Figs. 1, 2, 3, and 4, of Plate LXXIX., are different sections, to explain the structure of a close copper which contains 300 barrels. AA, in all the figures, denotes the external brickwork, which is a cylindrical wall, built upon the arches, as shewn in Plate LX XVII. In the lower part of this is the ash pit 13, and the fire-grate placed over it, being partly supported by iron pillars. CCC is the copper, hung in the brickwork by a project ing ring of a few inches, at the place where the hemis pherical dome G joins upon it. The dome is surround ed by a copper from DD, to contain the water which is intended for the succeeding mash, or afterwards for the wort produced by the mash. This liquor is heated with the steam produced by the copper, which is conducted up a large tube E, rising from the center of the dome. To the top of this, four smaller pipes FF, Figs. 2 and 3, are joined, turning down to the bottom of the pan, and open at their lower extremities, by which means the steam is conducted beneath the liquor contained in the pan, and by bubbling up through it, soon communicates to it a considerable degree of heat. A recess is made at X, Figs. 2 and 4, in the copper pan, to expose the dome G ; and in this place is the main hole for entering to the copper. Another of these main holes is provided in the top of the copper, at the upper end of a large tube II, Figs. 2 and 4, rising from the dome. I is the chimney to the copper, situated over the fire door a, Fig. 3, and the chimney has an arch in it, to give passage to the lire door. The course of the flues is shewn in Fig. 1, which is a horizontal section, taken a little above the level of the grate bars, upon which the fire rests On each side of this grate a jamb of brickwork K K is built. This supports the bottom of the copper, and compels the flame and smoke to go backwards, and surround the copper, by rising up in the dark space shewn in Figs. 3 and 4. It then turns round in the two semicircular passages over and behind the jambs K K, Fig. I, and enters the chimney by the opening at L, Fig. 3. The chimney is double, having a partition up the centre, which divides it into passages, one of which is appro priated to each flue. The opening L is furnished with an iron door, which can be closed at pleasure ; and the bottom of the chimneys are likewise shut by iron doors at d, Fig. 3, which slide back horizontally when they are required to be open. By means of these doors the stoker, or fire-man, can at all times regulate the draught of the fire ; for by throwing open the d, e, and at the same time opening the fire-door at a in front, the draught is nearly destroyed, as the cold air passes directly up the chimney without going through the fire ; and by closing the door L, the draught is totally stopped, and the fire soon extinguished. In the centre of the copper a spindle NI is fixed, passing through a tight stuffing box. At the top of the tube E, and above this, it has a cog wheel e, by which the spindle is turned round. On the lower end of the spindle a cross bar is fixed and secured by stays, and short pieces of chain are suspended from it, which drag the bottom of the copper when the spindle is turned round, and stir the hops so as to prevent their burning, which they would do if suffered to rest on the bottom. This apparatus, which is called the rowser, is suspended by a swivel at the top of the spindle, from a lever f, the opposite end of which is drawn down by a rack and pinion This raises the rowser from the bottom of the copper, when it is not in use, and at the same time disengages the wheel e from its pinion, which is kept in continual motion by the engine. Cast iron braces g, g are fixed across the cop per, to support the spindle of the rowser. In the top of the tube E is a safety valve, loaded with a weight h, to permit the escape of the steam, if it should become so strong as to endanger the copper ; and by the side of it is another, i, which opens, and admits air, if a condensa tion of the steam should produce a vacuum in the cop per. The man holes arc closed by lids which are quite steam tight, and can be quickly opened and shut. Their construction is shewn in Figs. 5 and 6 ; the former being a plan, and the other a section. In both of them AA is a ring of cast iron, which, after being turned in a lathe, and ground perfectly flat and true upon its upper surface, is fitted to the copper by a great number of small screws. The door BB is also of cast iron, and has a ring projecting from its under surface to drop into the ring to which the flat surface of the lid is fitted. The lid is hung by a joint D, which is very loosely fitted, and is kept down tight by the pressure of a strong screw a. This screw is held over the centre of it by a cross bar E, fixed to the ring A, by a joint pin at the end j; while the other end slips under a kind of staple. When the central screw is slackened, the bar can be turned about upon its centre); to remove it from the lid, which can then be opened upon the joint D. A balance weight is applied to take oft the weight of the lid, as shewn at Y, Fig. 4.; and within the lid is a smaller one of brass F, Figs. 5 and 6, which is fitted in the same manner ; and which is removed to introduce the ther mometer. or a gauge, for the purpose of ascertaining the quantity of liquor in the copper, without the trouble of moving the great lid, which is only opened to allow men to go into the copper to clean it, while the upper man hole l I is only used to put in the hops. The cop
per is filled by a pipe from the liquor-bac k, as before mentioned. The pipe It, Fig. 2, divides into two branches, each of which is provided with a sluice cock in and a, just before the branches enter the pan from the recess X. The branch in delivers its contents into the pan, but n turns down, and is soldered to the dome of the copper. The pan can be emptied into the copper by two valves p, /i, Fig. 2, in the bottom of it, which are drawn by iron rods and levers reaching over into the recess X. In Fig. 4, T is a sluice cock, to draw off the contents of the copper into a copper vessel Z, from which a pipe runs to the mash tun, as shewn in Plate LXXVII. This pipe has a wire cage set over it, to prevent any thing getting from it into the pipe.
