Pizzi - Long-stroke Vibrating Wire Extensometers

The long stroke vibrating wire extensometers, developed by Pizzi-Instruments, are produced with measuring ranges from 5mm up to 100mm, greater ranges are available upon request. Models with IP67 protection and IP68 protection with pressure resistance up to 100 meters of water column or higher are available.

Long-stroke strain gauges can be applied to mechanical, biaxial or triaxial devices and supports, to control deformations in two or three orthogonal directions (2D or 3D control). These vibrating wire instruments are compatible and usable with most of the vibrating wire data loggers available on the market.

However, we suggest, for manual readings, our portable datalogger DEC 3000 and DEC5 and, for automatic readings and systems, our datalogger CUM3000, VW-Brick 2, VW-Brick 8.

Our joint meters can be integrated into automatic monitoring systems and manage phenomena and alarms locally and remotely in real time.

For specific needs and requests, we are able to develop and manufacture customized products different from standard.

• Cracks in structures or rock
• Structural Joints
• Dams
• Galleries
• Rock Clusters
• Reinforced concrete or masonry constructions
• Monuments and buildings
• Landslides
• various
• Immersion applications at great depths

• High sturdiness
• Ease of installation
• Excellent resolution and sensitivity
• Excellent accuracy and linearity
• Accessories for 3D movement monitoring
• Completely build in stainless steel
• Integrated with temperature sensor (on request)
• Ideal for long-term monitoring
• High reliability over time

The body of the instrument is made of  two stainless steel tubes of different diameters and such as to slide one inside the other.

A harmonic steel wire is placed inside the two cylinders, whose final parts are connected, through an amplification system, to the two tubes. The sliding of the two tubes between them causes an elongation or shortening of the wire which will result in a variation of the vibration frequency of the same. Since the final parts of the instrument are fixed at the two points whose distance variations are to be measured, the elongation of the wire will be proportional to the variation in the distance between the two points.

They have an IP67 protection degree, guaranteed by two ORings placed for protecting the sliding area of the two tubes; the IP68 version is equipped with three O-rings with a special profile, that is, like those used for sealing in pistons, or could be equipped with external bellows

Technology:

• Vibrating wire
• Sensor of temperature:
• integrated

Range:

• Choice of values: 5mm, 10mm, 15mm, 20mm, 100mm; Higher ranges on request
• Accuracy: ± 0.2% f.s.
• Linearity: ˂±0.2%f.S.
• Sensitivity: ˂0.02%f.S
• Frequency Range: 500Hz÷1000Hz

Material:  

• Stainless steel

Wire:  

• Harmonic Steel

Anchorage type:  

• Dowels, threaded bars, frames
• Protection: IP67 o IP68 fino a 10 atm

Signal Cable:  

• 2×0.5mm2; 3×0.5mm2 integrated thermistor 2x1mm2; 3x1mm2
• Maximum distance from  Datalogger
• 1000 mt
• Accessories and Related Products
• 3D Jointmeter: Allows the mounting of 3 extensometers for control in the directions : X, Y,Z
• Fixing Kit for Y axis: Allows the assembly of the crack meter for the control of the Y axis
• Fixing kit for Z axis: Allows the assembly of the crack meter for the control of the Z axis
• Junction Panel: Available in different models for the connection of different instruments
• Multipolar Cable: Available with “n” conductors for connecting several sensors with a single cable
• DEC 5: Portable readout unit
• DEC 3000: Portable Datalogger
• CUM 3000: Mutichannel Datalogger
• MUX: Multiplexer for connecting different sensors to the Datalogger