IMPROVEMENTS IN THE MEANS AND APPARATUS FOR COMPRESSING AND FORCING AIR, WATER, AND OTHER FLUIDS
Year: 1876

page_text: LETTERS PATENT to Henry Davey, of Leeds, in the County of York, Engineer,
for the Invention of "IMPROVEMENTS IN THE MEANS AND APPARATUS
FOR COMPRESSING AND FORCING AIR, WATER, AND OTHER FLUIDS."
Sealed the 23rd September 1870, and dated the 22nd May 1876.
PROVISIONAL SPECIFICATION left by the said Henry Davey at the Office of
the Commissioners of Patents on the 22nd May 1876.
HENRY DAVEY, of Leeds, in the County of York, Engineer. "IMPROVEMENTS IN
THE MEANS AND APPARATUS FOR COMPRESSING AND FORCING AIR, WATER, AND
OTHER FLUIDS."
In direct-acting air compressing engines as at present employed there is a
considerable loss of useful effect, owing, among other things, to the necessity for using
the steam without expansion, the gradual increase of pressure in the air cylinder
during each stroke requiring that the pressure of the steam in the engine cylinder
should be at least maintained without reduction to the end of the stroke, or preferably
should increase during the stroke.
My Invention has reference to means for obviating this defect in air compressing
engines employed in mines and other localities where steam power is also required
for other purposes, such means being also applicable in engines for raising or forcing
water or other fluids. I supply the steam cylinder of the air compressing engine or
pumping engine with steam from a high-pressure boiler, and I cause the steam after
doing duty in the said engine to pass into a low-pressure boiler, the steam of which
is used for working the other machinery. Thus the steam acts in the said engine
with an effective pressure equal to the difference between the steam pressure in the
high-pressure boiler and that in the low-pressure boiler, and the whole of such steam
is at the end of the stroke made available for duty at a lower pressure without any
other loss than that due to radiation and, leakage. Furthermore I am enabled by
this method of working to throttle the supply of steam to an air compressing
engine at the beginning of the stroke, and to give a gradual increase of pressure
during the stroke, corresponding to the increase of pressure in the air cylinder,
without such loss of useful effect as would result from throttling the steam supply
in a similar manner in an ordinary high-pressure engine, in which case there
would be a loss equivalent to the difference between the quantity of steam
necessary when worked expansively to do the work and the full charge of high-
pressure steam contained in the cylinder at the end of the stroke.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Henry Davey in the Great Seal Patent Office on the 3rd November
1876.
HENRY DAVEY, of Leeds, in the County of York, Engineer.
"IMPROVEMENTS IN
THE MEANS AND APPARATUS FOR COMPRESSING AND FORCING AIR, WATER, AND
OTHER FLUIDS."
In direct-acting air compressing engines as at present employed there is a con-
siderable loss of useful effect, owing, among other things, to the necessity for using
the steain without expansion, the gradual increase of pressure in the air cylinder
during each stroke requiring that the pressure of the steam in the engine cylinder
should be at least maintained without reduction to the end of the stroke, or preferably
should increase during the stroke.
My Invention has reference to means for obviating this defect in air compressing
engines employed in mines and other localities where steam power is also required
for other purposes, such means being also applicable in engines for raising or forcing
water or other fluids. I supply the steam cylinder of the air compressing engine or
pumping engine with steam from a high-pressure boiler, and I cause the steain after
doing duty in the said engine to pass into a low-pressure boiler, the steam of which
is used for working the other machinery. Thus the steam acts in the said engine
with an effective pressure equal to the difference between the steam pressure in the
high-pressure boiler and that in the low-pressure boiler, and the whole of such steam
is at the end of the stroke made available for duty at a lower pressure without any
other loss than that due to radiation and leakage. Furthermore, I am enabled by
this method of working to throttle the supply of steam to an air compressing engine
at the beginning of the stroke, and to give a gradual increase of pressure during the
stroke, corresponding to the increase of pressure in the air cylinder, without such
loss of useful effect as would result from throttling the steam supply in a similar
manner in an ordinary high-pressure engine, in which case there would be a loss
equivalent to the difference between the quantity of steam necessary when worked
expansively to do the work and the full charge of high-pressure steam contained in
the cylinder at the end of the stroke.
Having thus described the nature of my Invention and in what manner the
same is to be performed, I hereby declare that I make no general claim to the use of
steam as in compound engines, wherein the steam is discharged from the high-
pressure cylinder into a reservoir or boiler, and passes thence to the low-pressure
cylinder, but I claim the method substantially as herein described of avoiding the
loss resulting from the use of steam without expansion in high-pressure direct-
acting air compressing or pumping engines by collecting the waste steam from
such engines in a low pressure boiler and drawing it thence, to work other
engines.
In witness whereof, I, the said Henry Davey, have hereunto set my hand and
seal, this Thirty-first day of October, in the year of our Lord One thousand
HENRY DAVEY. (L.S.)