From IBS Power Products
Stock Equipment offers coal monitors for detecting material flow or presence in pipes and downspouts. They are particularly suited to installations where due to licensing or administrative restraints, nuclear type detectors are undesirable.
The acoustic flow monitor detects material flow. Care has been taken in designing the contact portions of the probe to ensure maximum life under highly abrasive material conditions.
The microwave level detector confirms the presence of material by having a transmitter and receiver across the material stream. It is not dependent on the motion of the material for indication. There are no components that protrude into the material stream.
The alarm signal from either type of monitor can be used to operate vibrators, air cannons, etc. A second monitor may be located immediately above the feeder, and used to trip the feeder if material flow has not been reestablished prior to loss of all material within the system. As an alternate, this secondary alarm indication can be provided with a Stock® microprocessor controlled gravimetric feeder through “countdown” circuit within the feeder controls.
The detector unit consists of a stainless steel probe which contacts the moving material and provides the physical link to the piezoelectric element housed in the detector assembly. Mechanical vibrations are converted by the piezoelectric element, resulting in a signal that is transmitted to the control unit. The detector is isolated with elastomers to prevent misalignment and ensure positive transmission of mechanical vibrations from the flow material.
The detector control unit consists of a dust- and water-tight enclosure housing the electronic circuitry. The control features status light indicators, signal strength monitor (visual), and provisions for calibration during operation without false alarms through a 'guarded' relay circuit.
The acoustic flow monitor should be mounted on the downspout as close to the bunker (or silo) outlet as is physically practical. By so doing, the ealiest possible indication of loss of flow is ensured.
Stock Acoustic Flow Monitors Provide a Positive Indication of Flow or Loss of Flow in Your Feed Systems
The acoustic flow monitor has been developed to provide a reliable method of detecting material flow or flow interruption in pipes and downspouts. It is particularly suited to installations where, due to licensing or administrative restraints, nuclear type detectors are impractical.
The acoustic flow monitor consists of two subassemblies: a detector probe that mounts on the downspout and a control unit suitable for wall mounting in a convenient location. The detector probe includes a stainless steel alloy tip that protrudes through the downspout wall into direct contact with the moving material.
The control unit includes the required electronics, comparator circuitry, and alarm relay to advise system status. Adjustment and calibration are easily accomplished at the control unit.
Should flow stop during normal operation, the alarm signal can be used to automate vibrators, air cannons, or other devices. A second acoustic flow monitor may be located immediately above the feed system and used to trip the feeder if material flow has not been reestablished prior to loss of all material within the system. As an alternate, this secondary alarm indication can be provided with a Stock® microprocessor controlled gravimetric feeder through “countdown” circuit within the feeder controls. Optional mounting fixtures and hardware are available upon request.
The acoustic flow monitor represents a highly reliable method of remotely monitoring material flow. Care has been taken in designing the contact portions of the probe to ensure maximum life under highly abrasive material conditions.
As material flows through the downspout, sonic waves are generated at the friction interface between the material and downspout wall, material and sensor probe, and by material particles moving against one another.This sound vibration is transmitted as a physical motion through the tip of the sensor probe.This motion is proportionally converted by a piezoelectric element to an electrical signal, which is forwarded to the control unit. Within the control unit, the signal is amplified and filtered to eliminate non-flow related interference.The incoming signal activates and maintains a 'material motion' status. In the event of an empty downspout or one full or partially loaded with non-moving material, the 'material motion' signal drops below a set point, providing a contact closure showing pluggage has occurred. An adjustable 10 to 90 second time delay is included in the circuit to prevent nuisance alarms caused by spike vibratory conditions
- Type: Contact - Acoustic Flow Detector
- Size: Detector - 9” long, Flange - 7-1/2” dia, Control Unit - 9-3/4”w x 12-1/2”h x 5-1/4”d, suitable for wall mounting, bottom cable entry, front door access
- Power Requirement: 120V ac, single phase, 50/60 Hz, 5 VA or 240 V ac, single phase, 50/60 Hz, 5 VA
- Outputs: One normally open (form A) dry relay contact rated at 120 V ac, 3A, 360 VA, resistive or 125 V dc, 0.24 A, 30 W, resistive. One normally closed (form B) dry relay contact rated at 125 V ac, 3A, 150 VA, resistive or 125 V dc, 0.24 A, 30 W, resistive. Adjustable time delay - 10 to 90 seconds. (Factory set @ 10 seconds)
- Ambient Requirements: -20°C to 65°C (-4°F to 150°F) - Detector, -20°C to 60°C (-4°F to 140°F) - Control Unit, (NEMA 4 - Standard)
- Type of Sensor: Contact - Piezoelectric Transducer