Static Control for Safe Operation of Process Machinery
Dust collection • powder grinding, pulverizing, mixing & blending • fluid bed drying • etc.
- Self testing system
- Insures correct grounding
- Monitors up to 8 points
- LED status indication
- Includes interlock control contact(s)
- Intrinsically safe
- ATEX certified
- Suitable for fixed and temporary clamped connections
Problem: static electricity in hazardous atmospheres is ever present in many sectors of the processing industries. Effective grounding and bonding procedures are always the first step in controlling static, with special techniques being called for to suit individual applications.
Typical risks exist with items of process plant incorporating sections which must be removed periodically for cleaning or other purposes. An example of this is the product bowl on a Fluid Bed Dryer, but there are many other similar applications such as ductwork sections, conveying systems etc.
Removable parts may become isolated conductors if they do not have a sufficiently low resistance path to ground to enable any static generated to safely dissipate. If this happens, high levels of charge may accumulate on the isolated part posing the risk of energetic static discharges (sparks). If this occurs in a hazardous atmosphere there will be a chance of a resulting fire, explosion or dangerous physiological shocks for operators.
Schematic diagram of a Newson Gale Earth-Rite Multipoint static control system used to protect a piece of process machinery
Solution: Earth-Rite MULTIPOINT ensures that all parts of the equipment are connected together and to ground by using a unique intrinsically safe monitoring system. An important design criterion of the Earth-Rite MULTIPOINT ensures that the sum of all circulating currents does not compromise the intrinsic safety of the monitoring system. This is achieved by supplying the monitoring system from a single I.S. supply, which may be used to monitor up to eight separate points.
The system provides permissive outputs only when the ground loop resistance of each utilised channel is less than 10 ohms, as recommended in the various International standards for the control of undesirable static electricity. The Earth-Rite MULTIPOINT may be used to provide status indication for the equipment, or automatically linked back to a control system to prevent operation until the required bonding and grounding conditions have been achieved. The system is ATEX approved for use in hazardous atmospheres and meets all current EC directives.
Earth-Rite MULTIPOINT Basic Specification
Approvals & Certification
|Monitoring Unit: (ATEX) II 1 GD EEx ia IIC T4
Power Supply / Interface: (ATEX) II 1 GD [EEx ia] IIC
|Power supply||110/120V or 220/240V AC 50-60Hz|
No. of Monitored Points
|Up to 8 (hard wired or via clamps)|
|Setpoint: 10 ohms (each point)|
|Red & green LEDs for each point|
|One common contact output|
|Multiple interlock output contacts,
Ground monitoring clamps and cables for mobile equipment,
Fixed monitoring leads with plug & socket connectors.