VWCM-4000 crack meters are used to measure movement across surface cracks and joints in concrete, rock, soil and structures.
They are accurate, highly reliable and suitable for use in harsh environments often found within civil engineering applications including water wells, boreholes, dams, reservoirs, rivers, tanks or any other body of water.
The sensor consists of an outer body tube and an inner free-sliding rod which is connected internally by a spring to a vibrating wire sensor. Anchors are attached at the sensor end of the outer body and the external end of the rod. The anchors can be fixed to each side of a crack to be monitored.
A change in distance between the anchors caused by the crack opening or closing causes the inner free-sliding rod to move within the outer body. This changes the tension on the spring and the vibrating wire thus altering the resonant frequency of the wire.
VWCM-4000 crack meters are installed by grouting, bolting, bonding or fixing expandable anchors to the structure to be monitored. The anchors incorporate ball joints where they are fixed to the gauge to accommodate any differential cross-axis movement and prevents the inner rod from binding within the outer casing.
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Ranges: 5, 12.5, 25, 20, 100, 150, 200, 300, 500 mm
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Resolution: <0.025% FS
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Accuracy: ±0.1 to ±0.5% FS
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Non-linearity: <0.5% FS
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Frequency range: 1650-2700 Hz
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Nominal zero value: 1850 Hz
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Body material: Stainless steel
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Inner rod: Stainless steel
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O-ring: Viton
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Anchor material: Mild steel, BZP
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Anchor types: Grout, bond, bolt, expandable
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Waterproof rating: 18 bar
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Cable: 2 pair PUR sheath
