Safety when lifting, operating and servicing felt rolls

Press section felt rolls are designed to:

1. carry the felt with the desired tension
2. guide the felt and the web to the nip
3. leave the nip at an optimal angle for dewatering.

Safety when lifting rolls

When lifting the rolls, obey the OEM and mill safety instructions applied to the lifting occasion in question, the transfer during lifting or the devices used in lifting. In connection with the roll change, follow OEM and mill instructions for the roll change.

In connection with roll lifting, the following items must be taken into account:

• If the roll is equipped with mounting supports, always fix and lock them for the period of lifting the roll.
• The roll weight and lifting points
• The roll must always be lifted from two of the presented or determined lifting points.
• Take into account potential unequal loads at the lifting points.
• Check that the lifting device is suitable and in order. The devices must conform to regulations.
• Lifting method - with two hooks or with a lifting beam. When lifted with the beam, the roll must be absolutely stable.
• Lifting straps and ropes must be selected in accordance with the loads allowed for the lifting method. Also take into account special requirements, e.g. the minimum width of the lifting strap, or the lifting strap or rope types determined for the lifting occasion for some other reason.
• Check the condition of the lifting ropes and straps.
• The straps or the ropes must not slip during lifting.
• The ropes or the straps must not chafe against sharp corners. When necessary, use protection pieces.
• When transferring the rolls during lifting, choose the safest route.
• During lifting, it is prohibited to go under the hanging load. In connection with the roll transfer, other people must be warned about the hanging load.

Safety when operating rolls

The general safety instructions of the entire machine apply to and should be obeyed in the environment where the rolls are. The guards made for the rotating machine parts must be in place and properly installed.

Other points relative to operational safety:

• When the machine is running, avoid contact with the rotating and moving parts and the nips formed by nip rolls or other rolls close to each other or wires and felts.
• Water, air and lube oil system connections must be carefully connected. Flow amounts and pressures must conform to given values.
• Remove oil that has dripped on the floor or onto other devices.
• Check the reason for unusually strong vibration or operation noise and have it remedied.
• Immediately replace a web threading rope which has come off the groove, since it can break off and cause fire when chafing against the roll neck.
• The roll must be operated in accordance with the given instructions. The loads resting on the roll must conform to the given values. The same applies to potential temperature, roll speed, pressure resting on the surface etc.

Safety when servicing rolls

Before starting to service and repair the roll in the machine, check that the necessary interlockings and safe guardings of the machine have been connected and the roll operation has been switched off from automatic control. Warning signs showing that service duties are being made must be placed in their correct locations.

• When lifting roll parts, obey the safety instructions given for the lifting occasion.
• Lifting instruments such as a lifting eye screw etc., must be selected in accordance to the lifting method and the loads allowed.
• Lifting instruments must be carefully and appropriately attached to the piece to be lifted.
• The point from where the piece is to be lifted must be chosen in such a way that the lifting is safe and the piece cannot fall down or roll over during lifting.
• Dismounted roll parts must be supported by a base or by the floor to ensure that they will not fall down or start rolling.
• When using protective shoes, follow the instructions given for their use.
• When cleaning the roll shell with HP showers, it must be done very carefully, ensuring that the shower comes from a correct direction. Avoid directing water into the bearings.
• The tools and instruments used in service and repair duties, such as keys, pressure tools etc., must be safe to use (no broken or worn-out tools). Use tools and instruments correctly.
• When using cleaning agents in connection with roll service, obey the instructions given for their use.
• When the roll is lifted, obey the instructions compiled for roll lifting and the entire machine.

For more information and assistance with safe handling of felt rolls, contact your Valmet representative.