GB398493A - Improvements in forced draught furnaces - Google Patents

Abstract

398,493. Firegrates. BENNIS, A. W., Bennis Works, Highfield Road, Little Hulton, near Bolton. Feb. 5, 1932, No. 3424. [Class 51 (i).] Air supply, regulating. -In a forced-draught furnace in which the firebars are supported on longitudinally reciprocating troughs, each trough is divided by transverse partitions A<3> into compartments, vena-contracta nozzles supplying each compartment with air from a single chamber E, or from a number of chambers, in which air is maintained under pressure. The nozzles D are controlled by dampers D<1>, which may be actuated separately or together, for instance by being connected to levers operated by a drum with cam projections and laterally movable to operate different sets of dampers. The chamber E may be divided by longitudinal or transverse partitions, or both. Each nozzle may be fed from a single compartment. The nozzles D may as shown be fixed to the platform B which supports the trough A, or may be attached to and move with the troughs A, openings to enable this being provided in the platform B. The troughs may have side openings to supply air to the spaces between themselves. Openings A<2>, B<2> in the troughs and platform respectively are so disposed as to allow ash to fall through intermittently into hoppers F, provided with valves F<1>. The Provisional Specification describes a similar furnace in which the troughs are not subdivided. Such troughs may be fed by additional nozzles from an air chamber in front of the grate. It describes also an internally fired boiler, such as a Lancashire or Scotch marine type, in which an air-supply chamber is disposed at the front of the grate. Its lower wall is extended so as to form a platform on which the troughs rest. Vena-contracta nozzles are formed at the front of each trough. Air also passes from the chamber between the troughs. The base of each trough is open except for transverse bars, which during the motion of the bar expose openings in the supporting platform to discharge ash. Lateral extensions on the sides of the troughs may act similarly with respect to openings allowing the discharge of ash between the troughs. Specification 353,609 is referred to in the Provisional Specification.