_Governor or Regulating Guage._
The governor or regulating guage, the construction of which has already
been detailed, page 171, we shall here consider as an instrument by
means of which the gas flames of lamps and burners are kept of one
steady and uniform magnitude.
The velocity of the gas in the mains and pipes of supply, is in the
first instance as various as there are differences in the altitude and
extent of the mains and pipes of supply. A main, at one place will
furnish with a certain pressure of gas, a flame one inch high, while at
a different altitude it will furnish a flame double that height.
If again the direction of the pipe has many turns or angles, and
contractions, the velocity of the gas will be different on that account,
than if it were direct and uniform. And if the pipe is of any great
length, and of an uniform bore, but unequally furnished with veins or
branch pipes at certain parts, the burners will be very unequally
supplied with gas, those which are near its head will be supplied with a
fuller stream of gas, than those which are situated towards its
termination.
And independent of these differences thus arising from diversity of
local positions, there will always be one grand variety in the velocity
of the gas, occasioned by the variety of periods during which lights are
required by different individuals supplied from the same main or system
of pipes, as for example: when a certain number of burners are to be
supplied, and it happens that one half of these burners are shut sooner
than the rest, then in consequence of this, the velocity of the gas in
the mains will be materially altered.
The inequality thus occasioned, may be seen particularly exemplified in
the case of houses situated in the vicinity of any large establishment,
such as either of the great theatres of the metropolis, and supplied
with gas from the same mains. While the theatres are open, the lights in
the adjacent houses are low and feeble, often too much so for the
necessary purposes of the consumer, but the moment the theatres are
shut, the great quantity of gas which they previously carried off, being
transferred to such of the private houses as continue to be lighted, the
gas flames at the latter are raised to an extravagant height, and burn
with an intensity which makes the gas light partake more of the
character of a nuisance than of a benefit.
It may be necessary for the better appreciation of the extent of this
nuisance to observe, that it does not arise merely from the excess of
light produced, but from the imperfect combustion of the gas, and hence
a disagreeable odour is produced. When the flame is suffered to rise
beyond the standard height, the combustion of the gas becomes imperfect,
part of the gas passes through the flame unburnt, and occasions the
source of the offensive odour alluded to, which the gas lights never
produce when the combustion of the gas is complete. The remedy for all
these inconveniences thus resulting from the various degrees of
velocity of the gas in the mains, is to be found in the instrument now
under description.
The effect of this machine, as already mentioned, is, that it causes the
gas to issue from the aperture of the burners or lamps with one uniform
velocity, whatever may be the variations which take place in the
pressure which urges the gas to pass through the pipes of supply. And
such is the efficiency of the operation of the machine, that it
regulates the flow of the gas through any burner, tube, or opening, with
a greater degree of exactness, than the centrifugal apparatus, regulates
the action of the steam engine.
The construction of the regulator to effect this purpose is precisely
similar to the apparatus already described, page 171. When applied for
regulating the magnitude of the gas flames, it is of course usually made
much smaller, of iron plates, japanned within and without. Fig. 4, plate
III., exhibits a perspective view of the machine; _a_, is the inlet
pipe, _b_, the outlet pipe; P, is the regulating cone, passing through
the regulating aperture _x_, T. The floating vessel _u_, _x_, _y_, _z_,
receives the gas introduced into the machine; A, B, C, D, is the outer
air tight case of the regulator.
_Directions to Workmen for fixing the Governor and Gas Metre._[49]
[49] Copied from Messrs. Clegg’s and Crossley’s printed directions to
workmen, for fixing governors and gas metres.
The governor must be fixed perpendicularly, so as to admit its floating
vessel _u_, _x_, _y_, _z_. Fig. 4, plate III., or fig. 9, plate III., to
be taken out of the outer case of the machine if occasion should require
it.
The gas enters into the machine from the street mains at the lowest
branch _a_, and passes out of the machine by its highest branch _b_.
