Stirrer and cover for stirring corrosive charges

Claim 2

IN A STIRRING CORROSIVE CHARGES IN CORROSION RESISTANT, HIGH PRESSURE REACTION TANKS, SUCH AS GLASS-LINED TANKS, THE STIRRER INCLUDING A METALLIC STIRRING SHAFT AND A PLASTIC STIRRING ELEMENT ATTACHED TO ONE END OF THE STIRRING SHAFT, SAID STIRRING ELEMENT BEING DRIVEN BY SAID STIRRING SHAFT, THE STIRRING ELEMENT BEING FAFABRICATED AS A ONE-PIECE ELEMENT HAVING A PLURALITY OF ARMS, THE IMPROVEMENT COMPRISING: A PLASTIC COVER COVERING A PORTION OF THE STIRRING SHAFT WHICH CONTACTS THE CORROSIVE CHARGE, SAID COVER HAVING TWO END PORTIONS WITH ONE END PORTION BEING SEALINGLY SECURED TO THE STIRRING ELEMENT AND THE OTHER END PORTION BEING SEALINGLY SECURED TO THE STIRRING SHAFT WHEREIN SAID COVER HAS AN INTERMEDIATE PORTION BETWEEN ITS SECURED END PORTIONS WHICH IS MOVABLE RELATIVE TO SAID END PORTIONS, AND WHEREIN SAID COVER IS FABRICATED SO THAT AT LEAST PART OF ITS LENGTH BETWEEN ITS SECURED ENDS IS RESILIENT

Claim 3

In a stirrer for stirring corrosive charges in corrosion resistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a metallic stirring shaft and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover being fabricated as an extruded pipe and having two end portions with one end portion being sealingly secured to the stirring element and the other end portion being sealingly secured to the stirring shaft.

Claim 4

In a stirrer for stirring corrosive charges in corrosion resistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a metallic stirring shaft and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover being fabricated as an extruded pipe and having two end portions with one end portion being sealingly secured to the stirring element and the other end portion being sealingly secured to the stirring shaft.

Claim 5

In a stirrer for stirring corrosive charges in corrosion resistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a metallic stirring shaft having a frusto-conical portion and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover having two end portions with one end portion being sealingly secured to the stirring element and the other end portion being sealingly secured to the stirring shaft; a screw cap which threadedly engages said stirring shaft, said screw cap having a surface which is generally parellel to the outer surface of said frusto-conical portion, said threaded engagement being such that said one end portion of said cover can be received and secured between said surfaces.

Claim 6

In a stirrer for stirring corrosive charges in corrosion resistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a metallic stirring shaft having a frusto-conical portion and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover having two end portions with one end portion being sealingly secured to the stirring element and the other end portion being sealingly secured to the stirring shaft; a screw cap which threadedly engages said stirring shaft, said screw cap having a surface which is generally parellel to the outer surface of said frusto-conical portion, said threaded engagement being such that said one end portion of said cover can be received and secured between said surfaces.

Claim 7

In a stirrer for stirring corrosive charges in corrosion resistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a metallic stirring shaft and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover having two end portions with one end portion being sealingly secured to the stirring element and the other end portion being sealingly secured to the stirring shaft, wherein the diameter of said stirring shaft along the portion thereof which is covered by said cover and is in the area of the corrosive charge is larger than the diameter of said stirring shaft along the portion thereof which is not covered by said cover.

Claim 8

In a stirrer for stirring corrosive charges in corrosion resistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a metallic stirring shaft and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover having two end portions with one end portion being sealingly secured to the stirring element and the other end portion being sealingly secured to the stirring shaft, wherein the diameter of said stirring shaft along the portion thereof which is covered by said cover and is in the area of the corrosive charge is larger than the diameter of said stirring shaft along the portion thereof which is not covered by said cover.

Claim 9

A stirrer as defined in claim 4, wherein the larger diameter portion of said stirring shaft includes an end seal and a metallic weld member, said end seal having a recess for receiving and having welded therein one end of said weld member, and wherein said end seal includes a frusto-conical sealing portion and a torque transmitting extension.

Claim 10

In a stirrer for stirring corrosive charges in corrosion reSistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a metallic stirring shaft and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover having two end portions with one end portions with one end portion being sealingly secured to the stirring element and the other end portion being sealingly secured to the stirring shaft; a tie rod; and a holding mechanism, said tie rod being adapted to attach said stirring shaft to said stirring element and said holding mechanism being adapted to effect said attachement, wherein said stirring element includes a bore defining hub portion at its center, and said stirring shaft includes an end seal having a frusto-conical sealing portion and a torque transmitting extension, and wherein said bore is configured to define a first portion having a surface which is generally parallel to the outer surface of said frusto-conical portion and defining a receiving space for said frusto-conical portion, a second portion defining a receiving space for said torque transmitting extension and a third portion defining an abutment surface for said holding mechanism.

