Innovative Bin Level Indicator
Locate Almost Anywhere
There are few limits on the mounting location. The shear resistant feature means that it may be
located high or low on the bin wall. Other technologies require a shield to prevent damage by the
weight of the material moving down in the bin. A shield is difficult to install and may interfere with the
operation. The Model SPM may be mounted almost anywhere except the top of the bin and requires
Resistant to Damage from Shear Forces
Many sensor technologies are easily damaged in low level applications by the force of the material as
it moves down in the bin. The weight of the material may bend a vibration, RF, or capacitance
probe. The moving material may damage the shaft or paddle on a rotary unit. The Hensortech
Swinging Paddle material sensor has a flexible section that allows the paddle to retract against the
bin wall if forced down by the weight of the material. When material moves away from the paddle, it
springs back, undamaged to its normal position. No shield inside the vessel is required.
Swinging Paddle Material Sensor
Locate in the Material Stream
Unlike other sensor technologies, the Hensortech Swinging Paddle Indicator may be mounted in the
material stream in most cases. It may even be mounted in the cone of a cyclone with no protective
shield. The paddle is somewhat inline with the material movement. The moving material tends to
slide off of the paddle and therefore not give a false indication. This is a great advantage when
mounting in a chute. The flexible section of the paddle prevents any large chunks which hit the
paddle from causing damage to the paddle or shaft.
Not Affected by Stringy Material
Stringy material may wrap up on the paddle of a rotary unit and may hang on the probe of an RF or
vibration unit, giving a false signal. Such material will slide off of the paddle of the Hensortech
Swinging Paddle Indicator.
The shaft and outer bearing is stainless steel. There are no ball bearings or lip seal. The stainless
shaft rotates in a stainless bearing surface. This construction is very resistant to damage due to
contamination or moisture and is easily cleaned. There is a purge opening between the outer
bearing and the enclosure, preventing any bulk material from leaking into the motor enclosure. A
very small amount of leakage will occur at the outer bearing. For most materials such as sawdust or
grain, this leakage is not significant. However, the Model SPM should not be used where zero
leakage is required.
Local Indication of Operating Status
A sunlight visible light indicates the presence of material at the paddle. The motion of the paddle
shaft can be easily viewed to confirm that the unit is operating properly.
The Swinging Paddle Indicator is inherently sensitive. The standard paddle has a swing radius of 7
inches. This is the equivalent of a 14 inch diameter paddle on a rotary unit. This large radius is
practical because the paddle only travels through a 60 degree arc. There is a very effective and
easily changed sensitivity adjustment inside the unit, also.
The exclusive system means speedy installation and even faster mounting. No large
holes or welded half-couplings are required. Simply lay out the holes with the included template.
Drill one 1 1/2” hole with a hole saw and 4 small holes for the mounting bolts. No welding or flame
cutting is required. A hole saw, drill bit, and cordless drill are all that is needed to install the
optional plate to the vessel wall. Then insert the unit and tighten one clamp screw.
This simple and reliable attachment is very convenient. By loosening only one screw, the model SPM
can be quickly removed and replaced for cleaning or inspection. There is no spinning of the unit
which often damages the electrical wiring. If the mounting surface for the model SPM is subject to
severe vibration, use the QM46AV anti-vibration mount.
318 Stacey Ann Cove Dripping Springs, TX 78620
1 1/4" NPT Mounting
If an existing location has a conventional 1 1/4" NPT half coupling mount, the model SPM is drop in
compatible. The half coupling should be no deeper than 1 inch. There must be room to swing the
paddle 360 degrees when mounting. The system should be used in all new locations.
See "SPM Series Mounting Options" for additional information.