In connecting the pipes of supply, particular care must be taken that
the work is not _bound_, or the governor by any means rendered leaky. It
must be filled with water to the top of the central tube.
Examine the workmanship of the machine to see that it is perfect, and
that the regulating cone P, is firmly secured to the top of the
floating vessel and well centered. The floating vessels _u_, _x_, _y_,
_z_, should clear the sides of the outer case of the apparatus by a
quarter of an inch; and when sunk down, it should rest even upon the top
of the central pipe, which conducts the gas into, and out of, the
machine. The aperture in which the cone moves will then be at its widest
opening, and when the floating vessel _u_, _x_, _y_, _z_, has risen to
its highest elevation, the regulating aperture _x_, T, will be closed.
In this situation particular attention must be paid, that the regulating
cone does not stick or rub in any part, but that it descends freely.
To the lower extremity of the floating vessel _u_, _x_, _y_, _z_, may be
adapted an air vessel for the purpose of reducing the pressure of the
gas.
The governor must be so fixed, that the water which may condense in the
pipes leading to the burners shall drain back to the street mains, in
order that it may not accumulate in the machine so as to impede its
operations; for this purpose the gas pipes should have a fall of half an
inch in three or four feet.
When the locality of situation will not admit of the water that may
accumulate in the pipes falling back to the mains, its accumulation
within the governor above the proper level of the water is prevented by
an inverted siphon affixed to the machine, which allows the water to
drain off without any escape of the gas.
The governor must be firmly fixed to the nearest beam or wall, as the
least vibration will render the lights connected with it unsteady.
When a situation cannot be obtained sufficiently warm to prevent the
water from freezing, the machine must then be wrapped round with woollen
cloth, or any other bad conductor of heat. The cellar where the gas
enters the house, has generally been found the most convenient
situation.
For supplying any deficiency of water which the governor may require; a
small funnel with a curved tube is placed for this purpose at the top of
the governor. When the governor is filled to its proper height, the
water will begin to run out of the siphon.
The mode of regulating the height of the flames will be stated
presently.
Fig. 11, plate III., exhibits a portable governor or regulating guage,
combined with a gas metre in one case. A, is the inlet pipe which
conveys the gas into the machine, and B, is the pipe leading from the
governor to the lamps or burners. D, a label expressing the quantity of
gas discharged by one revolution of the wheel, and the number of lights
which the metre is capable of supplying when the pressure of the gas in
the inlet pipe is of a density sufficient to support a column of water
of half an inch in height.
In those situations where the pressure of the gas is equal in density to
support only a column of water one-quarter of an inch in height, a metre
of a larger capacity must be adopted for supplying the same number of
lights; and if the pressure of the gas be equal only to support a column
of water one-eighth of an inch in height, the capacity of the metre must
be still larger, and thus the capacity may be increased so as to equal
every pressure that may occur. The index which registers the number of
revolutions, and consequently the quantity of gas which passes through
the metre, is shut up in the projecting case, near H, furnished with a
lock and key.
Previously to the gas metre being filled with water, ascertain that the
regulating cone is screwed perfectly air tight into the top of the
floating vessel which receives the gas, and that the regulating aperture
in which the cone moves, together with its spindle and guide rods, work
perfectly free and without friction. Raise the floating vessel to its
highest elevation, thereby closing the regulating aperture suddenly with
the cone; in this situation it must not rub when turned and tried on
every side, but descend with the least friction.
The gas metre and regulator being thus examined and fixed, the machine
may be supplied with the requisite quantity of water in the following
manner:
Open the stop-cock which admits the gas into the machine; open also the
aperture E, which serves to show the pressure of the gas in the machine,
and likewise the opening G, which lets out the air whilst water is
poured in at the aperture H. The superfluous quantity of water will run
out by the siphon tube at K.
Pour water also into the governor until it runs out at the aperture at
M; and when this has been accomplished, till the gas metre with water
at the opening H, until it overflows at the aperture K, when the surface
of the water will appear at the cypher line on the scale board. The
apertures F, G, H, K, and M, may then be closed, and the machine is
ready for action.
