SD-40 Sludge Density Meter
Type SD-40 detects the density of sludge discharged from sedimentation tank and concentrators, in sewage treatment plants and water works. It achieves the accurate observation of sludge density, and helps to control the discharge of sludge.
| Newly Designed Detector | Principles of Measurement | Installation Location | Equipment Configuration |
- Automatic correction according to sludge color
Because the SD-40 automatically corrects for any change in sludge color, it can be used to observe black digested sludge. 
- Excellent sludge removal feature
The end of the detector is shaped to prevent sludge from adhering to it. In addition, SD-40 is equipped with an automatic cleaning mechanism as standard. Thus, the meter is capable of performing stable measurement over a long period. 
- Easy Maintenance
The detector can be checked without stopping the flow of sludge. Bypass piping is not required.
Specifications
| Type | Detector:SD-40 Converter:CV-40 |
|
|---|---|---|
| Measuring method | Dual scattered-light (With automatic color correction function) | |
| Measuring range | 0 to 8.0% of T.S.(Standard) | |
| Measuring accuracy (Repeatability) | ±2%F.S. (Bright sludge) ±5%F.S. (Black sludge) |
|
| Power source | 90 to 110V AC, 50/60Hz, 15A | |
| Ambient temperature | Detector : -5 to 50°C Converter : -5 to 50°C |
|
| Minimum velocity requirement | 0.03m/s(bright sludge),0.3m/s(black sludge) | |
| Output | Sludge density | 4 to 20mA DC |
| Warning | Upper/lower limit contact output (2) Fault contact output (1) |
|
| Control | Electromagnetic valve control | |
Newly Designed Detector
Flow prevents sludge from adhering the upstream face of detector. Therefore, placing the detection section on the upstream face reduces the sludge accumulation by the self cleaning effect, together with the automatic cleaner.
Principles of Measurement
The detector section irradiates two types of near infrared rays (A and B) from the end of the emitting optical fibers, receives the scattered light reflected from the sludge in the receiving optical fiber and converts it to an electrical signal.
The scattered light intensity of the received light is determined by the density and color of the sludge for each wavelength of the light. SD-30 reduces the influence of the sludge color through automatic correction using the difference of the correlation characteristic.
Installation Location
Equipment Configuration
Connecting Diagram
Example of Detector Connection Pipe
Ocean and River Instruments Division Web site