Manufacturer of Level Switch, Level Transmitter,
Detector and Sensor DITECH,LTD.
DITECH,LTD.
Guard type Level transmitter
QBS-G
NSB-G
proof
construction
Non-explosion-proof
Intrinsically safe construction(i3nG5)
This models are designed not to be affected by the adhering substance.
Measured powders adhere to the probe surfaces due to static electricity and/or the powder’s adhesiveness. The adhering powder comes off when its weight exceeds its adhesive force.
The adhesion and separation cycle is repeated. The density and relative permittivity of
the adhering substance are usually higher than those of the object to be measured.
Canceling out the relative permittivity of the air (which is 1), the ratio of the increased electrostatic capacitance of the adhering substance to that of the object to be measured is 1:3. This means that the adhering substance is highly liable to cause malfunctions since it exerts a triple influence.
The guard type level transmitter was developed by combining DITECH’s proprietary techniques, Capacitance & guard measurement systems, which means it will not be affected by the adhering substance.
principles
Capacitance measurement systems (a system of detecting capacitance that changes with increases or decreases of the object being measured) and Guard measurement systems (a system of preventing the erroneous signal transmission from the adhering to and accumulating on the surface of electrode by means of a third protection (guard) provided between the main detecting electrode and the grounding electrode.
Signals output by common probes are proportional to the thickness of the adhering substance and its relative permittivity. In contrast, the guard type probe keeps itself from outputting a signal until the thickness of the adhering substance reaches a preset value. This feature does not affect relative permittivity. The permissible thickness of the adhering substance can be varied according to probe dimension.
Even if the distance between the detector unit and transducer is extended, an extremely high stability of detection is practically obtainable by the adoption of high-grade circuit configuration and a special cable. In addition, the detector unit is composed of only metal and insulating material without using any electrical parts, so that the Model QBS-G, NSB-G level transmitter is usable in an extremely wide range of temperature and pressure. This level transmitter can also be used under radiation.
| Measurement range | Min. range 0～5mm , Max. range 0～150m (Any other range are possible) |
| Output signal | DC4～20mA DC1～5V ※ One of the above signal |
| Input power | Model QBS-G (Model PS-0G)： AC105V/210V 50/60Hz or DC24V Model NSB-G (Model PS-2)： AC105V/210V 50/60Hz |
| Power consumption | 10W |
| Linearity | ±0.5% FS |
| Allowable electrode conductance(G) |
3μS |
| Allowable electrode distribution capacity(Co) |
0～180pF or 0～500pF |
| Allowable temperature | Detector： －200℃～＋1100℃ (Depends on the specifications) Transducer： Model PS-0G： －10℃～＋50℃ Transducer： Model TR-2G： －25℃～＋70℃ Power source： Model PS-2： －10℃～＋50℃ Special cable： Model DSC-15 (high accuracy use)： －10℃～＋60℃ Special cable： Model DSC-05 (small size)： －10℃～＋60℃ Special cable： Model DSC-13 (heat resistance use)： －50℃～＋200℃ |
| Allowable load | Detector： 2000㎏ Concentrated at detection tip (Depends on the specifications) |
| Allowable pressure | Detector： 100MPa (approx. 1020kg/cm2G) (Depends on the specifications) |
| Weight | Transducer： Model PS-0G： 5.5kg Transducer： Model TR-2G： 4.3kg Power source： Model PS-2： 7.6kg |
| Size | Transducer： Model PS-0G： 216(W)×125(D)×259(H) Transducer： Model TR-2G： 200(W)×149(D)×220(H) Power source： Model PS-2： 250(W)×145(D)×275(H) (mm) |
| Installation | Detector： Flange mounting Screws mounting IDF Grayloc connector Ferrule Ring joint Lens Aminco Non-standard flange, etc. |
| Material | Detector： SUS304 SUS316 SUS316L Hastelloy Titanium Tantalum Nickel PTFE Ceramic, etc. Lining： PTFE Glass Rubber, etc. Head case： Light alloy SUS304 Salt resistant paint case, etc. |
Model QBS-G
(Non-explosion-proof type)
＜Separated transducer type＞
This model is composed of detector unit, transducer and special cable.
Model NSB-G
(Intrinsically safe construction / i3nG5)
＜Totally separated detector unit type＞
This model is composed of detector unit, transducer, relay power source and special cable that is 4 core control cable. As the transducer is designed to be installed in a dangerous area, the special cable can be made short enough to minimize picked-up noises, thus permitting a stable performance to be obtainable. As to performance, this model has the same characteristics as those of Model QBS-G.
