Chapter VIII: Part II: Gas-Light (4)

When the cement is wanted for use, take one part of the above powder, and twenty parts of clean iron borings or filings, and blend them intimately by grinding them in a mortar. Wet the compound with water, and when brought to a convenient consistence, apply it to the joints with a wooden or blunt iron spatula.

By a play of affinities, which those who are at all acquainted with chemistry will be at no loss to comprehend, a degree of action and re-action takes place among the ingredients, and between them and the iron surfaces, which at last causes the whole to unite as one mass. In fact, after a time, the mixture and the surfaces of the flanches become a species of pyrites (holding a very large proportion of iron,) all the parts of which cohere strongly together.

The inner parts of the faucet ought to be no larger in diameter than just to fit the spigot. This supports the pipe, independently of the cement, and prevents the risk of hurting the joint from any external stress. The inner faucet is commonly made about 2½ inches deep, and has the spigot inserted 1½ inch into it. The practice of some workmen, is to make the outer faucet, or that which contains the cement, six inches deep, for all pipes above six inches diameter; and to make the faucets of all pipes below six inches, the same depth as the diameter of the pipes. It is usual to make the space for the cement, all round the spigot, from 1 to 1½ inch; that width is required, in order that the cement may be firmly driven into the joint. When the space is very narrow, this cannot be done. On the other hand, when too wide, there is a waste of cement, and a risk of injury from unequal expansion.

FIG. 3. Exhibits a profile view of these kinds of pipes when joined together. The spigot and faucet pipes are liable to burst from the great expansion of the spigot, and the risk of this accident is increased by increasing the space between the spigot and faucet, which requires to be filled with cement.

FIG. 4. Represents a longitudinal section of two flanch pipes, and the modes of connecting them. A and B, show the parts of the pipes; and C and D, the flanches. These pipes are also joined together, and rendered air-tight, by interposing between the flanches rope-yarn, hemp, or some other pliable material, and iron cement, and then screwing up the faces of them by means of the bolts and screw nuts.

FIG. 5. Profile view of the same kind of pipes connected together, A and B, the pipes; C and D, the flanches; E and F, the bolts.

FIG. 6. Represents the method of joining spigot and faucet pipes when they are to have a turn or angle. This method is convenient when the place where the turn required to be made is previously known, and the pipes cast accordingly.

FIG. 7. Exhibits the method of connecting spigot and faucet pipes when they have a round turn. A and B, the junctures of the pipes.

FIG. 8. Represents a longitudinal section of the mode of joining pipes by means of what is called a _thimble joint_. The junctures of the pipes to be connected, are made air tight, as mentioned already, by iron cement. A, the thimble or small cylinder, with projecting edges, which unites the pipes B, C.

FIG. 9. A thimble joint made in two parts, which is sometimes convenient to join pipes. The parts are joined together by screw bolts, and nuts, in the usual manner.

FIG. 10. Section of the same.

FIG. 11. Represents a profile view of what is called the _saddle joint_. It is employed for taking off a branch-pipe. The branch has a piece A B, formed on its end, and fits round one-half of the outside of the pipe from which it is to proceed. C, is called the saddle, which fits round the other half of the pipe. The parts are secured together by screw bolts, and iron cement. By this method a branch may be formed on any part of a gas-pipe, by cutting a hole there, and applying the branch to that place. Where there is much risk of the inequality of expansion, the joints at certain places, should be secured by a soft stuffing of hemp and tallow; but in most cases the joints may be made with iron cement. Lead is frequently used for making the joints of gas pipes instead of iron cement, though cheaper and more easy of repair. The galvanic action which takes place between the lead and iron, soon renders the joints leaky, and the danger is increased by the unequal expansion of the two metals.

FIG. 12. Section of the saddle-joint.

Before the gas is suffered to enter into the pipe, they should be proved to be sound, by the usual process of forcing water into them: The pipes serving as mains, are placed perfectly solid, so that they cannot give way; their course should be rectilinear, having a descent of about 1 inch in 9 or 10 feet, to allow the water of condensation which may be deposited from the gas by a change of temperature to collect readily at the lowermost part.

