A patent was taken out in 1826 by Mr. Walter Hancock, of Stratford, in Essex, for the manufacture of water or other piper, that should be as durable, but less expensive, than the cast-iron pipes we have been just describing; and as the manufacture of these may be advantageously conducted in situations where the products of a foundry cannot easily be procured, we annex the ingenious process of the patentee.
Sheets or strips of iron or copper are selected of the appropriate lengths, breadths, and thicknesses, for making the proposed pipes. In making a cylindrical pipe, the sheet must be of greater width than the circumference required, and of a true rectangular figure. Each of the two opposite edges are then to be doubled or folded back, as shown by the annexed figure a. The sheet is then to be bent round by the ordinary means into a cylindrical form, and the edges turned back as shown in the annexed Fig. b. A slip of sheet iron, of the same thickness and length as the before-mentioned, with parallel sides, is then doubled back at the edges in the same manner as shown at c; this piece is then slided over the ends of b, so that the edges of both shall mutually envelope and brace each other, in the manner exhibited in the following Fig. d; the joints thus made are then brought into close contact by hammering. This method of joining the tubes may with equal facility be effected on the inside, if in turning the sheet up into the cylindrical shape it be bent the reverse way, as shown in Fig. e. The projecting part of the joint being inside, is preferable in many cases.
The tube, as now described, the patentee calls his inner tube, to distinguish it from the exterior covering it afterwards receives, to increase its strength and durability. This is effected by winding round the inner tubes iron hoops, or narrow strips of metal, rivetted end to end in a spiral direction, with the coils in close contact generally, but sometimes a little apart, to give them elasticity in bending. The operation is performed by fixing the tube upon a wooden roller, of a diameter nearly corresponding with the internal diameter of the said tube, and the roller is mounted horizontally upon an iron axle in a fixed frame, with a handle for turning it round at one or both ends. One of the ends of the hoop iron is then made fast to the end of the tube by a rivet, and being held in an oblique position with the axis of the roller, the latter is turned round, while sufficient tension is given to the hoop iron to make it lie close and tight to the tube during the coiling operation; after which it is fastened to the other end of the tube by another rivet.
A hoop or ring is now put on hot, to each end of the tube at right angles with the axis, for the greater security of the previous binding; these end hoops, as they cool, contract in their circumference, and consequently fix themselves, and bind all the parts of the tube firmly together.
The tubes are next to be immersed in liquid cement, contained in a vessel of suitable capacity to receive them; the cement is thus made to enter and fill up every fissure or interstice between the several parts of the tubes. The cement is composed of the following ingredients and proportions, mixed and melted together: viz. 2 lbs. bees' wax, 2 1/2 lbs. linseed oil, 12 lbs. common white resin, 18 lbs. pitch, 1 lb. tallow, and 16 lbs. of plaster of Paris, or Roman cement, or quicklime in powder; and when it is desired to give a greater degree of elasticity and toughness to the cement, 2 lbs. of Indian rubber, previously dissolved in five quarts of oil of turpentine, are to be added.
To protect the outside of the pipes from rust, one or more layers of canvas, saturated with the cement, are to be wrapped round it. In lieu of this, sometimes the patentees put a tube of sheet iron for the external covering, and fid up the interstices between with cement.
In order to connect such pipes together, a tube, similar to those already described, is prepared, of a length somewhat more than its diameter, which should be about three quarters of an inch greater than the diameter of the tubes to be connected; the latter being placed end to end, with the piece of connecting tube extending equally over each, and the annular space between the tubes are filled in with cement. To prevent the cement from getting in between the two opposed ends of the tubes, they are previously brought into contact, and covered at the point of junction, with a pley or two of oakum. At each end of the connecting tube is fixed a wooden ring, and the annulus thus rendered uniform is filled with the cement, in a hot and liquid state, by an iron syringe inserted in a hole made in the connecting tube. Instead of iron, the patentee makes use of wood sometimes for his inner tubes; these are composed of a number of pieces laid longitudinally side by side, and arranged in a circle. This tube is put upon a wooden roller, similar to the before-mentioned, and being turned round, it is covered spirally with iron hoops. For large sized tubes, wood is preferable, as being stiffer and stronger than those made of sheet iron of moderate thickness.
The wooden tubes, bound in iron, are completed by similar processes to those described in the other kind.
Bagshaw's patent earthen pipes are thus made: - Chlindrical plugs of wood, of the same diameter as the bore of the intended pipe, and of the same length, are coated with a sufficient thickness of clay, or plastic earth, which has been duly prepared in the manner practised in the potteries. To perfect the exterior form of the pipe, an external mould is to be employed, consisting of two semi-cylindrical pieces, which are to be placed on each side of the intended pipe, when the edges are to be brought together by screwing them up, which will press out the superfluous clay from the mould; the exterior mould being next removed, the pipe will be found completely formed upon the plug: in this state it is to be dried; after which the plug may be easily withdrawn, and the pipes finished, by baking them in an oven. The pipes are to be connected together by inserting the smaller end of one into the larger end of another, and filling up the interstices between them with Roman or other soft fluid cement.