Claim 11

In a stirrer for stirring corrosive charges in corrosion reSistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a metallic stirring shaft and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover having two end portions with one end portions with one end portion being sealingly secured to the stirring element and the other end portion being sealingly secured to the stirring shaft; a tie rod; and a holding mechanism, said tie rod being adapted to attach said stirring shaft to said stirring element and said holding mechanism being adapted to effect said attachement, wherein said stirring element includes a bore defining hub portion at its center, and said stirring shaft includes an end seal having a frusto-conical sealing portion and a torque transmitting extension, and wherein said bore is configured to define a first portion having a surface which is generally parallel to the outer surface of said frusto-conical portion and defining a receiving space for said frusto-conical portion, a second portion defining a receiving space for said torque transmitting extension and a third portion defining an abutment surface for said holding mechanism.

Claim 12

A stirrer as defined in claim 6, wherein said holding mechanism comprises: a mounting plate having a central threaded bore within which said tie rod is threadedly received and a plurality of bolt receiving bores, said plate being adapted for reception within said second bore portion; and a plurality of adjustable abutment elements, each being rotatably mounted by a bolt to said plate at a respective one of said bolt receiving bores, and each being positioned relative to said plate so that said plate can be received into said second bore portion and thereafter each is positioned within said third bore portion and in engagement with said abutment surface.

Claim 13

In a stirrer for stirring corrosive charges in corrosion resistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a hollow metallic stirring shaft and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a hub portion and a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover having two end portions with one end portion being sealingly secured to the stirring element and the other end portion being sealingly secured to the stirring shaft; a tie rod which passes through said hollow stirring shaft; and means mounting said tie rod within said hub portion to said stirring element to thereby clamp together said cover, said stirring shaft and said stirring element and effect one of the secured ends of said cover.

Claim 14

In a stirrer for stirring corrosive charges in corrosion resistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a hollow metallic stirring shaft and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a hub portion and a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover having two end portions with one end portion being sealingly secured to the stirring element and the other end portion being sealingly secured to the stirring shaft; a tie rod which passes through said hollow stirring shaft; and means mounting said tie rod within said hub portion to said stirring element to thereby clamp together said cover, said stirring shaft and said stirring element and effect one of the secured ends of said cover.

Claim 15

A stirrer as defined in claim 8, wherein the improvement further comprises: resilient means mounted between said tie rod and said stirring element thereby resiliently limiting the transferable clamping force.

Claim 16

A stirrer as defined in claim 9, wherein said resilient means is a spring.

Claim 17

A stirrer as defined in claim 8, wherein said hub portion defines a bore and said stirring shaft includes an end seal having a frusto-conical sealing portion and a torque transmitting extension, and wherein said mounting means comprises: a holding mechanism which is adapted to mount said tie rod to said stirring element within the bore of said hub portion, said bore being configured to define a first portion having a surface which is generally parallel to the outer surface of said frusto-conical portion and defining a receiving space for said frusto-conical portion, a second portion defining a receiving space for said torque transmitting extension and a third portion defining an abutment surface for said holding mechanism.

Claim 18

A stirrer as defined in cLaim 11, wherein said holding mechanism comprises: a mounting plate having a central threaded bore within which said tie rod is threadedly received and a plurality of bolt receiving bores, said plate being adapted for reception within said second bore portion; and a plurality of adjustable abutment elements, each being rotatably mounted by a bolt to said plate at a respective one of said bolt receiving bores, and each being positioned relative to said plate so that said plate can be received into said second bore portion and thereafter each is positioned within said third bore portion and in engagement with said abutment surface.

Claim 19

A stirrer as defined in claim 8, wherein the improvement further comprises: resilient means mounted between said tie rod and said stirring shaft thereby resiliently limiting the transferable clamping force.

Claim 20

A stirrer as defined in claim 13, wherein said resilient means is a spring.

Claim 21

A stirrer as defined in claim 13, wherein said tie rod is provided with a head and said stirring shaft is provided with a shoulder, and wherein said resilient means is mounted between said head and said shoulder.

Claim 22

In a stirrer for stirring corrosive charges in corrosion resistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a metallic stirring shaft and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover having two end portions with one end portion being sealingly secured to the stirring element and the other portion being sealingly secured to the stirring shaft; a tie rod for clampably mounting said stirring shaft to said stirring element; and resilient means mounted between said tie rod and said stirring shaft thereby resiliently limiting the transferable clamping force.

Claim 23

In a stirrer for stirring corrosive charges in corrosion resistant, high pressure reaction tanks, such as glass-lined tanks, the stirrer including a metallic stirring shaft and a plastic stirring element attached to one end of the stirring shaft, the stirring element being fabricated as a one-piece element having a plurality of arms, the improvement comprising: a plastic cover covering a portion of the stirring shaft which contacts the corrosive charge, said cover having two end portions with one end portion being sealingly secured to the stirring element and the other portion being sealingly secured to the stirring shaft; a tie rod for clampably mounting said stirring shaft to said stirring element; and resilient means mounted between said tie rod and said stirring shaft thereby resiliently limiting the transferable clamping force.

Claim 24

A stirrer as defined in claim 16, wherein said resilient means is a spring.

Claim 25

A stirrer as defined in claim 16, wherein said cover has an intermediate portion between its secured end portions which is movable relative to said end portions.

Claim 26

A stirrer as defined in claim 18, wherein said cover is fabricated so that at least part of its length between its secured ends is resilient and thereby capable of returning to its initial shape when it changes its shape as a result of temperature changes.

Claim 27

A stirrer as defined in claim 16, wherein both said stirring element and said cover consist of polytetrafluoroethylene.