Improvements in Machinery or Apparatus for Producing Pressure, or a Varied Degree of Vacuum.
Year: 1886

page_text: Improvements in Machinery or Apparatus for Producing
Pressure, or a Varied Degree of Vacuum.
I JOHN WILLIAM HOLLAND of 23 Sparshólt Road Upper Holloway 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:—
My improvements are intended to provide a better, more simple and more
effective apparatus, than that described in the Specification of letters patent
No 2139 A D 1884 of which I am now the registered proprietor, for testing
pressure and vacuum. gauges to either high or low pressures, and which may be
employed also for proving steam boilers, and other vessels, boiler fittings and the
like which are intended to stand a high internal, or external pressure. The
apparatus consists of a cast cylinder of a suitable diameter having three or four or
other convenient number of nozzles fitted thereon or the casting inay be so formed
as to constitute two parallel cylinders of the same or different diameters and com-
municating with each other at or near one end, two or more of the nozzles being
fitted to the cylinder of the smaller diameter and one or more to the larger
cylinder. The apparatus may also have an independent tube attached either at
one end of the plunger tube, hereinafter particularly described, or parallel with the
plunger tube.
For very high pressures the apparatus may be formed in either of the modes
above described or I may form, in the casting three cylinders which may or may
not be of equal diameter, In all cases where I employ more than one cylinder
I prefer that one of them shall be of greater diameter than either of the others, or,
other. One of the cylinders, preferably the larger one, is bored out truly for the
passing to and fro of a plunger fitted watertight therein, through an annular guide
at one end of the cylinder. The plunger consists of a tube closed at one end
having a cup leather, or other liquid tight packing, secured to the closed end which
slides within the cylinder and at the opposite end an internal screw is formed to
enable the plunger to be operated by means of a screw and hand wheel. The screw
and hand wheel are centred in a line with the axis of the bored cylinder and are
supported in a bearing or carriage, which allows the screw and wheel a rotary
motion only. The wheel, being held rigidly to the screw by a key or other means:

page_text: The screw works in the internal screw in the plunger and on turning-the-hand--
wheel the screw is rotated and thereby the plunger is made to travel over the
screw in either a backward or forward direction. I enclose the screw in a barrel
or tube to protect it from injury and dirt, and at the end next the cylinder is an
annular guide through which the plunger passes, and at the opposite end I make
the bearing for the screw and hand wheel. The plunger and screw are so pro-
portioned that when the plunger is at the extremity of its outward travel the
screw is not. withdrawn from the screwed end thereof. The screw may be either
right handed or left handed.
I sometimes employ two plungers in one apparatus They may be arranged to
work in either of the cylinders but I prefer to place them in cylinders of larger
diameter than the cylinder or cylinders to which the nozzles are fitted.
In order that my invention may be better understood I have attached hereto
two sheets of drawings in which Figure 1 is a sectional elevation of a complete
apparatus with two parallel cylinders and Figure 2 is a cross section on the
line X X. A. A. is the larger cylinder. B B is the smaller cylinder. CC are the
nozzles cast or fitted thereon. D D are the nuts for connecting gauges thereto.
E is a globular vessel watertight below and at the diaphragm el. el is a corru-
gated metal diaphragm plate. e 2 is a plunger rod actuated by the rising of
diaphragm plate. e 3. e3 lever and weight acting upon the principle of the
steelyard. This globular vessel and diaphragm with lever and weight forms the
standard by which the gauges, vessels, fittings or the like are tested. 2 E shows
gauge to be tested. F is valve for charging and discharging apparatus. G is the
plunger. His packing and leather on end of plunger. I. I. is screw shaft. K K' is
carriage for screw shaft and plunger. L L are bearing nuts or guides for plunger.
M is solid or fast collar on shaft. N is recess for collar on, shaft formed in one end
of carriage. O is a cap screwed on the carriage K K₁ securing collar in the recess N
thus allowing the screw to revolve but preventing a inovement in either a back-
ward or forward direction. P is a wheel, or handle, or its equivalent, for actuating
screw shaft. Qis a bed plate to which the apparatus is secured, the whole being
mounted upon a wood block R. S is bib or spout of valve F, when the apparatus
is required for testing boilers, or other vessels, I fit or make this bib with union
for purposes of connection. T in figure 2 is a valve for shutting off cylinder A
from cylinder B and is so constructed that it can, if required, be used as a second,
or third, or auxiliary cylinder and plunger. For example when using the apparatus
to produce pressure, after the plunger G has reached the limit of its travel, the
plunger in the valve T may be operated to increase the pressure.
It is not essential that my improved apparatus be used only with the diaphragm
and steelyard arrangement shewn at E. 1. e 2. and c 3: but an ordinary standard
gauge may be used as shewn at Figure 3, U 1 being the standard gauge and U2
the gauge to be tested; or vice versa.
'
It may be here stated that the action of the apparatus is precisely the same.
whether used with the diaphragm and steelyard arrangement or with a standard
gauge.
The apparatus is manipulated in the following manner. To either of the
nozzles CC is to be connected a standard gauge, or a diaphragm and steelyard
arrangement, and to the other nozzle is to be connected the gauge to be tested, the
connections DD should be perfectly tight and sound The apparatus must then be
charged with liquid, this is done by turning the hand wheel in the direction which
will send the plunger to the limit of its travel towards the valve F, the valve F
being open The bib or spout S is then to be connected with a supply of water or
other liquid. The hand wheel is then turned so as to cause the plunger to be
withdrawn from the cylinder A until the packing H reaches the guide nut L. The
valve F, is then to be closed and by turning the band wheel, the plunger is to be
driven in the direction of the valve F so as to force the liquid into or against the
standard gauge, or. diaphragm and steelyard arrangement, as the case may be, and
the gauge to be tested. Pressure is thus obtained and indicated, and comparisons

page_text: can be made. To obtain vacuum it is not necessary to have any liquid in the
apparatus and the action of plunger is exactly the reverse to that for obtaining
pressure, but as air is more elastic than a liquid it may be necessary to operate the
plunger G more than once to produce the required degree of vacuum, the apparatus
will therefore be worked as follows:-the plunger G being at the extremity of its
travel the valve T is opened so as to establish communication between the
cylinders, the plunger G is then withdrawn from its cylinder, as hereinbefore
described. If the required degree of vacuum is not thereby produced the valve T
is closed and the plunger G is returned to its original position, the valve T is then
opened and the action repeated. If more vacuum be required the operation must
be gone through again.
In the foregoing example I have supposed that there are only two nozzles upon
the cylinder B but there may be, as herein before mentioned, more than two, or
there may, in addition thereto, be one or more nozzles on other parts of the
apparatus, therefore, more than one gauge may be tested at the same time, but
should there be a less number of gauges to be tested than there are nozzlos, those
nozzles to which no gauges are connected, must be securely closed by a plug or a
cap or by other suitable means.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. A machine constructed, arranged and set up in the manner and for the
purposes herein before described and illustrated in the accompanying drawings.
2. In a machine or apparatus for producing pressure, or vacuum, the combination
of the plunger G having a female screw, with the screw I: the screw being
attached to a bandwheel, or its equivalent, carried in a bearing in the manner
substantially as herein before described and illustrated.
3. In a machine or apparatus for producing pressure, or vacuum, the combi-
nation of the plunger G having a female screw, and the screw I with the shutting
off valve T in the manner, substantially, as herein before described and illustrated.
Dated this 24th day of April 1886.