Improvements in and relating to Low-pressure or Condensing Engines.
Year: 1890

page_text: Date of Application, 19th Apr., 1890
Complete Specification Left, 3rd Nov., 1890-Accepted, 6th Dec., 1890
TCATION
Improvements in and relating to Low-pressure or Condensing
Engines.
I, JOHN DARROCH of Springhill, Windsor Crescent, Newport in the County of
Monmouth, Engineer do hereby declare the nature of this invention to be as
follows:
This invention refers to improvements in and relating to low pressure or condensing
engines and has for its object to facilitate the working thereof by certain improve-
ments which I introduce in connection with the condensing or vacuum apparatus and
which I will now proceed to foreshadow.
Firstly I provide on or in connection with the overflow pipe or its equivalent of
the hot well a valve or valves communicating both with the atmosphere and with the
hot well and its communications so that the action of the valve or valves may
be more or less automatically controlled by the actions of the pump or pumps
feeding the boiler or boilers from the hot well on the one hand and drawing the
water and air from the condenser and supplying it to the hot well or its equivalent on
the other hand.
Secondly I arrange a pipe or connection between the working barrel of the air
pump and the chamber or space situate above or beyond the head-valves thereof and
on the pipe or connection so situate I place a cock or its equivalent to be by
preference hand actuated so that a direct communication can be established at will
between the parts aforesaid more or less independently of the action of the head
valves.
The effect of the above described apparatus is to increase the efficiency of the
pumps to assist in maintaining a vacuum and to relieve the working of the
engines.
A. CRAWHALL CHAPMAN,
3, St. Nicholas Buildings, Newcastle-on-Tyne, Patent Agent for Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Low-pressure or Condensing
Engines.
I, JOHN DARROCH of Springhill, Windsor Crescent, Newport in the County of
Monmouth, Engineer do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
This invention refers to improvements in and relating to low pressure or condensing
engines and has for its object to facilitate the working thereof by certain improve-
ments which I introduce in connection with the condensing or vacuum apparatus and
which I will now proceed to foreshadow.
Firstly I provide on or in connection with the overflow pipe or its equivalent of
the hot well a valve or valves communicating both with the atmosphere and with the
hot well and its communications so that the action of the valve or valves may be more
or less automatically controlled by the actions of the pump or pumps feeding the
boiler or boilers from the hot well on the one hand and drawing the water and air
from the condenser and supplying it to the hot well or its equivalent on the other
hand.
Secondly I arrange a pipe or connection between the working barrel of the air
pump and the chamber or space situate above or beyond the head valves thereof and

page_text: on the pipe or connection so situate I place a cock or its equivalent to be by
preference hand actuated so that a direct communication can be established at
will between the parts aforesaid more or less independently of the action of the head-
vaivus.
The effect of the above described apparatus is to increase the efficiency of the
pumps to assist in maintaining a vacuum and to relieve the working of the
cogines.
To fully explain my invention I will now refer to the accompanying drawings in
which Fig. 1 shows a sectional elevation of an air pump, hot well and feed plunger
pump, Fig. 2 being an half sectional elevation of the upper portion of Fig. I taken at
right angles to the view shown in Fig. 1 and throughout this description like marks
or letters of reference designate like parts.
Referring to the figs. A is an air pump barrel, B the bucket, C the hot well, D) the
overflow thereof, E the feed plunger pump and F the valves thereof all arranged in
the usual way. The parts or appliances in connection therewith which constitute my
invention are as follows, viz. the pipe or port G connecting the upper extremity of
the air pump barrel with the hot well and the valve H on or in connection with the
overflow pipe D of the hot well.
The object of this invention is to get rid to as great an extent as possible of air
which is readily absorbed by the water of condensation. The extent to which air and
air cushioning is known to damage pumps and connections and to "pit" the internal
surfaces of boilers though appreciated has been hitherto for the most part disregarded.
Let us now consider the action of the apparatus illustrated in the accompanying
drawings, firstly without the addition of the appliances constituting my improvements
and secondly with such addition. Firstly then at each upstroke of the air pump
bucket B a volume of water and air is discharged through the head valves J into the
hot well but in performing this operation the stratum of air lying between the surface
of the water overlying the bucket and the head valves aforesaid is more or less com-
pressed causing air cushioning and knocking of the engines. The water and air
thus discharged to the hot well may be then transferred by the pump E to the boilers
the displacement in the hot well being accompanied by a further inrush of air from
the atmosphere through the open end of the overflow pipe D. Now by the pipe or
port G and valve H, not only is the inrush of air aforesaid prevented on account of
the action of the downstroke of the air pump bucket automatically closing the
valve H, but on the upstroke the stratum of air overlying the water below the head-
valves finds free egress through the pipe or port G to the hot well and thence (under
the action of the upstroke of the air pump bucket) through the automatic valve H to
the atmosphere. Thus the air is excluded and the working of the feed pump and
engine rendered more regular. The water reaches the boilers in a more fit condition
for evaporation thus easing the firing and the gauge glasses are in like manner kept
cleaner.
The cock G on the port G is convenient for regulating the area thereof to meet
any special conditions of the engine. The port G may enter the hot well via G² G³
if desired.
The valve H may be an india rubber flap valve or a metal valve, the lift of the
latter being adjustable by means of set pins P and a cross bar P₁ as shown
in Fig. 3.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what 1
claim is:
1. In condensing engines connecting the upper end of the air pump barrel with
the hot well by means of a pipe or port G arranged adapted and operating
substantially as and for the purposes herein set forth.
2. In combination with an air pump and hot well, the arrangement or combination
of parts consisting of the pipe or port G and valve H on the overflow of the hot well
substantially as and for the purposes hereinbefore set forth.

page_text: 3. The arrangement or combination of parts constituting the improvements in low
pressure or condensing engines substantially as and for the purposes hereinbefore
set forth.
Dated this 30th day of October 1890
A. CRAWHALL CHAPMAN,
3, St. Nicholas' Buildings, Newcastle-on-Tyne, Patent Agent for Applicant.