IMPROVED CONSTRUCTION OF UNDERNEATH FIRED HORIZONTAL BOILERS
Year: 1883

page_text: "
PROVISIONAL SPECIFICATION left by Peter Jensen at the Office of the
Commissioners of Patents on the 28th March 1883. Communicated to him
from abroad by Wilhelm Tesch of Stockholm Sweden Machinery Agent.
PETER JENSEN of 33 Chancery Lane in the County of Middlesex " IMPROVED
CONSTRUCTION OF UNDERNEATH FIRED HORIZONTAL BOILERS (A Communication
to me from abroad by Wilhelm Tesch of Stockholin Sweden, Machinery Agent)
Hitherto such boilers have had an arch of brickwork built in front of their lower
part above the fireplace for the purpose of separating the fireplace from the flues
above. This brick work is generally of very short duration and constantly
requiring repairs especially when, as often is the case, a blow off pipe is projecting
through it, affected as it is by the strong heat coming from the fuel and by the
changing temperature and the consequent contraction and expansion of the boiler.
The present improved construction of the boiler tends to do away with all brick-
work over the fireplace.
This construction is especially applicable to the so called horizontal return tube
boiler and consists of the underpart of the boiler that lies between the lowest row
of tubes and the bottom, being extended beyond the boilers' front in the form of a
chamber which is properly stayed inside and is so wide that it entirely covers the
front part of the fire place or dead plate. The front of this chamber through
which the lower part of the boiler is to be cleaned, is closed in the usual manner
by a lid screwed firmly on and upon which the blow off cock can be placed.
The upper part of this extension chamber may be straight or curved which latter
arrangement should be chosen for boilers intended to work by high steam pressure.
The advantages of this boiler construction are.
1. That all repairs of the said brickwork arch are done away with, so that if the
boilers are set carefully, no repairs of the brickwork should be required for a
number of years.
2. That the interior bottom part of the boiler and the whole set of tubes can be
got at for the purpose of inspecting and cleaning.
3. That the firebars can be placed closer to the boiler.
4. That the direct heating surface, or that one directly exposed to the heat from
the coals and which of course is the most effective becomes larger.
It has been a rule especially in England to use inside fireplaces even for

page_text: stationary boilers set in brick work notwithstanding the impossibility of attaining
in such fireplaces a good combustion of the coals and although boilers thus con-
structed of necessity must be larger and therefore more expensive. Why it has
been so arises, no doubt upon the indurability of the brick arch above the fireplace
and the height of the fireplace required for boilers, to be fired from below both of
which inconveniences have been considered inseparable from such boilers as long as
it has been a question of single (not coupled) boilers. By the new arrangement
here described the reason for choosing boilers with inside fireplaces are entirely
removed so that in reference to boilers to be immured set in brickwork hardly any
but those with underlying fireplaces should be found acceptable, because only these
latter ones allow a correct construction of the fireplace capable of a complete and
economical combustion of the coals without unnecessary surplus of heated air. The
saving of fuel hereby gained can easily be fully ascertained by comparative trials of
the one and other kind of boilers.