The introduction of the close copper into breweries has led to a great saving of fuel, and has, in some mea sure, prevented the waste of the saccharum and virtue of the hops, which passes off with the steam from the old open copper, as was evident from the strong scent of those substances, which a large one diffused for half a mile round. In the close copper, the steam being passed through the liquor contained in the pan over the copper, the substances alluded to are, in a great degree, condensed and retained in the !Mum., though not per fectly so. At the same time the liquor in the pan is heated, and being let down into the copper as soon as the other liquor has run out of it, it is quickly boiled ; whereas it would have taken much time and fuel if it had been brought into the copper quite cold. We have been informed, that the first pan was placed over the copper, for the purpose of heating one liquor by the other, by Ali. Goodwynne, about 1730; but the steam did not ill this case pass through the water. ltrBrarlah, about 5 years afterwards, built a copper at Harford's brewery, with a dome and steam pipes, as in Plate LXXIX, Fig. 3, except that the pipes F were hung by joints from the great central pipe, so as to rise and fall similar to an umbrella ; and a float being attached to the end of each pipe, the steam always passed out under the same pressure of water, whether the pan was full or not, as the floats always kept the mouths of the pipes at the same depth beneath the surface ; at the same time, this depth could be readily adjusted by altering the floats, so as to increase or diminish at pleasure the pres sure of the steam in the copper. This construction having been found to succeed, has now become com mon.
Ir Richard Hares took out a patent in 1791, for the construction of a steam head to the copper, such as is shewn in Plate LXXIX. Fig. ; but the patent was set aside, by a trial in the court of king's Bench, on the ground of not being a new invention. In the use of a large brewing copper, grpat attention is requisite, in taking care that the copper is never empty whilst the fire is burning ; for in a very few minutes the bottom of an empty copper would be melted by the intensity of the heat. The fire may always be damped, by opening the fire door and the chimney doors immediately. The cock is opened, and the instant the brewer can see the bottom of the copper, he lets down the contents of the pan. For the same reason, it is proper that men should go down into the copper, and scrape away all the fur which adheres to it, from the stony matter contained in the water ; for if that were suff:red to accumulate for a few days, it would prevent the water from coming into actual contact with the copper, which would, in that case, be quickly melted or burnt through. The copper plates are not less than three inches thick in the centre of the bottom, and diminish to one inch thick against the flues. They are united by rivets two inches in diameter, and with heads five inches in diameter. When the copper wants repair, a new plate is put into its place while red hot, and hammered down, to fit the edges of the plates with which it is to be connected. The plate is then heated again, and holes punched through it in the proper places for the rivets, which are put in red hot while the plates arc cold. They are introduced through the holes from the lower side ; and a workman standing upon the grate, has a hand jack, which he screws up under the head of the rivet, to hold it fast in its place, and immediately three men within the copper batter down the end of the rivet with the utmost expedition. In such thick plates, it is almost impossible to get the joints quite close ; but the con traction of the rivets in cooling, draws the plates together so forcibly, as to make them nearly tight, and the leaks cease as soon as the fire is lighted. The very great expence of these repairs, and the loss occasioned by all the works being stopped, render any form of the fire place, which tends to preserve the copper, of very great importance. An improvement in the construction of the lire places was made by Mr Woolfe, who applied it to the coppers at Messrs Meux's brewery, a drawing of which will be found in the Philosophical Magazine, vol. xvii. The description of an apparatus, which this gen tleman erected at the same works for heating water, by the waste steam which passed off from the coppers, was published by Mr Nicholson in his Philosophical Jr.urnal, 8vo. vol. ii.