Wet press with vibration control

Claim 2

A wet press of a paper-making machine for treating a paper web comprising: (a) a pair of first rolls defining a roll gap through which the paper web is conducted; (b) second rolls defining a closed loop path which includes said roll gap; (c) a belt-shaped felt guided by and revolving around said second rolls in the closed loop path, with the paper web and said felt being simultaneously conducted through the roll gap; (d) said second rolls including a tightening roll pivotally supported at one end, said felt being looped around said tightening roll with a section of the felt running toward the tightening roll and a section of the felt running away from the tightening roll; (e) a controllable positioning device connected to the other end of the tightening roll, said controllable positioning device being operable to tilt the tightening roll about said one end by a given tilt angle which lies in a plane located in the space between said felt sections and which passes through the longitudinal axis of the tightening roll; and (f) means for automatically varying the tilt angle including a controller operably coupled to said controllable positioning device, said controller operating said controllable positioning device at predetermined time intervals.

Claim 3

A wet press according to claim 1 wherein said controllable positioning device comprises a motor.

Claim 4

A wet press according to claim 1 wherein said controller further comprises a movable contact operably connected to said tightening roll, a pair of spaced stationary contacts cooperating with said movable contact to define angular limits for said tilt angle whereby the tilt angle is varied in equal angular steps in a first direction until one of said angular limits is reached and the next angular change of the tilt angle occurs in a second direction opposite to said first direction.

Claim 5

A wet press of a paper-making machine for treating a paper web comprising: (a) a pair of first rolls defining a roll gap through which the paper web is conducted; (b) second rolls defining a closed loop path which includes said roll gap; (c) a belt-shaped felt guided by and revolving around said second rolls in the closed loop path, with the paper web and said felt being simultaneously conducted through the roll gap; (d) said second rolls including a tightening roll pivotally supported at one end, said felt being looped around said tightening roll with a section of the felt running toward the tightening roll and a section of the felt running away from the tightening roll; (e) a controllable positioning device connected to the other end of the tightening roll, said controllable positioning device being operable to tilt the tightening roll about said one end by a given tilt angle which lies in a plane located in the space between said felt sections and which passes through the longitudinal axis of the tightening roll; and (f) means for automatically varying the tilt angle including a controller operably coupled to said controllable positioning device and a vibration sensor operably connected to at least one of said first rolls, said vibration sensor generating a signal indicative of the actual vibration of said at least one first roll, said controller operating said controllable positioning device as a function of the signal of the vibration sensor.

Claim 6

A wet press of a paper-making machine for treating a paper web comprising: (a) a pair of first rolls defining a roll gap through which the paper web is conducted; (b) second rolls defining a closed loop path which includes said roll gap; (c) a belt-shaped felt guided by and revolving around said second rolls in the closed loop path, with the paper web and said felt being simultaneously conducted through the roll gap; (d) said second rolls including a tightening roll pivotally supported at one end, said felt being looped around said tightening roll with a section of the felt running toward the tightening roll and a section of the felt running away from the tightening roll; (e) a controllable positioning device connected to the other end of the tightening roll, said controllable positioning device being operable to tilt the tightening roll about said one end by a given tilt angle which lies in a plane located in the space between said felt sections and which passes through the longitudinal axis of the tightening roll; and (f) means for automatically varying the tilt angle including a controller operably coupled to said controllable positioning device and a vibration sensor operably connected to at least one of said first rolls, said vibration sensor generating a signal indicative of the actual vibration of said at least one first roll, said controller operating said controllable positioning device as a function of the signal of the vibration sensor.

Claim 7

A wet press according to claim 4 wherein said vibration sensor comprises an acceleration sensor.

Claim 8

A wet press according to claim 5, wherein said controller includes means for calculating a mean value of the acceleration of said at least one first roll, said controller further including means for comparing the mean value of the acceleration to a reference value indicative of a vibration intensity limit, said controller providing a signal to operate said controllable positioning device as a function of the difference between said mean value and said reference value.

Claim 9

A wet press according to claim 5 wherein said at least one first roll comprises a hydraulically supported hollow roll including a stationary crosspiece extending through the hollow roll, said crosspiece having ends protruding from the roll with said sensor being mounted on one of said ends.

Claim 10

A wet press according to claim 7 wherein said controller includes means for calculating a mean value of the acceleration of said at least one first roll, said controller further including means for comparing the mean value of the acceleration to a reference value indicative of a vibration intensity limit, said controller providing a signal to operate said controllable positioning device as a function of the difference between said mean value and said reference value.

Claim 11

A wet press according to claim 4 wherein said controllable positioning device comprises a motor.