boiler and pipe covering - boiler and pipe covering; boiler and pipe covering - See also silicate cotton or slag-wool.
Take a bushel of fire-clay, a bushel of common clay, a bushel of cow dung, 3 pints of tar, a peck of fine ashes, and a small quantity of plasterer's hair. Moisten with water and mix to the consistency of mortar. The following is the method of application (The method here described has to be followed with nearly all compositions of the kind). First heat the boiler or pipe surface to about 120 ° F., then with the hand or a cloth, or a suitable brush, rub a thin coat of the mixture on to the boiler. The object of this is to get the material to adhere. When this is done (and left rough, not smoothed), the first coat can be put on. This is applied with a trowel and should not be more than ½ in. to ¾ in. thick. Let it be very roughly finished, to make a key for the next coat, and let it stand one day to dry. Moisten the dried surface with water or some of the mixture diluted to a wash and apply the second coat, leaving this rough, as the last, and allowing it a day to dry. Repeat the process for the last coat, but this can be trowelled smooth. The three coats should make at least 2 in. thick, while in certain cases four coats and a total thickness of 3 in. are needed. In certain cases, plaster is mixed with the last coat so as to admit of a good finish with the trowel. If there is any likelihood of the covering being knocked or roughly used, it can have a final covering of damp canvas put on while the last coat of composition is soft. When dry the canvas is painted. In some cases fine wire netting is put over the covering, With pipes of moderate size, the canvas covering, if used, is cut into strips. 6 in. wide, and wound on spirally.
Take 6 parts sifted coal ashes, 4 parts fire-clay, 1 part common clay, 2 parts plaster of Paris, 1 part of flour, 2 parts cow dung, clear of straw, 2 parts cow-hair, 1/5 part of coal tar, and mix altogether to the consistency of mortar, using what water is necessary for this. Apply exactly the same as with the preceding recipe (a).
5 cwt. of fossil meal (f Also known as " Kieselguhr."), 5 cwt. fine road dust, 5 cwt. cow dung, 1 cwt. fire-clay in powder, about a bushel of finely cut chaff, 4 lb. well separated cow-hair. This, when well mixed, can be stored dry and when required for use moistened with water to the consistency of mortar. A rather special feature with this, as with all similar mixtures is that well working it in the moist state tends to toughen and improve it. Apply this mixture as described with the first recipe (a).
A mass highly recommended is prepared as follows: 100 parts by weight of finely ground limestone, 350 of finely ground coal, 250 of pulverised clay, 300 of fine ashes from boiler-flues are thoroughly mixed with 600 of water and 10 of sulphuric acid of 50 °Be., and after adding 15 of hair (cow-hair or calf-hair) the whole is made as homogeneous as possible. The article to be covered should, if possible, be previously heated. The mass is then gradually applied in separate layers, each about ¾ in. thick, until a thickness of 2 to 2¾ in. is attained. The whole may finally be painted any colour desired.
Boil 1 lb. each of rice flour, rye flour, cows' hair and treacle with 150 qt. of water, and gradually and with constant stirring add 80 lb. of infusorial earth or fossil-meal. Apply the mass in several layers to the lukewarm pipes.
Waste of cork, asbestos, gypsum and cement, all finely ground, are, shortly before use, made with water into a paste of the consistency of mortar. The resulting mass is applied with a trowel to the objects to be insulated. It answers the purpose far better than masses containing hair, glue, treacle, etc., as it is not subject to putrefaction or fermentation, nor destroyed by heat. It being a very poor conductor of heat the highest useful effect can be attained; it adheres well and is very durable.
Felt, cork waste, mineral wool either made into suitable forms and attached to the pipe, or filled into a casting surrounding the pipe, and with or without an air space about the pipe, are much used for the above purpose.