Improvements in Machinery for Compressing Air and other Gases.
Year: 1892

page_text: Date of Application, 13th Sept., 1892
Complete Specification Left, 13th June, 1893—Accepted, 15th July, 1893
PROVISIONAL SPECIFICATION.
Improvements in Machinery for Compressing Air and other Gases.
I WILLIAM HENRY NORTHCOTT of Hatcham Ironworks, Pomeroy Street,
New Cross, London, Mechanical Engineer do hereby declare the nature of this
invention to be as follows:-
My improvements relate chiefly to certain details of construction, some of which
are applicable to the air and gas compressor described only whilst others are
applicable to gas compressors generally. The compressor referred to consists of
two single acting barrels in the same axial line. The first receives air from the
atmosphere direct and the second, formed in one with the piston of the first
cylinder, is smaller than the first from which it receives its air or gas. The second
& smaller cylinder delivers into a coil of pipe placed in any convenient chamber
through which water is circulated and thence off to a separating vessel or reservoir.
The large piston is packed by means of two leather strips, one to keep air from
passing from the large cylinder to the water chamber and the other to prevent
water passing the other way. Both cylinders are enclosed in a water casing
through which water is constantly circulated by the differential displacement of
the air pistons or otherwise, and the cooling coil may be placed in the water casing
or in a separate vessel located anywhere between the compressor and reservoir.
The small piston is packed with leather washers or a shallow cup with a washer
underneath it, and this style of packing is applicable also to other sliding joints,
although in certain cases asbestos cloth or other flexible material that will stand
heat is used instead of leather.
I prefer to make the main water casing separate from the lower cover of the
compressor and put the latter ou by a flanged joint, by breaking which and removing
the casing the internal parts are exposed for inspection. I drain the injection
water from the compressed air by means of a small pump drawing from the bottom
of the separating vessel or reservoir, or by means of valves opened and shut
periodically by cams or other means--such pump, cams or other appliances being
preferably actuated by the compressing engine itself.
Dated this 10th der of Sentember 1800
COMPLETE SPECIFICATION.
Improvements in Machinery for Compressing Air and other Gases.
I, WILLIAM HENRY NORTHCOTT, Hatcham Ironworks, Pomeroy Street, New
Cross, London, 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 :-
My improvements relate chiefly to certain details of construction, some of which
are applicable to the air and gas compressor described only, whilst others are
applicable to gas compressors generally. The compressor referred to consists of
two single acting barrels in the same axial line. The first receives air from the
atmosphere direct, and the second, formed in one with the piston of the first
cylinder, is smaller than the first from which it receives its air or gas. The second
and smaller cylinder delivers into a coil of pipe placed in any convenient chamber
through which water is oirculated and thence off to a separating vessel or reservoir.
The large piston is packed by means of two leather strips, one to keep air from
passing from the large cylinder to the water chamber, and the other to prevent
D

page_text: water passing the other way. Both cylinders are enclosed in a water casing
through which water is constantly circulated by the differential displacement of
the air pistons or otherwise, and the cooling coil may be placed in the water
casing or in a separate vessel located anywhere between the compressor and
reservoir. The small piston is packed with leather washers or a shallow cup
with a washer underneath it, and this style of packing is applicable also to other
sliding joints although in certain cases asbestos cloth or other flexible material
that will stand heat is used instead of leather.
I prefer to make the main water casing separate from the lower cover of the
compressor and put the latter on by a flanged joint, by breaking which and
removing the casing the internal parts are exposed for inspection.
I drain the injection water from the compressed air by means of a small pump
drawing from the bottom of the separating vessel or reservoir, or by means of
valves opened and shut periodically by cams or other means-such pump, cams or
other appliances being preferably actuated by the compressing engine itself.
In Figs. 1, 2 & 3, A & B are the two single acting barrels in the same axial
line, C. is the cooling coil round which water is circulated & through which the
compressed air is delivered. D & E are the two leather rings for the large piston,
the former for keeping the air in the large cylinder, & the latter for keeping water
out of it. They each have metallic spring rings behind them and they are pressed
outwards, D by air & E. by water pressure introduced by small holes connecting
with the air and water spaces respectively. G. is the water casing through which
the water is circulated by the plunger F. The packing for the small piston H.
shewn enlarged at Fig. 4 consists of one or more leather washers cut by preference
slightly larger than the small cylinder and kept in place by a nut smaller in
diameter than the washers by about twice the thickness of the leathers. This
reduced diameter however need not extend the full depth of the nut about a quarter
of an inch being sufficient. For piston rod packings, I form the packing as shewn
at Fig. 5, of a series of washers of leather or asbestos or other flexible material
and cut to fit the rod and the stuffing box. Between each leather washer, I place
a metallic washer, one fitting the rod but being loose in the stuffing box, and the
next fitting the stuffing box but being loose on the rod. The left-hand side of
Fig. 5 shews the packing as inserted, the right hand side shews the shape it becomes
after working.
The water casings are shewn bolted to the lower covers at I, and by breaking
this joint the casing may be removed and all the internal parts are then exposed.
Fig. 1. is a two stage, and Fig. 2. a three stage compressor and in both cases the
cooling coils are placed in the water casing.
Fig. 3. is a two stage compressor and the coil is here shown in a separate
vessel.
In
Figs. 6, 7 & 8, shew different plans for continually draining the separator
columns. In Fig. 6. a small pump has its suction A. connected to the drain of the
separator vessel so that the drain water admitted at A is forced out under a delivery
valve loaded at the full pressure of the reservoir and off by the pipe B.
Fig. 7 A. is the drain water inlet and B. its outlet pipe. The two valves C. & D
are alternately opened by the action of the rocking lever E. actuated by a crank
pin F. or otherwise. The quantity of water released may be regulated by altering
the lift of the valves or one of them, or by throttling the outlet at G. Instead of
the apparatus shewn at Figs. 6 & 7, I sometimes drain the separators_continually
by means of two or more throttling cocks placed on the drain pipe and preferably
with an air vessel on each, or on the last one, as shewn at Fig. 8. It is impractic-
able to get a steady drain by means of one throttling valve, but by dividing the
difference of pressure between the reservoir and the atmosphere amongst two or
three valves, a steady drain off may be obtained. The drain water, if used
again, is passed through a filter or strainer placed between the drain valves or
elsewhere.

page_text: Having now particularly described & ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In machines for compressing air & other gases as herein before described
the method of so arranging the pumps & water casing that the whole may be
easily taken apart substantially as described & illustrated in the accompanying
drawings.
2. In the compressors described, the method of connecting the cooling coil to the
compressor outlet substantially as shewn in the accompanying drawings.
3. The intermediate valve for compressors, substantially as shewn in the
accompanying drawings.
4. The mechanism for draining the separators and receivers substantially as
described & shewn in the accompanying drawings.
5. The methods of packing the plungers and stuffing boxes substantially as
described & illustrated in the drawings.
6. The combination & arrangement of parts forming machines for compressing
air and other gases substantially as hereinbefore described and illustrated in the
accompanying drawings.
Dated this 12th day of June 1893.
WM. HY. NORTHCOTT.