Improvements in Apparatus for Delivering Measured Quantities of Liquid.
Year: 1890

page_text: Date of Application, 8th Oct., 1890
Complete Specification Left, 8th July, 1891-Accepted, 8th Aug., 1891
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Delivering Measured Quantities
of Liquid.
I, ARTHUR JAMES POSTANS, of 30 Museum Street, in the County of Middlesex,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to that class of apparatus in which liquid is admitted into
and drawn out of a measuring chamber by a two way cock.
The present apparatus has two co-axial cylinders of different diameters placed
end to end and with a common plunger or piston. The small cylinder is always in
connection with the supply pipe. The large cylinder can be connected either to
the supply pipe or to the delivery pipe by a two way cock.
The action of the apparatus is as follows:-
When both cylinders are open to the supply the piston by reason of its greater
area in the large cylinder is forced to the supply end of the small cylinder allowing
the large cylinder to fill. When the two way cock is turned so as to cut off the
large cylinder from the supply and open it to the delivery pipe the pressure on
the larger area of the piston is relieved and the pressure of the supply on its smaller
area then forces it into the large cylinder expelling the liquid through the
delivery pipe.
I do not employ stuffing boxes to make air tight joints between the piston and
cylinders but as has before been proposed I connect one end of a flexible tube to
the piston and the other end to the cylinder. In place however of making the
attachments in such a way as to cause the tube to crease or fold as its ends approach
each other I turn the tube back upon itself so that as the piston moves the length
of tube which is turned back varies but the inside and outside portions of the tube
both remain cylindrical without creases.
The tubes are placed as heretofore in the annular spaces between the outside of
the pistons and the inside of fixed casings.
When it is desired to vary the quantity of liquid delivered I limit the travel of
the piston in any of the ordinary and well known ways.
Dated this 7th day of October 1890.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Delivering Measured Quantities
of Liquid.
I, ARTHUR JAMES POSTANS, of 30 Museum Street, in the County of Middlesex,
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 relates to that class of apparatus in which liquid is admitted into
and drawn out of a measuring chamber by a two way cock.
The present apparatus has two co-axial cylinders of different diameters placed
end to end and with a common plunger or piston. The small cylinder is always in
connection with the supply pipe. The large cylinder can be connected either to
the supply pipe or to the delivery pipe by a two way cock.

page_text: The action of the apparatus is as follows:-
When both cylinders are open to the supply the piston by reason of its greater
area in the large cylinder is forced to the supply end of the small cylinder allowing
the large cylinder to fill. When the two way cock is turned so as to cut off the large
cylinder from the supply and open it to the delivery pipe the pressure on the larger
area of the piston is relieved and the pressure of the supply on its smaller area then
forces it into the large cylinder expelling the liquid through the delivery pipe.
I do not employ stuffing boxes to make air tight joints between the piston and
cylinders but as has before been proposed I connect one end of a flexible tube to
the piston and the other end to the cylinder. In place however of making the
attachments in such a way as to cause the tube to crease or fold as its ends
approach each other I turn the tube back upon itself so that as the piston moves
the length of tube which is turned back varies but the inside and outside portions
of the tube both remain cylindrical without creases.
The tubes are placed as heretofore in the annular spaces between the outside of
the pistons and the inside of fixed casings.
When it is desired to vary the quantity of liquid delivered I limit the travel of
the piston in any of the ordinary and well known ways.
In order that my said invention may be more fully understood and readily carried
into effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figures 1 and 2 are sections of an apparatus constructed according..to my
invention.
In Figure 1 both cylinders are open to the supply and the piston has been forced
into the smaller, whilst in Figure 2 the smaller cylinder only is open to the supply
and the piston has been forced into the larger.
A is the large cylinder and B the small cylinder. a a is the portion of the
plunger or piston having the larger diameter and is the portion having
the smaller diameter. C is an outer casing which forms a continuation of the
cylinder A, and D is an inner casing which forms a continuation of the cylinder B,
but in each case there is a small space left between the casing and the outside of
the end of the cylinder to receive the end of the india rubber tube which forms an
air tight joint between the cylinder and the piston. There are two of these
tubes E and F. One end of the tube E is secured to the end of the cylinder,A by
a binding e of thread or wire, preferably this joint is covered by a band G. of india
rubber which presses the tube E against the plunger and assists. in expelling the
last portion of liquid from the cylinder A. The other end of the tube E is secured
by a binding to the portion a of the plunger. Preferably the lower part a' of
this is screwed on as shown, the binding being enclosed in a space between the
two parts a a', the india rubber being also further secured by being nipped between
them. One end of the tube F is similarly secured by a binding and screw joint
between the portions of the piston or plunger, whilst, the other endeis, secured
by a binding to the smaller cylinder B.
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 I
claim is :-
1. Apparatus for delivering measured quantities of liquid consisting of two
co-axial cylinders having a common piston or plunger, the smaller cylinder,,being
always open to the supply and the larger cylinder being connected by a two-way
cock alternately to the supply and delivery substantially as described.
2. In apparatus for delivering measured quantities of liquid making an air-tight
joint between the cylinder and the piston or plunger by means, of a flexible tube

page_text: turned back upon itself and having its ends connected to them respectively sub-
stantially as described.
3. Apparatus for delivering measured quantities of liquid substantially as
described and shown in the drawings.
Dad Local of T. 1901