Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Patent
1993-10-26
1995-01-31
Schofer, Joseph L.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
526 86, C08F 214
Patent
active
053859928
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method for the dosage of a fluidized polymerization catalyst into a polymerization reactor.
A requirement of the dosage pump of a fluid substance is that its dosage accuracy is as great as possible simultaneously as it is retaining its reliability of operation. A pump of the above-mentioned type is disclosed in FI patent specification 65127, wherein a double cylinder pump with valves installed in the inlet and outlet openings of the piston-swept space has been used for the synchronized feed of two substances. It has been thought that one of the pump chambers is feeding wax intended for the burnishing of cars.
When feeding by a dosage pump hard flowing material, such as wax or slurry, the combining of the dosage accuracy with the reliability of operation becomes difficult. The dosage accuracy suffers if the hard flowing substance slows down or prevents the cooperation of the valves of the inlet and outlet openings in the piston-swept space of the cylinder chamber. The valves can also be clogged or they can become out of order due to the high pressure used in the tube system.
The drawback of the dosage pump according to the above-mentioned FI patent specification 65127 is, in fact, that the conventional valves of inlet and outlet openings do not operate faultlessly when hard flowing wax is used.
Pumps of the same type are presented e.g. in the publications DE 230,710; 248,634; and 329,400. Of these publications DE publication 248,634 presents a valveless suction and force pump, to the solid pump cylinder (1) of which a cylinder liner (2) has been arranged comprising openings (9 and 12) corresponding to the inlet and outlet openings (25 and 25) of the pump cylinder (1), which at the rotation of the cylinder liner (2) alternatively open and close the inlet and outlet openings.
For the same reason the feeding of solid coordination polymerization catalyst into the polymerization reactor has proven very problematic. The condition for a stabile polymerization process and a good polymerization product is an accurate and undisturbed catalyst feeding system. Many companies have patented catalyst feeding systems. So, FI 68630 WO 85/02851 discloses a method and a device for adding continuously pulverous coordination catalyst into a pressurized reactor. In the method a mixture of the catalysator and a wax, such as a polyethene wax, is pumped by means of an inert medium, such as heptane, into the polymerization reactor. The dosage problem has thus been solved by using a medium decreasing the hard flowability. When decreasing the viscosity the danger is, however, the separation of the solid and heavy catalyst, which results in a bad dosage accuracy.
The present invention concerns with the provision of a dosage method for a fluid substance having a great dosage accuracy and reliability of operation, particularly when dosing hard flowing substance. The invention is, furthermore, concerned with the provision of a method for dosing of a coordination catalyst into an olefin polymerization reactor, particularly a pressurized reactor. These aims have now been achieved by the new method for the dosing fluid substance, which is principally characterized by what is stated in the characterizing clause of claim 1.
Thus, it has been realized that the dosage pump can be provided with a freely travelling and tightly between the inner mantle surface of the cylinder and the outer mantle surface of the piston arranged intermediate pipe having a transmission opening adjustable upon the inlet and outlet opening of the piston-swept space. According to the new method the opening and closing of the inlet and outlet openings in the piston-swept space of the cylinder is carried out by freely rotating the intermediate pipe mentioned so that its transmission opening overlaps either the inlet or the outlet opening, whereby the whole surface of the intermediate pipe always covers either one of the inlet and outlet openings.
The invention is thus related to a new kind of dosage pump comprising a cylinder, a back and forth mo
REFERENCES:
Response to Written Opinion of International Preliminary Exam Report, dated May 3, 1993.
International Search Report, Revised Version, dated Jun. 29, 1992.
International Preliminary Exam Report, dated Jun. 22, 1992.
Copy of Written Opinion from International Preliminary Exam Authority, dated Mar. 29, 1993.
Koskinen Jukka
Leskinen Pauli
Nyfors Klaus
Borealis Holding A/S
Schofer Joseph L.
Weber Tom
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