摘要:
A belt pressure filter comprises a gravity dewatering zone for dewatering a sludge as a function of the gravity and a forced dewatering zone for a forced dewatering of the sludge by means of external pressure. An endless filter belt travels from the gravity dewatering zone to the forced dewatering zone. The coagulated sludge is supplied onto the filter belt by means of the gravity dewatering zone. Information representing the level of the sludge deposited on the belt is obtained as an information concerning the dewatering ability of the coagulated sludge supplied onto the filter belt. The traveling speed of the filter belt is calculated and controlled on the basis of the above described level information which represents the layer thickness and hence also the solids concentration. The optimum amount of a dosage of a coagulating agent is determined based on the traveling speed of the filter belt as calculated. As a result, the water content in a dewatered cake is maintained low and constant, while an optimal amount of coagulating agent most suited to the sludge characteristics at that time is added to the material without wasting any excess coagulating agent.
摘要:
Apparatus is disclosed for steam drying filter cake formed on a drum or disc vacuum filter mounted for rotation in a container the lower portion of which comprises a feed slurry tank and the upper portion comprises a steam hood or steam dome. Means are provided to control the distribution of steam to the dome; to provide releasable seals for the rotary filter; to provide an improved steam hood; to provide exhaust means for the device and to provide an air cooler for the formed and heated filter cake.
摘要:
A method of manufacturing polyimide particles, including: combining a polyimide solution including a polyimide and an organic solvent with an aqueous solution including water in the presence of an emulsifying surfactant at a shear rate from 1,000 to 3,000 revolutions per minute, from 1,000 to 2,500 revolutions per minute, or from 1,500 to less than 2,500 revolutions per minute to form an emulsion; removing the organic solvent to form an aqueous polymer dispersion including polyimide particles; and recovering the polyimide particles, which have a spherical morphology, and a volume based D10 diameter from 3 to 50 micrometers, preferably from 3 to 45 micrometers and a volume based D90 diameter from 3 to 80 micrometers, from 3 to 75 micrometers, or from 3 to 45 micrometers and a volume based D100 diameter from 3 to 100 micrometers, from 3 to 75 micrometers, or from 10 to 75 micrometers.
摘要:
Apparatus is disclosed for dewatering aqueous suspensions including a pair of rotatable rolls forming a nip therebetween, so that the aqueous suspension can pass downwardly through the nip and be dewatered by removing a filtrate from the suspension, and the dewatered suspension can pass downwardly from the nip, at least one of the rolls being liquid permeable, and at least one screen adjacent to the roll and disposed below the nip, the screen is separated from the roll by a predetermined distance and extends along its length, the predetermined distance being a sufficient distance so that a film of filtrate on the roll passes between the roll and upper end of the screen on one side of the screen and the dewatered suspension passes on the other side of the screen so that the filtrate is prevented from contacting the dewatered suspension below the nip.
摘要:
Disclosed herein are a method for removing liquid from a permeable material, such as slurries, sludges, porous solids and permeable foams. The method involves constraining the material to be deliquified such that the material interfaces with at least one surface which is permeable to the liquid to be removed and then heating the material at one or more locations remote from the permeable surface or surfaces. Such constraining and heating of the material causes the in situ vaporization of the liquid in the vicinity of the remote location or locations. The vaporized liquid expands and forces at least some of the remaining unvaporized liquid through the permeable surface or surfaces. Because only a portion of the liquid contained in the material must be vaporized and such vaporized portion is used to remove at least some of the remaining unvaporized liquid (thereby avoiding the necessity of vaporizing all of the liquid containing in the material), significant reductions in the energy required to substantially deliquify the material may be realized through the use of the method disclosed herein.
摘要:
A method for dewatering a slurry of solid particles suspended in a liquid using a twin belt press dewatering system, comprising the following steps:feeding the slurry of solid particles into the dewatering system;feeding a cationic amine salt solution into the dewatering system at a point just prior to the mixing drum, the cationic amine salt being a latex copolymer of acrylamide and dimethylaminoethylmethacrylate sulfuric acid salt having a mole ratio in the range between about 30:70 to 70:30, preferably 53:47;mixing the cationic amine salt solution with the slurry of solid particles in the mixing drum; andfeeding the cationic amine salt solution/slurry mixture to the twin belt press, whereby the slurry of solid particles is dewatered. The cationic amine salt solution having a strength of less than 1% and a polymer concentration of about 35%.
摘要:
A method is disclosed for steam drying filter cake on a drum or disc type vacuum filter having a steam drying cycle wherein optimum cake thickness and moisture content is obtained at optimum thermal efficiency by controlling the vacuum during cake formation and controlling the filtration rate by control of the speed of rotation of the filter element.