Manufacturer of Level Switch, Level Transmitter,
Detector and Sensor DITECH,LTD.
DITECH,LTD.
Spinning type
Flat type
Flat type
Breakwater pipe type
With purge port
In-pipeline type
Glass-lined electrode
Model NQH-1
Model NQH-2
Model NSH-1-1
Model NSH-2-1
Model NSH-1-2
Capacitive Level switch
NQH
NSH
proof
construction
Non-explosion-proof
Intrinsically safe construction(i3nG5)
Flameproof construction(d2G4)
Capacitive level switches are available with a series of models such as Straight-rod probe type, Flat probe type, Wire type, In-pipeline type and etc. which are mainly suitable for measuring the insulating material.
Level switches other than the Model NSH(NQH) operate as if the object to be measured approached, when the leakage resistance (the term "leakage resistance" to be referred to hereafter includes d-c resistance and dielectric resistance) lowers to 105Ω or lower.
When the leakage resistance drops to around 104 to 103Ω, they cause an error in operation by signalling the detection of the object to be measured even when they do not make any contact with the object measured at all (even when there is no increase in electrostatic capacity).
Moreover, even if their setting is changed to lower sensitivity or the model is changed to that for lower sensitivity, all that can be expected is slight parallel shifting.
It is a known fact that with most substances an decrease in their leakage resistance indicates an increase in their dielectric constant. Because of this fact, conventional level switches cannot provide stable operation against the objects to be measured whose state changes.
Since the Model NQH and NSH is provided with the characteristics that its electrostatic capacity detecting ability becomes lower when the leakage resistance decreases below 105Ω, it shifts to low sensitivity without requiring any alteration in setting at all, as the deposition or build-up of the objects to be measured increases, thus it always insures stable operation.
Every material has intrinsic electrical characteristics. When a liquid, powdery material, or the like comes in contact with or close to the electrode installed inside the tank, both the capacitance and conductance between the electrode and tank wall will vary if the dielectric constant and dielectric loss of the substance differ from those of air or other substances. The detection sensitivity of the switch is automatically adjusted by correcting them mutually.
The capacitive level switch has 5 kinds in types (Wide range type, Low sensitivity type, Standard type, High sensitivity type and Ultra-high sensitivity type) depending upon the object to be measured.
| Type Y | Ultra-high sensitivity type |
| Type X | High sensitivity type |
| Type A | Standard type |
| Type B | Low sensitivity type |
| Type C | Wide range type |
| Measurement type | Automatic correction capacitance type |
| Stable detection range | Min ≦ 0.1pF(Type Y) Max ≧ 15000pF(Type C) Peculiar resistor ∞～0.5Ω(Type Y ～ Type C) |
| Output contact | Model NQH： a,c,b 200V 1A 100VA (Non-inductive load) / Open collector / Thyristor / SSR Model NSH(Model PS-7)： a,c,b 200V 1A 100VA (Non-inductive load) Model NSH(Model PS-8)： a,c,b 250V 5A (Non-inductive load) |
| Input power | Model NQH： AC105V/210V 50/60Hz or DC24V Model NSH(Model PS-7)： AC105V/210V 50/60Hz Model NSH(Model PS-8)： AC105V/210V 50/60Hz |
| Power consumption | Model NQH： 4.5W Model NSH： 4W |
| Time lag | Model NQH： 0～10sec Variable (option) |
| Allowable temperature | Detector： －200℃～＋1100℃ (Depends on the specifications) Transducer： Model PS-3： －10℃～＋50℃ Transducer： Model TR-6： －25℃～＋70℃ Power source： Model PS-7： －10℃～＋50℃ Power source： Model PS-8： －10℃～＋50℃ Special cable： RG(standard type)： －10℃～＋60℃ Special cable： TEF(heat resistance use)： －200℃～＋260℃ |
| 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-3： 2.0kg Transducer： Model TR-6： 1.75kg Power source： Model PS-7： 2.0kg Power source： Model PS-8： 7.8kg |
| Size | Transducer： Model PS-3： 154(W)×95(D)×166(H) Transducer： Model TR-6： 154(W)×95(D)×166(H) Power source： Model PS-7： 80(W)×101(D)×210(H) Power source： Model PS-8： 220(W)×78(D)×262(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 NQH-1
(Non-explosion-proof type)
＜Integrated transducer unit type＞
This model is of compact type in which both detector unit and transducer are integrated.
Model NQH-2
(Non-explosion-proof type)
＜Separated transducer type＞
This model is composed of detector unit, transducer (relay power source) and special cable. Transducer may be installed far from the area exposed to Heat, Steam, Vibration, Powder or Gas. This is Non-explosion-proof type and has the same characteristics as those of Integrated transducer unit type as to performance.
Model NSH-1-1
(Instrinsically safe construction / i3nG5)
＜Integrated transducer unit type＞
This model is composed of detector unit with self-contained transducer and relay power source (Model PS-7). The transducer contained in the detector head requires no special cable. For this reason, the dangerous area may be kept away unlimitedly from the safe area. As to performance, this model has the same characteristics as those of Model NQH.
Model NSH-2-1
(Instrinsically safe construction / i3nG5)
＜Separated transducer type＞
This model is composed of detector unit, transducer, relay power source (Model PS-7) and special cable. The transducer may be installed far from the area exposed to Heat, Steam, Vibration, Powder or Gas. This model has the same characteristics as those of Model NQH and the equivalent performance to those of Integrated transducer unit type.
Model NSH-1-2
(Flameproof construction / d2G4)
＜Integrated transducer unit type＞
This model is composed of detector unit with self-contained transducer and relay power source (Model PS-8). The transducer contained in the detector head requires no special cable. For this reason, the dangerous area may be kept away unlimitedly from the safe area. As to performance, this model has the same characteristics as those of Model NQH.
Model NSH-2-2
(Flameproof construction / d2G4)
＜Separated transducer type＞
This model is composed of detector unit, transducer, relay power source (Model PS-8) and special cable. The transducer may be installed far from the area exposed to Heat, Steam, Vibration, Powder or Gas. This model has the same characteristics as those of Model NQH and the equivalent performance to those of Integrated transducer unit type.
