Tailored Safety Solutions

As the name suggests these applications requires a load to be lifted. At least one holding brake should be fitted to prevent falling due to mechanical or power failure. Depending upon the level of safety required these brake(s) can be diagnostically monitored every time they are engaged/ disengaged. Also wear monitoring is possible with some brakes as is automatic torque proving. Another possible safety feature would be a control mechanism to prevent over speeding.

Very often the transfer of goods will involve some human interaction at the end of the process. Safety measures may include operating a safe torque off function on the motor if an operator steps into a dangerous area. Another possibility is to safely limit the speed when an operator is in an ‘amber’ area so that the danger is easily avoided. Some systems can replace anti collision buffers with a control system that can guarantee safe position. This not only avoids the cost of mechanical buffers but will also provide extra space for storage which will provide continuous payback.

Depending upon the nature of the material being wound it may be desirable to safely stop the motors whilst maintaining a holding tension on the material. This can be done by controlling the drives to Safe Stop Category 2 EN 60204-1). In this standard the motor is shut down under control and then standstill is maintained. All control functions between the drive controller and the motor are maintained. After the safe operating stop is cancelled, e.g. by closing a guard door, the working movement of the motor can be continued immediately at the point of its interruption.

These systems very often require the lifting of the performers. The ratio of exposure to danger against total usage of the system is usually high. Most of these applications require the highest level of safety (PLe). For these type of applications our BBH range of safety PLC’s are amongst the market leaders.

Conveyor belt safety is important especially when heavy loads are being transported. An audible alarm should sound prior to movement to warn operators. Guards should be positioned at any potential nip points and sufficient and easy access to the emergency stop button or cable should be provided for. If the conveyor is not horizontal other braking measures may need to be taken.

In some instances the operator may need to access the piece that is being worked on. In these circumstances a combination of safe tip mode and safely limited increment may be required. So, for example, if a guard switch is opened the operator must press an enable switch and the work piece moves a safe incremented distance. To move it forward the operator must let go and press the enable switch again. Thus any crushing hazard is limited to the deemed safe distance parameterised.

Vacuum lifting equipment is widely used in many industrial sectors for the lifting and handling of materials/components that have a flat or smooth surface. There must be adequate maintenance procedures in place which monitor all seals that are vital to lifting.

The whole lifting system is dependent upon the vacuum pump for its safe operation. In the event of pump failure, the vacuum system must incorporate a one way valve located in the top of the lifting tube that automatically closes thereby maintaining the vacuum in the lifting tube. Should the vacuum reduce to an equivalent force that is less than the force exerted by the load, then the load will be automatically lowered.

Both gas and electric ovens are subject to strenuous safety legislation. There needs to be adequate safety measures against explosions (mainly gas related), fires and the prevention of personnel being trapped in the oven. The oven should have emergency shut down capability for which the electrical control system needs to interact in a safe way.