FIG. 13. Shows a reservoir for collecting the water of condensation which might accumulate in the pipes. It consists of a receptacle, A, in which the water may pass; B, a branch-pipe closed at the top, by means of which the water may be removed, by drawing it out with a syringe. This receptacle is placed in those situations where pipes incline towards each other.

PLATE VII.

Exhibits a perpendicular section of a gas-light apparatus, calculated for lighting towns, or large districts of streets and houses.

FIG. 1. The Retort Furnace. The retorts are placed over each other in one or more rows; so that a certain number of them may be heated by separate fire-places. A, A, shows two of the retorts placed horizontally above each other; B, the fire-place; C, the flue which causes the fire to circulate round the retorts so as to heat them equally in every part; D, the opening of the flue where the fire passes into the chimney; E, the ash-pit; F, a chamber in front of the retort furnace, into which the orifice or mouth of the retorts project; G, G, the doors of the chamber, to enable the workmen to charge and discharge the retorts; H, a funnel shaped hole at the floor of the chamber F, through which the red hot coke as it is discharged from the retorts passes into the arched vault I; K, the syphon tube; L, the horizontal condenser[41]--the action of both of these pipes have been already explained, p. 168; M, main pipe, which conveys the liquid substances from the condenser, to the tar cistern, fig. 3, and which conducts also the gazeous products into the lime machine, fig. 2; N N, shows that part of the pipe which is interposed between the tar cistern, fig. 3, and the condensing pipe M,--it passes in a serpentine direction along the inner sides of the gasometer cistern, and, like the so-called _worm_ in a distillatory apparatus, condenses the products which escape in a vaporous state from the condenser L; O, shows the place where the serpentine pipe N N, passes again out of the gasometer cistern, and its communication with the lime machine, fig. 2, and tar chamber, fig. 3. The action of the lime machine is as follows: The liquid products evolved from the coal, having been deposited in the tar cistern, fig. 3, by means of the serpentine pipe N, N, the gazeous products which accompany it, are conveyed by means of the pipe P, which branches out from the pipe O, into the interior receptacle of the lime machine marked Q, which consists of a vessel open at the bottom, and closed at the top, where it communicates with the pipe O. As the gas accumulates in the interior part Q, of the lime machine, it is made to pass through the liquid which it contains, namely, slaked lime and water; and escapes through appertures made in the horizontal partitions R, R, R, R, into the outer vessel, S, of the lime machine and from thence it is conducted away by the pipe T, T, T, into the additional washing apparatus, of the gasometer; fig. 4, the construction of this apparatus, greatly resembles the lime machine, fig. 2, namely, V, is a water pipe, proceeding from a cistern U, placed 3 or 4 feet above the orifice of the pipe V; T, T, is the gas-pipe, covered with a hood, marked W, and immersed in a small cistern, having horizontal perforated shelves, like those in the lime machine--they fit close to the hood. The gas which enters the hood W, meets with a shower of water delivered by the pipe V. The gas, as it passes through the holes in the horizontal partitions, is, therefore, again washed and thoroughly purified from foreign gases which may have escaped the action of the lime machine; Y, is a waste pipe, the lower extremity of which is sealed by being immersed in water,--it serves to carry away the water delivered by the pipe V, as it has been acted on by the gas. The summary action of this gas apparatus is, therefore, as follows: The liquid products obtained from the coal during the distillation are first deposited in the main condenser L, by means of the pipe K, and from whence they cannot escape until a quantity of tar has accumulated in it to a certain height, and by this means, one of the extremities of the pipes K, K, becomes immersed and hermetically sealed by the liquid which the condenser L, contains. The liquid products, after having accumulated to a certain height in the condenser, overflow the perpendicular portion which it contains, and discharge themselves into the pipe M, from whence they are transported into the tar cistern, fig. 3, by means of the system of pipes N, N, O, whilst the gazeous products are made to pass by means of the branch pipe P, into the lime machine, fig. 2. From this part of the apparatus the gas passes through the pipe T, T, T, into the additional or smaller washing apparatus placed upon a tressel in the cistern of the gasometer, where it is again exposed a second time to the action of a current of fresh water; and from this vessel the gas ascends into the gasometer. The gasometer is furnished with a pipe A, closed at the top, and fixed in one corner of the gasometer, but open at the bottom; it includes another pipe marked B, which communicates with the main pipe leading to the burners, or place where the gas is wanted. The pipe A, which slides over the pipe B, is perforated at the top, the gas passes through these perforations and is thus made to enter into the pipe B, and disposed of as mentioned. C, C, is a tube of safety adapted to the gasometer; its lower extremity remains sealed by the water in the cistern so long as the gasometer is not overcharged with gas; but, if more gas should be made to enter the gasometer than it is destined to receive, this pipe then delivers the gas into the funnel-shaped tube D, which reaches through the roof of the gasometer house, and thus the superfluous quantity of gas is conveyed away into the open air.

