Abstract: A method of sealing cavities open on one side, preferably cavities of electrical equipment housings fitted with various components. A measured quantity of an encapsulant, preferably polyurethane foam, is inserted into the cavity. Thereafter the opening is covered by a permeable, absorbent fabric, preferably of polypropylene, which is covered first by an elastic and then a rigid layer. After hardening, the fabric is removed from the surface of the encapsulant.

Abstract: There is produced a stabile per salt which contains simultaneously sodium percarbonate and sodium perborate by introducing a solution supersaturated with both sodium percarbonate and sodium perborate to nuclei which consist of sodium percarbonate and/or sodium perborate.

Abstract: There are prepared sodium percarbonate particles comprising a sodium percarbonate nucleus encased in a layer of a mixture of dehydrated sodium perborate and sodium silicate prepared by spraying the sodium percarbonate with a supersaturated solution of sodium perborate and a sodium silicate solution and drying to at least partially remove the added water.

Abstract: There are prepared sodium percarbonate particles comprising a sodium percarbonate nucleus encased in a layer of dehydrated sodium perborate or a mixture of dehydrated sodium perborate and sodium silicate with or without additional water binding materials chemically inert to sodium percarbonate and dehydrated sodium perborate.

Abstract: There are prepared sodium percarbonate particles consisting essentially of a sodium percarbonate nucleus encased in a layer of sodium silicate and sodium percarbonate and/or sodium tripolyphosphate.

Abstract: A compact, abrasion resistant sodium percarbonate is produced by reacting sodium carbonate with hydrogen peroxide. There is employed a solution saturated in sodium percarbonate and also containing (1) sufficient sodium carbonate that there is present sodium carbonate decahydrate as a solid phase, (2) sodium chloride in an amount of 100 to 200 grams per liter, (3) an active oxygen stabilizer and (4) sodium hexametaphosphate in an amount of 0.1 to 1.9 grams per liter. There is added hydrogen peroxide in an amount about equivalent to the dissolved sodium carbonate which results in a supersaturated solution of sodium percarbonate. The supersaturation is broken down by precipitation of sodium percarbonate during the addition of the hydrogen peroxide and up to 60 minutes thereafter. The entire process is carried out at a substantially constant temperature within the range of 10.degree. to 20.degree. C.

Abstract: A compact, abrasion resistant sodium percarbonate is produced continuously by reacting sodium carbonate and hydrogen peroxide in the presence of sodium percarbonate inocculant seeds, sodium chloride, an active oxygen stabilizer and sodium hexametaphosphate at 10-20.degree. C, the process comprises feeding into the preliminary inocculant and aqueous hydrogen peroxide solution containing an active oxygen stabilizer and simultaneously either (1) a filtered solution saturated in sodium carbonate and containing 40-100 grams per liter of sodium percarbonate, 0.1-1.0 gram of sodium hexametaphosphate per liter, 100-200 grams of sodium chloride per liter and an active oxygen stabilizer or (2) a mother liquor containing 40-100 grams of sodium percarbonate per liter, 0.1-1.

Abstract: Abrasion resistant and coarser sodium perborate tetrahydrate is prepared by reacting an aqueous sodium metaborate solution with aqueous hydrogen peroxide while avoiding free active oxygen and free alkali in the reaction medium. A strongly supersaturated perborate tetrahydrate solution having 200 to 700 grams/liter of perborate tetrahydrate is introduced into a previously prepared suspension of mother liquor and innoculant crystals which contains 100 to 500 grams/liter of suspension of seed crystals at such a rate that not more than 30 grams of perborate tetrahydrate grow as crystals per minute per square meter apparent innoculant surface area at 20 to 40.degree. C. and a rate of crystallization growth of not more than 100% whereupon the temperature is reduced to 15.degree. C. within 15 to 30 minutes, in a given case in a subsequent step. In another aspect of the invention the perborate is added at a point not earlier than the crystallizer.