HM1151 Capacitor -type Differential Pressure Transducer

? ? ? Working Principle? ? ?

The process pressure is transferred to the central measuring membrane of    δ chamber through the isolating membrane on both sides or one side. The    central membrane is a tensioned elastic element, which may generate    corresponding deformation displacement for the pressure difference on the    both side applied on it, of which displacement is direct proportion to the    pressure difference. The maximum displacement is approximately 0.1mm. This displacement is    converted into a differential capacitance formed on the capacitor pole board    and the differential capacitance is converted into 2 – wire 4 ~ 20mA signal    output through electronic circuit.

Range of measurement:

0 ~ 0.125KPa ~ 40MPa

Signal output:

4 ~ 20mA

Power supply of energization

12 ~ 45V DC (24V DC    generally)

Load characteristic:

Related to the power    supply of energization. The load impedance RL has a relationship to the    voltage of the  power supply: RL ≤50    (VS – 12) Ω 

Indicating gauge:

Pointer type with an    indication 0 ~ 100% scale, LCD display (0 ~ 100% linear) and square root    indication 0 ~ 10 scale.

Explosion – proof:

a. Explosion –    isolating type d II BT4

b. Intrinsically safe    type in II CT6

Measuring scale and zero point:

Externally and    continuously adjustable

Positive and negative immigration:

The lower and upper    limit of the scale shall not exceed the scale limit after positive and    negative immigration.

Maximum positive    immigration: 500% of the minimum measuring scale

Maximum negative    immigration: 600% of the minimum measuring scale

Range of temperature:

The range of operating    temperature for the amplifier: -29 ~ +93℃ (: -25 ~ +70℃ for LT type)

The measuring element    filled with silicon oil: : -40 ~ +104℃

Flange –type    transducer filled with high – temperature silicon oil: : +15 ~ +315℃; that filled with    general silicon oil: : -40 ~ +150℃

Static pressure and overloading pressure:

4, 10, 25, 32MPa

Humidity:

Relative humidity (RH)    0 ~ 100%

Volume intake capacity:

＜ 0.16cm3

Damping (step response):

Continuously    adjustable, between 0.2s ~ 1.67s generally when filled with silicon oil.

Starting time:

2s, preheating is    unnecessary.

Accuracy:

 ± 0.25% FS; ± 0.5% FS

Dead zone:

None (≤ 0.1%)

Stability:

Not exceeding the    absolute value of the basic tolerance for the maximum scale within six    months.

Influence of temperature:

Under the maximum    scale: zero position tolerance is ± 0.1% / 55℃, the total tolerance is ± 0.15% / 55℃.

Under the minimum    scale: zero position tolerance is ± 0.1% / 55℃, the total tolerance is ± 0.2% / 55℃.

Influence of vibration:

On the any axial    direction, the tolerance is  ± 0.05% / g    of the upper limit of the measuring range when the frequency of vibration is    200Hz.

Influence of power supply:

Less than 0.005% / V    of the scale output

Influence of load:

The load has no    influence to it if the power supply is stable.

Influence of installing position:

0.24KPa zero point    tolerance may be generated, as a maximum, but it may be corrective, without    influence to the measuring scale.

Isolating membrane:    316LSST, Hastelloy alloy C, MONEL, or tantalum.

Gas exhaust / liquid    discharging valve: 316LSST, Hastelloy alloy C, MONEL

Flange and joint:    Electroplated carbon steel, 316LSST, Hastelloy alloy C, or MONEL

O – ring contacting    medium: NBR, fluorubber

Oil filled: Silicon    oil or inertia oil

Enclosure of    electronic parts: Low – copper aluminum alloy

Pressure – leading connecting part:

The connecting screw    hole on the pressurized vessel or chamber is 1 / 4 ~ 18NPT, the connecting    screw hole on the pressure – leading joint is 1 / 2 ~ 14NPT.

Connecting hole of the signal wire:

G1 / 2

Weight:

Approximately 5.4kg (excluding    accessories)

Standard accessories:

The flanged joints, gas    exhaust valves and liquid discharging valves and one book of instruction    manual have been provided for all the variants in the factory before    delivery.