[41] The condenser in this apparatus is placed at right angles to the
row, or rows of retorts. It is furnished at one extremity with a
partition placed perpendicularly, and of a height equal to about
one-half of the diameter of the condenser. The object of this
partition is to prevent the tar, &c. deposited in it, to seal the
pipes K, K, and not to discharge itself into the pipe M, till this has
been effected. The partition is seen in the drawing.

The cylindrical vessel P, of fig. 3, surrounding the orifice of the pipe O, which delivers the tar into the tar cistern, fig. 3, serves to keep this pipe constantly immersed into a portion of tar, so that the contents of the cistern may be drawn off by the cock without admitting air into any part of the apparatus. The tar cistern has a small hole at the top, to allow the air which it encloses to escape, as it becomes filled with tar and ammoniacal liquor. The main condenser L, is placed, as shown in the drawing, higher than the level of the water in the gasometer cistern, to allow a free descent of the distillatory liquids as they pass from this vessel along into the pipes M, N, O, &c. The cistern of the gasometer, as well as the lime machine, and tar cistern, are constructed of cast iron plates, bolted and cemented together with iron cement. The gasometer is made of sheet iron plates rivetted together--E, E, are two iron stays--G, G, are friction wheels.

_METHOD of correcting the relative pressure of the Gasometer, so as to cause the gas which it contains to be uniformly of an equal density._[42]

[42] For this elegant contrivance we are also indebted to Mr. CLEGG.

We have mentioned already that the pressure of the gas in the gasometer should be invariable, for it is obvious that the weight of the gasometer is constantly increasing in proportion as it fills with gas, and rises out of the water--see p. 88, and 167. To render its pressure uniform, we first take the _absolute_ weight of that part of the gasometer which becomes immersed in the water, and knowing the _specific weight_ of the substance of which it is composed, we divide its absolute weight by the specific weight of the substance of which it is composed; and this being done, we make part of the chain, (measured at right angles from the axis of the wheels over which it passes downwards towards the top of the gasometer,) which is equal to the length of that part of the gasometer which becomes immersed in water, equal in weight to the specific gravity of the substance of which the gasometer is composed. For example, let us suppose that the part of the gasometer which becomes immersed in water weighs 861 _lb._ and that it is composed of sheet iron, the specific gravity of which, in round numbers, we will take to be 7. It is then evident, that the part of the chain of the gasometer measured downward from the axis of the wheel over which it passes, and which is equal in length to the height of the gasometer, must be loaded with a weight of, or must itself weigh, 123_lb._ for this would be the weight of the water displaced by the gasometer; or let us suppose the gasometer to be made of sheet copper, the specific weight of which (omitting decimals) is 8; and that the absolute weight of the gasometer is 1792_lbs._ then the chain of the gasometer equal in length to the height of the gasometer, immersed into the water must weigh 224_lb._ for this would be the weight of the quantity of water which the gasometer displaces. This being accomplished by then adding or diminishing the absolute or balance weight of the gasometer, any desired uniform pressure may be effected, and the same bulk of gas will always be of the same specific gravity.

DIRECTIONS TO WORKMEN ATTENDING THE GAS-LIGHT APPARATUS[43].

[43] Copied from a printed direction drawn up by Mr. Clegg, for the
use of workmen.

