摘要:
The invention concerns a vacuum lifter to transport loads with an adhesion surface, comprising at least one suction head suspended from a hoist, said suction comprising at least one annular seal projecting from its suction side, the vacuum chamber(s) enclosed by the annular seal(s) communicating with a vacuum source, a valve furthermore being provided which can be switched between a suction position wherein the vacuum source communicates with the pressure chamber or vacuum chambers and a venting position wherein the communication with the vacuum source is interrupted and the vacuum chamber(s) is (are) vented or fed with compressed air. To assure venting or compressed-air supply immediately upon deposition of the load, the hoist is connected by a fitting 55 to the suction plate 5, said fitting being guided in vertically displaceable manner between two end positions, a sensor or a limit switch 59 being provided to detect the lower end position of the fitting 55 and so cooperating with a control means that following lowering of the fitting 55, the valve 20 shall be switched into the venting position if previously having been in the suction position.
摘要:
2-(4-Isobutylphenyl)-propionic acid is purified by subjecting it to a vacuum rectification, in which the temperature is below the decomposition temperature of the acid.
摘要:
This invention relates to thermostable thermoplastic moulding compounds consisting of a thermoplastic aromatic polycarbonate resin, a graft polymer and optionally a thermoplastic vinyl polymer wherein the graft or vinyl polymer is emulsion polymerized with an emulsifier which is the reaction product of 2 mols of certain carboxylic anhydrides and 1 mole of certain diols.
摘要:
The invention relates to 2-phosphonobutane-1,2,4-tricarboxylic acid derivatives, which can be obtained by reaction of the tricarboxylic acid with C.sub.6-20 -alcohols and which are suitable as auxiliaries (emulsifiers) for emulsion polymerization.
摘要:
An emulsifier for the preparation of polymers comprising more than 50 percent by weight of an alkali metal salt of polysulphonic acid of alkane of medium chain length is disclosed. The emulsifier is useful in forming emulsions of polymers especially thermoplastic polymers and in particular polymers of vinyl chloride. It is useful in vinyl chloride polymerization and co-polymerization to form an emulsifier composition having improved transparent and antistatic properties. The polymer can be added before, during or after polymerization. When added after polymerization it provides improved properties to a calendered object obtained from the polymer.
摘要:
Brine (an aqueous solution of alkali metal chlorine) which is electrolyzed according to the amalgamation process, generally contains small amounts of mercury. It has been found that these traces of mercury are entrained with the evaporated water in a considerable amount when applying evaporation cooling to the brine. In order to keep these losses as low as possible, a pH of from 7 to 9.0 and a redox potential more than 1391-6.66(pH)-5.94(pH).sup.2 but not more than 1100 mV (based on the potential of the hydrogen electrode) is adjusted by adding chlorine or alkali metal hypochlorite and optionally alkali metal hydroxide to the brine.
摘要:
This invention relates to graft polymers of the ABS type which are produced in emulsion, and to thermoplastic molding compositions which are based thereon and which exhibit a very considerably increased notched bar impact strength compared with known ABS molding compositions and which at the same time exhibit high hardness values or high modulus values and good thermoplastic processability.
摘要:
A vacuum lifter for a moving load having an adhesion surface comprising at least one suction head having several annular seals projecting from its suction side and forming vacuum spaces enclosed by the seals. The vacuum spaces communicate with a vacuum source. The vacuum source communicates through valves with the outer vacuum space. The valves are controlled by sensors detecting the magnitude of the adhesion surface of the load. In order to prevent impulsive detachment and especially unwanted renewed lifting of the load after it has been deposited, a compressed-air system associated with at least one of the vacuum spaces and a control system turns ON and OFF the compressed-air system in order to initially raise the pressure to atmospheric and to thereafter generate a positive pressure air cushion separating the lifter from the load.
摘要:
The invention concerns a vacuum lifter to transport loads with an adhesion surface and comprises at least one suction head with at least one projecting annular seal on its suction side, where the vacuum chamber(s) enclosed by the annular seal(s) is (are) hooked up to a main vacuum source and where additionally a battery-fed emergency vacuum source is provided which can be started by an emergency switch. In order to avert as much as possible crashes when using such a vacuum lifter, a pressure pickup (67) is associated with the or at least one of the vacuum chambers (13) and is coupled in such a way with a malfunction alarm (69) that when a preset limit pressure is exceeded during vacuum operation, the malfunction alarm (69) shall be turned ON.
摘要:
A process for separating m- and p-dichlorobenzene by extractive rectification with an extractant and removal of this extractant. Using as extractant an alkylene carbonate of the formula ##STR1## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are identical to or different from one another and each is hydrogen, methyl or ethyl, with the proviso that together the radicals R.sup.1 to R.sup.4 do not contain more than 6 carbon atoms.The process of the invention makes it possible to separate off the m-isomer in high purity.