Improvement in Appliances for Indicating and Regulating Fluid Pressure.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvement in Appliances for Indicating and Regulating Fluid
Pressure.
I, JOHN HUTCHENS GARTRELL, Surgeon Dentist, of 47, Chapel Street,
Penzance, in the County of Cornwall, do hereby declare the nature of this inven-
tion and in what manner the same is to he performed, to be particularly described
and ascertained in and by the following statement :-
The present invention relates to combined pressure gauges and pressure regulators,
chiefly applicable for automatically regulating the flow or supply of gas to the
burner or burners of boilers or vulcanizers used in the manufacture of dental plates,
while indicating the pressure of steam within such boilers.
The object of the present improvement is to simplify the manufacture or
construction and thereby to reduce the cost of such apparatus.
This combined pressure gauge and regulator chiefly comprises a pointer or hand
controlled by a Bourdon tube or, a Schäffer diaphragm, so as to indicate on a
graduated scale the steam pressure acting on the said tube or diaphragm ; a valve
controlled by the devices that move the said index hand, and another pointer
connected with the valve seat or opening, so that by adjusting the latter the pointer
will be caused to indicate on a graduated scale the pressure at which the valve will
close.
In further describing the invention, reference will be made to the accompanying
drawings, of which
Fig. 1 is a vertical section of an apparatus embodying my invention;
Fig. 2 is a front view and Fig. 3 a back view of the same, when the gas supply
pipe is open;
Fig. 4 is a front view and Fig. 5 a back view of the same, when the gas inlet is
closed.
In Figs. 3 and 5 the cover of the valve chamber is supposed to have been
removed.
Fig. 6 is a plan of the valve casing and of the parts connected or made in one
piece with the same.
The general construction and appearance of the pressure gauge is similar to that
of an ordinary Bourdon or Schäffer gauge. In the drawings A represents a
Bourdon tube, connected by a link a with a short lever B which is fixed on the
axle C carrying the index hand D. The latter shows on a pair of graduated
scales E and e the steam pressures and the temperatures corresponding to various
positions of the Bourdon tube. M represents the back or casing of the pressure
gauge, P the ring or rim which holds the glass cover, and N the pipe through
which the steam enters the tube A. The regulating valve K is situated in a small
gas chamber fixed to the back of the pressure gauge, and the central spindle C
carrying the index hands extends through the back of the gauge into the valve
chamber, where it carries the regulating valve.
The valve chamber has a gas inlet and an outlet I, the inlet being preferably
placed at the back of the valve chamber, while the outlet pipe passes through the
circumference of the chamber, and is arranged in such a manner, that its mouth i
can be closed by the regulating valve K, when the pressure has reached a given
limit. In the instruments hitherto made, the central spindle has its bearing in
the rear wall of the pressure gauge, M, the said rear wall being provided externally
with a boss which fits into the open base of the cylindrical valve casing.
Now, as this construction rendered it difficult, to make the spindle C exactly
concentric with the boss which guides the valve casing when being turned on its
centre, special precautions were necessary, to ensure, that the valve fits exactly on
Puin Q.77

page_text: the orifice i of the outlet pipe I, at whatever angle the valve-casing may be placed.
For this purpose, the face of the valve was connected with the body of the same by
a pivot, and in taking the instrument to pieces, the valve casing and the spindle C
had to be detached from the back of the pressure gauge separately, one after the
other.
To avoid these drawbacks, I make the bottom of the valve chamber in one piece
with the side of the valve casing F, and provide it with a long boss or sleeve f
extending through the back plate or wall M of the pressure gauge into the interior
of the same, as shown.
Thus, the valve casing F, instead of being open at the bottom and provided with
an outside flange, has a flangeless bottom provided with an external hub or sleeve
which is bored out axially to receive and support the central spindle C, which is
provided with a small stuffing box, to prevent the escape of gas from the valve
chamber into the interior of the pressure gauge. The back plate or wall M of the
latter has a boss ጎ, which is bored out to suit the external diameter of the said
sleeve. In order to hold the valve box F firmly against the pressure gauge, so as
to prevent any accidental motion around its axis, a ring or collar G is screwed to
the inner extremity of the sleeve, immediately behind the boss or bearing of the
back plate M and is secured in position by a set screw y.
The motion of the valve
box around its axis is limited by another screw, or stud o, which passes through a
segmental recess of the bearing and is fixed in the bottom of the box F.
The two pointers or index fingers mentioned above turn on the same axis, one, D,
being fixed to the extremity of the central spindle C, while the other H is
mounted on the front end of a curved arm (shown in Fig. 6) which extends from
the inner end of the sleeve and is bored out to form a bearing for the front end of
the spindle C. The said arm is so arranged as to allow sufficient space for the
motion of the lever B and link a which connects the spindle with the Bourdon
tube etc. The index finger H indicates the position of the valve K with regard to
the outlet i.
The collar or nut G is screwed on so tight, that the friction between itself and
the bearing and also between the bottom of the valve casing and the back of the
casing M will prevent accidental displacement of the valve casing, after the latter
together with the valve seat has been turned into the desired position. If desired,
the valve casing may be secured after every adjustment by means of a set screw
passing through a slotted flange formed on the circumference of the valve casing, or
by other convenient means.
For taking the improved instrument to pieces, it is only necessary, to remove the
two pointers or index fingers, D and H, loosen the set screw which secures the
lever B connecting the spindle C with the link a and Bourdon tube A, and screw
the collar G off the sleeve f, after which the valve casing, together with the
central spindle and valve, may be drawn out from the back.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is ;-
1. In a combined pressure gauge and regulator, of the type specified, a valve
casing closed at the bottom and provided with a cylindrical sleeve or boss supported
and guided in a cylindrical bearing formed in the back of the pressure gauge, said
boss having an axial bore for the spindle which actuates the index hand of the
pressure gauge and the valve, and an arm or extension adapted to carry the index
hand which indicates the position of the valve seat, substantially as described.
2. In a combined pressure gauge and regulator, the combination of a spindle C
carrying at one end the index hand D of the pressure gauge and at the other end
the regulating valve K, with a Bourdon tube or equivalent device connected with
the said spindle and adapted to control the same, a valve casing F containing the
valve seat and provided with a boss fadapted to support and guide the valve
spindle C at the back and carrying an index hand H in front, a pressure gauge

page_text: casing having in front a graduated scale for the two index hands and at the back a
bearing for the boss of the valve casing, and means for retaining the valve
casing axially in position and for limiting its angular or pivotal motion, sub-
stantially as described.
J. H. GARTRELL,
By Fairfax & Wetter;
433, Strand, London, Patent Agents.