摘要:
Apparatus for thickening a suspension of pulp material employs a single pair of liquid-impervious rolls and a single loop of wire trained around both rolls which are spaced from each other in substantially the same horizontal plane. The pulp stock to be thickened is delivered into the wedge zone defined by the upper wire run approaching the top of one roll and the surface of that roll, so that the pulp is trapped between the wire and roll as it travels around the roll with the wire, and the rolls are driven at sufficient speed to develop centrifugal forces which cause liquid to be expressed through the wire from the pulp trapped against the roll. The resulting partially dewatered pulp is redeposited from the first roll onto the lower wire run for travel to the other roll, where it is similarly subjected to centrifugal force for further expression of liquid through the wire, after which the pulp is removed from the surface of the second roll in the wedge zone defined by the surface of that roll and the wire run travelling therefrom to the first roll.
摘要:
Wheel-mounted brake disks which are arranged on both sides of a wheel base of a railway wheel and are fastened by through bolts, the bolt head of every through bolt lying in a countersink of one wheel-mounted brake disk and a nut screwed onto the through bolt lying in a countersink of the other wheel-mounted brake disk, each resting either directly or indirectly on the bottom of the countersink. The wheel-mounted brake disks are designed so that every countersink has an undercut portion that extends down to the bottom.
摘要:
Embodiments of apparatus for thickening a liquid suspension of solid particles, such as papermaking pulp in water, include a pair of spaced apart rolls and a woven wire or plastic wire belt trained around these rolls. The suspension is supplied to the apparatus at the first roll for centrifugal extraction and is carried by the belt to the second roll for further water extraction and thickening, and is then discharged from the apparatus. In one embodiment, the first roll is formed with an open surface, and the suspension is delivered to the web at least partially by flowing through the first roll openings, from either a headbox in the on-running wedge zone or a headbox internal to the rolls to deliver stock outwardly through the roll. The apparatus may also include a second roll which is porous and has auxiliary water-removing appliances associated therewith, including blow boxes for forcing air either radially inwardly or radially outwardly of the second roll, and an auxiliary nip roll for creating a zone of higher compression for mechanical extraction of water from the mat of solid particles between the belt and the second roll. Rewetting of the mat caused by water entrained in the wire mesh cavities is reduced by the impingement of air jets to remove such water. In a further embodiment, one or both rolls may include a pair of disks spaced apart on a support shaft with the wire belt trained over the outer surfaces of the disks so that a substantial open extent of the belt is defined between the disks. The rolls may be mounted with the plane defined by their axes in any desired spatial orientation, from horizontal to vertical.
摘要:
A deflection controlled roll has a rotatable shell supported on a non-rotating central beam by a plurality of individual shoes which are positioned transversely of the beam between the beam and the shell. A curved semicylindrical surface of the shoe bears against an inside surface of the shell and is hydrodynamically lubricated by an oil film, in the nature of a plain bearing. The shoes are biased by inflatable air lift bellows which are positioned within recesses within the shoe, between the shoe and the beam. The shoes are mounted on the beam on pins which provide at least three degrees of freedom of movement. An improved drive for the roll shell has a cog belt sheave mounted on the shell in concentric relation to one of the shell support bearings. A cog-type drive belt is threaded on the sheave, and a drive pulley for the drive belt is positioned normal to the direction of shell deflection such that the deflections do not change the spacing between the pulley and the sheave.
摘要:
A solution of a polyurethane in a polyol is made from (a) the reaction product of a polyisocyanate and a diprimary diol, and (b) a polyether in which the reaction product constitutes from 3 to 60 wt. % of the solution. Suitable diprimary diols have a molecular weight of from 90 to 800 and a structure at both hydroxyl groups corresponding to the general formula: ##STR1## in which R.sub.1 represents chlorine, an alkyl, cycloalkyl, aralkyl or aryl radical having from 1 to 10 carbon atoms, which carbon atoms may be substituted or interrupted by chlorine, ester groups, ether groups, amide groups, urethane groups or nitrile groups, andR.sub.2 represents hydrogen or a radical within the definition of R.sub.1.Polyethers which may be employed have at least two hydroxyl groups (at least 80% of which are secondary hydroxyl groups) and an average molecular weight of from 500 to 12,000. The disclosed solutions are particularly useful in the production of flexible polyurethane plastics which are suitable for flamecoating and high frequency bonding.