Near to N, is an aperture communicating with the stuffing box in which
the axis of the machine moves, and through which it should occasionally
be supplied with a small portion of melted tallow.
To adjust the height of the gas flames of the burners, so that they be
all uniform, open the stop-cock which admits the gas into the metre, and
open also the stop-cocks of the burners, and as soon as the air has
become discharged by means of one or two revolutions of the metre, light
all the burners. Adjust the height of the flames in the first instance
by their stop-cocks, that they become all of an equal height, which
should be about double the diameter of the flame; if any of the flames
be too low when the stop-cock is fully open, a small weight must be
placed upon the top of the floating vessel of the regulator, sufficient
to produce the required flame at the burner, and then again adjust the
remaining lights by their stop-cocks as before stated; this being done,
the aperture to which each burner is screwed must be sufficiently
narrowed, that it will admit no more gas than is requisite for the
required height of the flame, when the stop-cock is fully open. The
diminution of the aperture of the stop-cock may be effected by a brass
plug fitted into it, with a hole in its centre, which must be gradually
widened with a drill until the flame has required the proper height. It
is recommended, instead of adding weight to the floating vessel of the
regulator, that the tubes which supply the gas be sufficiently capacious
to render the weight unnecessary.
The burners should also be examined from time to time. Observe that the
plugs, sockets, and every other part of the gas metre and regulator be
air tight, and that there be no escape of water or gas.
An escape of gas, either from the metre or from any of the tubes or
burners, will be discovered by looking at the index of the metre, as the
wheel cannot fail to move whenever there is an escape of gas, if the
stop-cock is open which supplies the gas to the metre. The place where
the gas escapes will be found in the usual way, either by the odour
which the gas produces, or by passing a lighted taper over the apertures
and connections of the metre, and along the tubes leading to the
burners, which will cause the gas to take fire at the place where the
leak happens to be.
The following remarks will assist the workmen in correcting any
irregularities which may occur in the lights connected with the
apparatus.
A diminution, or extinction of the lights, may be occasioned by a
deficiency of water in the gas metre or regulator; when this occurs the
necessary quantity of water must be supplied as before directed up to
the cypher line on the scale board E, of the metre, and opening the
aperture M, where it may be seen when the water has risen to the proper
height in the governor.
A diminution of light may also be occasioned by some obstruction or
contraction of the tubes which supply the gas, or by a diminution of the
pressure of the gas in the mains, to which the metre was originally
adjusted.
When the lights increase above their standard height, and are variable
with the changes in the pressure or velocity of the gas in the mains or
tubes of supply within the house or place, lighted, there is then reason
to believe that the governor is not performing, which may arise from the
following causes. Its floating vessel _u_, _x_, _y_, _z_, may have
become fast by the friction of the spindle or guide rod, requiring
cleaning, or by an accumulation of water in the air-vessel of the
floating vessel _u_, _x_, _y_, _z_. The water may be drained off at a
small plug by taking out the floating vessel. The same inconvenience
would arise from a diminution in the proper level of the water.
In order to ascertain that the governor performs correctly, observe at
the time of lighting or extinguishing any of the burners connected with
it, that its floating vessel rises and falls every time the stop-cock is
opened, and that the lights do not suffer any material change.
An instantaneous starting or dancing of the lights, is generally
occasioned by an accumulation of water in the tubes through which the
gas passes; if this should happen in the vicinity of the metre and
governor, it may be drained off at the aperture K. A provision for a
like purpose is also made at the bottom of the governor when detached
from the metre.
In order at any time to ascertain the pressure of the gas in the metre,
close the stop-cock which admits the gas, and open the aperture G and F,
which will shew the level of the water on the scale board E. This being
first observed, close the aperture G, and open the stop-cock, and the
pressure of the gas in the metre will be indicated by the rise of the
water on the scale board E, above its original height.