tubes are provided with fins and the number of hand holes for serving the tubes is also reduced.

What I claim as my invention is:

A water tube wall for a steam generator furnace comprised of headers interconnected by tubes with adjacent tubes extending essentially parallel toone another, said tubes consisting alternately of tubes having fins and of plain tubes, the tube fins each extending in generally radial direction from each finned tube toward the center of the adjacent plain tube with only sufficient space being left between the outer edge of each fin and the wall of the adjacent plain tube to permit of the expansion of the fins and with each fin extending substantially the full length of its corresponding tube between the headers.

ALFRED WILLIAM BENNIS.

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