摘要:
In order to dry boards, the boards are guided on racks through a drier and brought into contact with drying air in two stages. In a stage A with a higher drying power, the drying air is supplied at a higher temperature and with an at least average humidity, and in the other stage B, it is supplied at an average temperature and with a low humidity. The waste heat of the outgoing air from stage A is used for preheating the drying air. This process should reduce the consumption of primary energy. For that purpose, a process is known that consists of also using the outgoing air condensation heat. This has the inconvenience, however, of requiring substantially more secondary energy, as important air mass flows are required to transfer heat because of the low condensation temperature. Primary energy should be reduced by using condensation heat without substantially increasing secondary energy requirements. According to the invention, the outgoing air from stage A is supplied to stage B through a heat exchanger arranged in the rack of the drier. The drying air of stage B is supplied in counter-current through the drier with a low humidity and temperature, so that the boards are dried in stage B both by condensation heat and by radiant heat. Thus only a reduced mass flow of drying air is required to transfer the condensation heat. The consumption of primary and secondary energy is low. This invention is suitable for drying boards as for buildings and gypsum plain boards or fiber boards.
摘要:
In order to dry boards, the boards are guided on racks through a drier and brought into contact with drying air in two stages. In a stage A with a higher drying power, the drying air is supplied at a higher temperature and with an at least average humidity, and in the other stage B, it is supplied at an average temperature and with a low humidity. The waste heat of the outgoing air from stage A is used for preheating the drying air. This process should reduce the consumption of primary energy. For that purpose, a process is known that consists of also using the outgoing air condensation heat. This has the inconvenience, however, of requiring substantially more secondary energy, as important air mass flows are required to transfer heat because of the low condensation temperature. Primary energy should be reduced by using condensation heat without substantially increasing secondary energy requirements. According to the invention, the outgoing air from stage A is supplied to stage B through a heat exchanger arranged in the rack of the drier. The drying air of stage B is supplied in counter-current through the drier with a low humidity and temperature, so that the boards are dried in stage B both by condensation heat and by radiant heat. Thus only a reduced mass flow of drying air is required to transfer the condensation heat. The consumption of primary and secondary energy is low. This invention is suitable for drying boards as for buildings and gypsum plain boards or fibre boards.
摘要:
A drier for broad articles such as plasterboard has a conveyor in entraining the plasterboard along a drying path in a transport plane and the nozzle boxes for contacting the plasterboard with the drying air have their orifice surfaces inclined to the plasterboard to achieve uniformity of drying in terms of residual moisture content.
摘要:
A drying apparatus has a housing, a conveyor for displacing a flat workpiece horizontally in a travel direction through the housing on a level, and a horizontal array of horizontally elongated upper nozzle boxes lying generally in a plane above the level. Each box is formed with a plurality of downwardly directed nozzle holes and heated air is fed to the boxes so it is projected from the holes against the workpiece for drying same. Respective upper shield plates each formed with a plurality of apertures are slidable on the respective boxes between a position with the apertures aligned with at least some of the respective holes and a position with the apertures out of line with the respective holes. At least one pivotal rod extending along a rod axis in the direction has radially projecting arms each engaged with a respective one of the respective shield plates. The rod can be pivoted about the rod axis to shift all the shield plates between their positions.
摘要:
The invention relates to a roller belt drier. The drying of panel-shaped products often requires the drier to have considerable construction lengths in order to achieve a high capacity. Long roller belt dryers, which are usually equipped with chain drives and a motor for each chain, present the problem that very strong chains are required to transmit the necessary driving forces. When the drier reaches a certain length, it is no longer possible to provide chains that are able to accommodate these forces. According to known solutions, a chain is divided and the drives are located in the centre of the drier. This causes problem s in terms of sealing the drier, as well as extra expense for the driving and tension station. The aim of the invention is to create a drier which has a driving and tension system that is structurally simple and economical even for considerable construction lengths. A chain is equipped with two drives (15, 23), the second drive (23) being integrated in a tension device (24). The invention is suitable for drying panel-shaped goods, especially plaster boards or plaster fibre boards.
摘要:
An isocyanate-terminated prepolymer C having an NCO content of from ≧26% by mass to ≦31.0% by mass is obtainable from the reaction of an isocyanate composition A having a viscosity at 25° C. of from ≧60 mPas to ≦800 mPas, comprising from ≧25% by mass to ≦60% by mass MDI and from ≧40% by mass to ≦75% by mass pMDI, wherein the sum of the amounts of those components is ≦100% by mass, with a bifunctional polyester ether polyol B having an OH number of ≧200 mg(KOH)/g and ≦500 mg(KOH)/g, obtained from the reaction of a dicarboxylic acid/dicarboxylic acid derivative with at least one polyol and with an epoxide, wherein the polyester ether polyol B is used in amounts of from ≧1.5% by mass to ≦6.0% by mass, based on the sum of the masses of A and B. The invention further provides a PUR/PIR polymer produced from the prepolymer C, its use and composite elements based thereon.
摘要:
A measuring device and method according to the invention for registering an ambient temperature Ta of a medical machine including a measuring housing, which is arranged on an outer wall of the machine and in which at least one temperature sensor remote from the machine and at least one temperature sensor (16, 16′) near to the machine are held, wherein the at least one temperature sensor remote from the machine registers a first temperature T1 and the at least one temperature sensor near to the machine registers a second temperature T2, and an evaluation apparatus configured to establish the ambient temperature Ta using a difference between the first temperature T1 registered by the at least one temperature sensor remote from the machine and the second temperature T2 registered by the at least one temperature sensor near to the machine.
摘要:
A process for the preparation of polyricinoleic acid esters comprising the step of reaction of ricinoleic acid with an alcohol component which comprises mono- and/or polyfunctional alcohols having a molecular weight of ≧32 g/mol to ≦40 g/mol, wherein the reaction is carried out at least partly in the presence of a catalyst. The amount of catalyst, based on the total weight of the ricinoleic acid and the alcohol component, is in a range of from ≧10 ppm to ≦100 ppm. The reaction is ended when the acid number of the reaction product obtained is ≧5 mg of KOH/g to ≦100 mg of KOH/g. The invention furthermore relates to a polyurethane polymer, in particular a flexible polyurethane foam, which is obtainable using these polyricinoleic acid esters.
摘要:
Isocyanate mixtures comprising: (a) NCO prepolymers having an NCO content of 1.5 to 18 wt. %; and (b) 1 to 40 wt. % of monomeric 2,2′-diisocyanatodiphenylmethane, based on the isocyanate mixture; wherein the isocyanate mixture has a total NCO content of from 2 to 22 wt. %; polyisocyanate polyaddition products prepared therefrom; and methods of making the same.
摘要:
The present invention provides improved variants of T7 RNA polymerase by introducing novel mutations which lead to improved thermostability of the enzyme. According to the invention, amino acid substitutions at the positions Val426, Ser633, Val650, Thr654, Ala702, Val795, and combinations thereof are advantageous.