Bellofram Type 1000 E/P Tranducer

• Petrochemical processing systems

The Type 1000 Transducer is an electropneumatic device that reduces a supply pressure to a regulated
output pressure directly proportional to an electrical input signal. The Type 1000 accepts a wide range of
supply pressures, ranging from a minimum of 3 psig (0.2 BAR) above the maximum output up to 100 psig
(6.9 BAR). An integral pneumatic volume booster is included in the design to provide high flow capacity
(up to 12 SCFM/339 slpm). Model selections include General Purpose, NEMA 4 Type Option, Extended Range,
High Relief, Intrinsically Safe and Explosion Proof.

PRINCIPLE OF OPERATION

The Type 1000 Transducer is a force balance device in which a coil is suspended in the field of a magnet
by a flexure. Current flowing through the coil generates axial movement of the coil and flexure. The flexure
moves against the end of a nozzle, and creates a back pressure in the nozzle by restricting air flow through
it.  This back pressure acts as a pilot pressure to an integral booster relay. Consequently, as the input signal
increases (or decreases, for reverse acting), output pressure increases proportionally. Zero and span are
calibrated by turning easily accessible adjusting screws on the front face of the unit.  The zero adjusting screw
causes the nozzle to move relative to the flexure. The span adjusting screw is a potentiometer that limits the
current through the coil. A thermistor circuit in series with the coil provides temperature compensation.

SPLIT RANGING

The 4-20 mA input, 3-15 psig output model can be recalibrated to provide 3-9 psig or 9-15 psig output, for
split ranging applications.

MOUNTING

The Type 1000 transducers can be pipe, panel, or bracket mounted in any position. Positions other than

vertical will require recalibration of the zero adjustment. For maximum output pressure stability, the Type

1000 should be mounted in a vibrationfree location or such that vibration is isolated to the X and Z axis
shown on the dimensional drawings.

FIELD REVERSIBLE

All Type 1000 transducers are calibrated at the factory for direct acting operation but may be used in the
reverse acting mode by reversing the polarity of the signal leads and recalibrating. When calibrated for
reverse acting applications, the Type 1000 transducers provide a minimum of their full rated output pressure
(i.e., 15, 27, or 30 psig) upon input signal failure.

The Type 1000 I/P and E/P Transducers are more cost effective and more accurate than typical high output
systems using transducers coupled to boosting or multiplying relays.