摘要:
The present invention relates to a process for the preparation of polyurethane foams capable of being flame laminated and high frequency welded, comprising reacting:(a) polyisocyanate,(b) a compound having a molecular weight of from 400 to 10,000 containing at least two isocyanate-reactive hydrogen atoms and(c) a dialkoxy-phosphonyl-N-alkyl-formic acid amide of the formula: ##STR1## wherein m represents an integer of from 1 to 3,n represents an integer of from 0 to 8,X represents halogen, hydrogen, C.sub.1 to C.sub.6 alkyl, --OR, or ##STR2## R represents C.sub.1 to C.sub.6 alkyl, R.sub.1 represents hydrogen, C.sub.1 to C.sub.10 alkyl, C.sub.1 to C.sub.10 alkylene, C.sub.6 to C.sub.10 aryl or C.sub.6 to C.sub.10 arylene, andR.sub.2 and R.sub.3, which may be the same or different, represent C.sub.1 to C.sub.10 alkyl in the presence of water and/or blowing agent.The present invention also relates to dialkoxy-phosphonyl-N-formic acid amides.
摘要:
A system and method for separating paper fibers from contaminants of lower specific gravities employ a reverse centrifugal cleaner wherein the inlet port is of substantially greater flow area than previously used or proposed for either normal or reverse centrifugal cleaning, each of the apex and base ports are of greater flow area than the inlet port, and the discharge flows are controlled to provide an accepts flow through the apex port which is less than the reject flow through the base port. The system provides substantial advantages over prior practice, particularly in the areas of both capital and operating costs, capacity, and cleaning efficiency in terms of the energy requirements for given tonnage of accepted fiber.
摘要:
A waste treatment system which is capable of handling materials of widely different physical characteristics such as glass, metal, and fibrous and plastic waste, incorporates a rotor rotatably mounted in a waste receiving vessel, the rotor being adapted to fracture brittle material, compact malleable material, and otherwise pulverize the frangible waste to a particulate form small enough to be extracted through a perforated plate. The rotor also circulates the material in a slurry form within the vessel in a vortical pattern so that the waste is repeatedly treated until it is ejected from the vessel. A series of space attrition bars are mounted outwardly of the rotor to provide an annularly shaped, discontinuous attrition surface, and hammers or flails are pivotally mounted on the rotor to reduce into smaller pieces materials which are flung upon or between the attrition bars by the rotor. Where the waste material contains a high proportion of rags, tubing and other stringy material, a rotating chopper blade is provided to chop this portion of the waste into smaller pieces which are more readily handled by the rotor and flails. Waste materials which are not readily reduced to a pulverized state by the system are segregated from those which are and removed separately.
摘要:
Compositions that include a mixture of three different ethoxylated alcohols with or without further products are useful for pretreating textile materials, especially cotton fabrics. The compositions have acceptable viscosities and are preferably used in the form of aqueous solutions or dispersions. These have little if any tendency to form foam, are highly compatible with enzymes and impart very good rewettability to textiles treated therewith.
摘要:
Compositions which, as well as water, contain certain sulfonate salts or polyhydric alcohols together with ethoxylated/propoxylated alcohols and ethoxylated alcohols are useful for pretreating textile sheet materials. Further ingredients also render them useful for hydrogen peroxide bleaching. The compositions, which provide the textiles with good primary wettability and good rewettability, are low-foaming. Batchwise pretreatment processes, for example in jet machines, therefore represent no problem.