ASI Instruments, represented in Australia by Micromax , has released the ShieldPoint series of radio frequency (RF) capacitance switches. The probe is built for point level detection in applications from sticky slurries to low dielectric bulk solids.
It has no moving parts to wear out and has LED operation and calibration lights, visible through its standard window cover, with an out of calibration indication. Its modular electronics are built around ASI's Ashield technology which provides immunity to material build-up, ensuring reliable and repeatable operation.
The ShieldPoint 300 is a single-point level switch with three-element shielded probes and a 10A DPDT relay. The ShieldPoint 400 is a multi-point switch with a variety of probe options, including a three-element probe, Teflon-coated or bare rods and cables, along with two SPDT 10A relays. The ShieldPoint 400 allows a choice of three operating modes - single setpoint, dual setpoint and pump control. The dual setpoint function means the unit can be used to replace two single-point switches for the cost of one.
ShieldPoint has a simple, one-step calibration process that uses an external magnet. With the LED indicator lamps, visible through the glass window cover, adjustments such as calibration, sensitivity and time delay can be made while maintaining the explosion-proof integrity of the switch. The out of calibration warning lets the user know when buildup is present on the probe and recalibration may be needed.
The ShieldPoint300 and ShieldPoint400 are housed in single compartment, powder-coated aluminum enclosures. Stainless steel enclosures are also available for corrosive applications where aluminum may not stand up to the elements. For hard to access installations, a remote mounting option with a range up to 200 feet provides user friendly flexibility. For increased protection, dual-compartment housings allow users to isolate wiring and terminations from internal electronics.
The ShieldPoint family includes a range of versatile probe elements, including a number of specialised options. Standard probes are available for multi-purpose applications. Stub or bent probes are available for small hoppers and vessels. Flexible or rigid tip extensions are available for increased range and cable probes are available for ranges up to 45m.
Custom pipe extensions are available for deep tanks or vessels for low-level switching, up to 6.1m. Rolled seals lock all elements of the probe in position and ensure no part of the probe can fall into the process or be blown from the mounting.