Johnson filters inspection machine

Johnson filters also called Wedge Wire Screen or Johnson Screen or Wedge Wire Profile are intended for the construction of high-quality water wells, oil wells, gas wells and other filtration equipment.

The inspection machine is designed for control of one of the main parameters characterizing the quality of the filter, namely, the constancy of the interwire gap (slot opening) along filter length.

Johnson filters inspection machine. Specification


Parameter Value
Measurement object Wire filter
Controlled filters length, up to, m 8 (can be changed on request)
Controlled gaps, mm 0.05...2
Wire width, mm 1...4
Gap measurement error, mm ±0.010 (when the curvature of the part is within ±4 mm)
Scan speed, up to, mm/s 100
Power supply Three-phase AC network with frequency (50 ± 1) Hz, rated
voltage 220/380 V with voltage tolerance ±10%
Power consumption, W 400
Operating mode Round-the-clock operation
Operating conditions Workshop (temperature 10…30°С, relative humidity at Т=25°С
no more than 80%
Readjustment for measuring another part Not required if readjustment is not associated with a shift in the
position of the filter axis outside the scan area
Computer Industrial computer, 19” touch screen
Computer console dimensions, mm 1509х800х550

Johnson filters inspection machine. Specification

Industrial camera

Parameter Value
Scan area size, pixels 1440x100
CE сompliance RoHS, FCC Class B, CE, IP30, GenICam, UL, KC, EAC
Operating ambient temperature, °С 0...+50

The machine is installed along the filter. The industrial camera is placed in such a way that its field of view is located in the diametrical section of the filter. The camera moves along the filter and captures the image of its surface. Before scanning the filter, the system is auto-calibrated by measuring the built-in template. The software analyzes the received image and calculates the dimensions of the gaps. The process is repeated for different positions of the filter as it gradually rotates around the axis.

Data from the camera is processed on the central computer. If the values of the parameters go beyond the specified limits, a corresponding warning is displayed on the screen of the central computer.


The machine contains a frame (1) installed along the filter. The frame carries the linear motion system (2). An industrial camera (4) with LED illumination is installed on the carriage (3) of the linear motion system. In the extreme position of the carriage (outside the controlled filter), the calibration template (5) is installed. The machine is powered and controlled via a central computer using specialized software.

Figure 1. Block diagram and general view of the system.

Figure 1. Block diagram and general view of the system

Overall and mounting dimensions
The overall dimensions of the machine are shown in Figure 1.
The overall dimensions of the central computer rack are shown in Figure 2.

Рисунок 2. Структурная схема и общий вид системы.

Figure 2. The overall dimensions of the central computer rack

Johnson filters inspection machine, demo-video.

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