Particular care must be taken to make the joints of the mouth-pieces of the retorts perfectly air tight, which may be done in the following manner:--Take some common clay, dry, pulverize, and sift it, then add as much water as will make it into the consistency of treacle; make the mouth-piece and the lid of the retort clean, lay this luting thinly over the turned part of the lid, press the lid so luted gently to the mouth-piece, and then secure it moderately, by means of the iron wedge: if the workman observes this rule, he will never fail to make good joints; but if, on the other hand, the operator is careless and neglects to remove the old luting, &c. from the turned or smooth part of the mouth of the retort, and thereby cause a bad joint, the consequence will be the loss of a considerable quantity of gas, and a very disagreeable smell and smoke.

The bridge or row of bricks of the flue C, of the retorts, should never be made hotter than a bright red, which may be regulated by the door of the ash-pit being kept close shut when the fire is getting too hot. If the operator neglects this, and suffers the fire-bricks to arrive at a bright white heat the retorts will soon be destroyed, and bad gas be produced.

The gasometer should be well examined, at least once a week, to see if it leaks, by the following method, viz. Let the main stop-cock be shut, then make a mark on the gasometer at the water’s edge when it is full or nearly of gas, there being no gas coming from the retorts at the time, and if the mark sinks in the water, the gasometer leaks; to find out the place, walk slowly round it, and you may perceive the leak by the smell, apply a lighted candle to the part suspected, and if there be gas issuing from it, it will take fire, and perhaps appear like a small blue flame--blow it out, and mark the place: thus proceed round the gasometer till you have found all the places; if you perceive a smell, and yet cannot produce a flame in the part suspected, take a brush with a little thin white-lead paint, and lay it on the part where you think the leak is, and, if it be there, the gas which escapes from the leak, will immediately turn the paint brown. After the sides of the gasometer have been well examined, and secured by dipping a piece of cloth about the size of a shilling, into some melted pitch, tempered with a little bees-wax and tar, apply the cloth whilst hot to the place with the end of your finger, rubbing it till it is quite cold; next examine the top of the gasometer in the same manner,--when it is about two feet high in the cistern, it will then be better to get at. The water in the cistern should always be kept within 3 or four inches of the top, if suffered to sink much lower without replenishing, the gas will not pass through a sufficient quantity of water, and oily particles will be apt to condense in the pipes, to their great detriment.

The only thing to be observed in the place lighted is, that the lamps and pipes are not suffered to be touched on any pretence whatever, but by the person entrusted with their care. When a lamp is not wanted, it must be completely shut off from the pipe which supplies it, by a stop-cock provided for the purpose, and not opened again but when a flame is held over it; not a lighted candle, as the tallow is liable to drop into the lamps; lighted paper is better.

ESTIMATE OF THE PRICE OF A GAS-LIGHT APPARATUS, _IF ERECTED IN LONDON_,

Capable of affording, every 24 hours, Light equal to 40,000 Tallow Candles, six in the pound, burning one hour.

£. s.
Gasometer, to contain 10,000 cubic feet of gas 236 0

Wheel-work, regulating chain, ballance-weight for } 160 11
ditto, with wooden framing }

Wrought iron cistern for gasometer--36 feet wide, } 500 0
24 feet long and 16 feet deep }
(_It would weigh about 16 tons._)

Wooden framing built around it, to secure ditto 150 0

Condenser, cistern and communicating pipes 126 0

Lime machine, made of cast iron plates 82 0

Gasometer-house, built of frame-work and weather-boarded 250 0

Twenty-four retorts set in brick-work, with furnaces } 336 0
for ditto, compleat }

Sundries 100 0
---------
£ 1940 11

* * * * *

A gas-light apparatus complete for work, capable of affording every
twenty-four hours a quantity of light equal to 1,400 Argand’s Lamps,
each lamp equal in intensity to six candles, six in the pound, burning
for five hours, will cost 3,500_l._ if erected in this metropolis.

LONDON Price List of the most essential articles[44] employed in the erection of a Gas-Light apparatus.

[44] All the articles are warranted to be perfect and of the best
kind. They are delivered free of expence at any wharf between London
and Westminster-bridge.

