IMPROVEMENTS IN SCREW FANS
Year: 1886

page_text: Date of Application, 5th May, 1886.
Complete Left, 5th Mar., 1887.
Complete Accepted, 3rd May, 1887.
I CHARLES SPRUYT DE BAY Civil Engineer A.I.C.E. of 52 Westbourne Park Road
Westbourne Park London W. do hereby declare the nature of my invention for
IMPROVEMENTS IN SCREW FANS to be as follows:-
This improvement consists in placing two or more complete sets of blades, that is
two or more complete fans, separated from one another by a short distance. In the
case of the fan for which I obtained a patent granted to me A.D. 1877-21st of March
No. 1126; two complete fans, each made up of two interlacing screws; will always
give any amount of water guage, which may practically be wished for, but in the case
of the ordinary screw fans a greater number may be used, when it would be advan-
tageous to give by means of a hollow shaft surrounding the solid shaft, a rotary
direction to one or some of the fans contrary to that given to the others. All the fans
should be contained in the same drift or casing and an envelope connecting the bosses
should be placed round the shafting to prevent the air getting in the spaces between
the bosses.
The outside fan may be made of larger diameter or of a longer pitch than the
inside one, or both the increased diameter and the increased pitch may be used
together.
Dated this 4th day of May 1886.
CHARLES SPRUYT DE BAY.
Improvements in Screw Fans.
We CHARLES SPRUIT DE BAY formerly of 52 Westbourne Park Road W. but now
of 7 Old Hall Street Hanley in the County of Stafford Civil Engineer Associate of the
Institute of Civil Engineers and WILLIAM JORN MOXON of Hanley in the said County
of Stafford Gentleman do hereby declare the nature of this invention for IMPROVE-
MENTS IN SCREW FANS and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
On the same shafting we place two or more complete fans separated from one

page_text: another by a short distance. When the fan is of the kind for which one of us namely
the said Charles Spruyt de Bay obtained a patent numbered 11.26 and dated 21st of
March A.D. 1877 and another patent for improvements numbered 10989 and dated
6th of August 1884 each made of two or more interlacing screws then two such fans
will always be sufficient, but in the case of ordinary screw fans a greater number may
be used when found desirable it will then be advantageous to give a contrary curve
and contrary rotary direction to one or some of the fans to the curve and rotary
direction of the other fan or fans by means of one or several hollow shafts surrounding
the solid shaft all the fans should be placed in the same drift or casing and a cylindrical
envelope should be placed outside the shafting to prevent the air gotting in the space
between the bosses.
The outside fan may be made of larger diameter or of a longer pitch than the
inside one or both increase of diameter and increase of pitch may be used together.
When this improvement is used for fans for which the before mentioned patents
have been obtained the blades of the screws will be the same in their outlines for both
fans but whereas in one of the fans the big blade will be on the entering side and the
small blade on the leaving side of the fan their position must be reversed on the other
fan and for this reason the side of the blade which is the face of it in one fan will have
to be the back in the other fan.
When driven by belts an aperture will be wanted in the drift or casing for one of
the belts to pass through We will then use rollers guiding the belt a pair of rollers
for the lower half of the belt and another pair for the upper part of it and stop the
space between the two pairs of rollers and the bottom of the aperture and also between
the upper pair of rollers and the top of the aperture.
Having now particularly described and ascertained the nature of the invention of
both or one of us and in what manner the same is to be performed we declare that
what we claim is
1. The use of two or several screw fans working in the same drift or casing and all
on the same shafting which would be used for one fan only except that in the case of
ordinary non interlacing screw fans we may use a hollow shaft in the same way as
used in the said Charles Spruyt de Bays fan in order that a rotary direction may be
given to one or some of the ordinary screw fans contrary to that given to the other
fan or fans.
Dated this Third day of March 1887