Sheet-iron pipes brazed.
_s._ _d._
¼ inch in diameter 0 4 a foot}
⅜ ditto 0 4 ditto}
½ ditto 0 5 ditto}
⅝ ditto 0 6 ditto}
¾ ditto 0 6½ ditto} in
⅞ ditto 7 ditto} 15
1 inch, ditto 0 7½ ditto} to
1¼ ditto 0 9 ditto} 18
1½ ditto 0 10½ ditto} feet
1¾ ditto 0 11 ditto} lengths.
2 inch, ditto 1 1½ ditto}
2¼ ditto 1 4 ditto}
2½ ditto 1 5 ditto}
3 inch, ditto 1 6½ ditto}
Copper pipes brazed ¼ inch 0 4 per foot
Ditto, ditto, ditto ⅜ inch 0 5½ ditto
Gas-light cockspur burners with stop-cock 2s 6d to 3s 6d
Argand’s lamps, with glass-holders, from 3s to 4s 6d
Cast-iron retorts, weighing 7 cwt. at 15s 6d per cwt £5 8 6
Mouth-piece for ditto, compleat 1 14 8
Cast-iron door frames for retort furnace 1 0 0
Furnace bars 10s. per cwt.
Sheet iron for gazometer (No. 23) 24s. per cwt.
Gazometer chains, 5d per lb.
Ballance weights [Plates] for gazometer, 9l 10s per ton.
Cast-iron cistern plates
------------------------ smaller size for lime machine, 18l per ton.
------------------------ middling size for tar cistern, 16l ditto
------------------------ largest size for gazometer cistern 14l ditto
Cast-iron flanch pipes 2-inch diameter, at 5s per yd. in 6 feet lengths
ditto 3 ditto 6s ditto 6 ditto
ditto 4 ditto 8s 6d ditto 9 ditto
ditto 5 ditto 10s ditto 9 ditto
ditto 6 ditto 12s ditto 9 ditto
ditto 7 ditto 13s 6d ditto 9 ditto
ditto 8}
ditto 9} 11l. 5s. per ton 9 ditto
ditto 10}
ditto 11}
½ inch nuts, screws and washers to put iron pipes together 7d. per lb
⅝ ditto 7d. ditto
¾ ditto 6d. ditto
English bar-iron 13l. per ton
Best, ditto 18l. ditto

_FINIS._

_London Pub. April 1-1815, at R·Ackermann’s, 101 Strand._]

Transcriber’s notes

The entries in the Table of Contents do not always conform to the chapter and section headings in the text. Both have been retained as in the original work.

The errata have already been incorporated in the text; the error mentioned as occurring on page 24 actually occurs on page 22.

The original language, including inconsistencies in spelling, hyphenation, punctuation, formatting, etc. has been retained, except as mentioned below.

Unclear parts of the text have been checked against the on-line copy of this book of the Eidgenössische Technische Hochschule Zürich.

Fractions like ½ and 1-10th have both been retained.

Page 90, Van Dieman, Troostwyck: Jan Rudolph Deiman and Adriaan Paets van Troostwijk.

Changes made to the text:

Obvious punctuation and typographical errors have been corrected silently.

Some footnotes, tables and illustrations have been moved; some tables have been re-arranged.

Other changes:

Page 23: any surfaces changed to any surface

Page 26: opening or shuting changed to opening or shutting

Page 47: A New changed to A new

Page 48: trafic changed to traffic; footnote [10]: corporated changed to incorporated (cf. errata)

Page 53: This combustion changed to The combustion (cf. errata)

Page 64: Cleg changed to Clegg (cf. errata); footnote anchor [14] moved from next page (cf. errata, footnote anchor *); communicates changed to communicated (cf. errata)

Page 67: 1250 + 2 = 2500 changed to 1250 × 2 = 2500

Page 69: Mr. LEE changed to “Mr. LEE for consistency

Page 72: closing quote mark added to letter

Page 96: pure coal- changed to pure coal-gas

Page 102: sub acetate changed to sub-acetate

Page 118: ball 6 changed to ball _b_

Page 119: _e_, are changed to _e_ _e_, are

Page 125: 180 degree changed to 180 degrees (cf. errata); footnote [28]: may he compleatly changed to may be compleatly

Page 131: and make changed to and makes

Page 132: coal changed to coal-tar (cf. errata)

Page 158: Nortou Falgate changed to Norton Falgate; a about changed to about

Page 165, table: 10,509 changed to 10,500.