Specification sheet
Model NDC
Absolute pressure
transmitter
Deltapi N Series
Pneumatic Transmitters
GENERAL CHARACTERISTICS
The blind type absolute pressure transmitter, mod. NDC, is
used to measure an absolute pressure and convert it into a
proportional pneumatic signal.
The instrument works on the force-balance principle and
consists of two main units:
the measuring unit comprises a main body which houses a
bellows unit, clamped in the main body forging by means of a
flange. The bellows unit incorporates an evacuated reference
chamber and releves the absolute pressure applied to the
positive connection port. The bellows unit can withstand the
maximum overrange without damage.
the transmission unit converts the differential force applied to
the measuring element into a proportional output pneumatic
signal.
The output pressure, generated by a flapper nozzle relay, is fed
to a feedback bellows with a rising pressure until the bellows
force balances that of the measuring element.
Span value continuously adjustable by an internal micrometric
screw.
Zero value adjustable by an external screw.
Mounting in a vertical position on 2in diameter pipe by a
special bracket.
OPTIONAL EXTRA FEATURES
A zero suppression device allows to set as a zero of the
transmitter a measured variable value different from the
absolute zero.
The sum of the zero suppression value (S) plus the calibrated
span cannot exceed the upper range limit (M) suitable by the
bellows capsule : S + span ≤ M (see table).
Air filter regulator can be directly mounted on the transmitter,
with or without pressure gauge, and connected with piping and
fittings either in stainless steel or copper.
Special versions of air filter regulator and gauges, in stainless
steel, are available on request.
Oxygen measurements a special degreasing and final test
operations can be required on the oxygen measuring
transmitter.
Air supply
nom. 140 kPa (1.4 bar, 20 psi); min. 125 kPa (1.25 bar,
18 psi); max. 175 kPa (1.75 bar, 25 psi)
Output signal
20 to 100 kPa/0.2 to 1 bar, 3 to 15 psi or 0.2 to 1 kg/cm2
Static air consumption
350 Nl/h
Maximum output flow
- with rising output pressure: 30 Nl/min.
- with falling output pressure: 40 Nl/min.
Accuracy
± 0.5% F.S.D. (typical)
Thermal drift (for ambient temperature variation between
-20° C and + 65° C)
- span 170 to 340 kPa (1.7 to 3.4 bar): 0.5%/10°C
- span 340 to 1700 kPa (3.4 to 17 bar): 0.25%/10°C
Degree of protection in accordance with IEC 529
IP55
Ambient temperature limits
-40 and + 120°C
Body and material
Carbon steel, AISI 316L, Monel
Body bolts and nuts material
high tensile carbon steel;
AISI 316 Class A4-70 per ISO 3506;
high tensile stainless steel, in compliance with
NACE MR0175
SPAN
LIMITS
170 and 1700 kPa
1.7 and 17 bar
RANGE LIMITS
(absolute)
lower and upper (M)
0 and 2500 kPa
0 and 25 bar
OVERRANGE
LIMIT
3.5 MPa
35 bar
MAXIMUM
ZERO
SUPPRESSION (S)
2330 kPa
23.3 bar
SPECIFICATIONS
The data were obtained from laboratory tests on standard instruments with:
carbon steel or AISI 316L body and flange; AISI 316L bellows unit; gasket: Viton;
calibration span: 800 kPa - 8 bar
Measuring bellows material
AISI 316L, Monel
Gaskets material
PTFE, Viton
Cover material
thermoplastic resin
Surface protections
- carbon steel body and flange: zinc plating and chrome
passivation
- AISI 316L body and flange: no protection
Process connections (see figure ref. D )
1/2 in NPT-F
Pneumatic connections
- Air supply (in figure ref. A): 1/4 in NPT-F
- Output (in figure ref. B): 1/4 in NPT-F
Pressure gauge
Brass with stainless steel case (all stainless steel on request)
external diameter 51 mm; 0-200 kPa, 0-2 bar and 0-30 psi
indication on 82 mm/260° scale.
Air filter regulator
with copper or stainless steel piping, as specified.
Die cast aluminium alloy with light grey epoxy finish.
Net weight (maximum)
14 kg approx
Packing
expanded polythene box
fg BODY AND FLANGE (*)
(*) Only the body is in contact with fluid
01
21
41
hi Bellows material
MEASURING ELEMENT
de VERSION
01
11
21
01
11
13
21
Standard with body bolts and nuts in high tensile carbon steel
Standard with body bolts and nuts in AISI 316
Standard with body bolts and nuts in high tensile stainless steel
Range limits - 0 and
kPa - psi Span limits
kPa (psi) - (Note 1)
Carbon steel / Carbon steel
AISI 316L / AISI 316L
AISI 316L / Carbon steel
Monel / AISI 316L
AISI 316L
Monel
AISI 316L (*)
170 and 1700 (24.6 and 246)
170 and 1700 (24.6 and 246)
170 and 1700 (24.6 and 246)
362
362
362
2500
2500
2500
ORDERING INFORMATION
Select one character or set of characters from each category and specify complete catalog number.
NDC
abc de fg hi j k lm
BASE MODEL
VERSION
BODY AND FLANGE
MEASURING ELEMENT
GASKETS
OUTPUT
EXTRAS
PRODUCT CODE
abc BASE MODEL
Absolute pressure transmitter
Code
Note 1: Multiply by 10 the value in kPa (MPa) to obtain mbar (bar).
(*) Suitable for oxygen service
2
3
GASKETS
(*) Suitable for oxygen service
Fulcrum diaphragm gasket
Viton
PTFE (*)
j
Viton
PTFE (*)
Measuring element gasket
k3 to 15 psi
3 to 15 psi with zero suppression device
0.2 to 1.0 kg/cm2
0.2 to 1.0 kg/cm2 with zero suppression device
20 to 100 kPa / 0.2 to 1 bar
20 to 100 kPa / 0.2 to 1 bar with zero suppression device
OUTPUT
According to
ANSI/ISA S 51.1-1979
standard terminology
1
3
4
6
7
9
Piping
material Air filter
regulator Pressure
gauge
EXTRAS
- -
- -
- -
with
with
- -
with
with
with
with
Identification
tag material
lm Stainless Steel
Stainless Steel
Stainless Steel
Stainless Steel
Stainless Steel
- -
Stainless Steel
Copper
Stainless Steel
Copper
02
10
11
13
14
Compliance to NACE class II bolting, according to specification MR0175, latest revision
The Company's policy is one of continuous product
improvement and the right is reserved to modify the
specifications contained herein without notice.
SS/NDC Rev 7
MOUNTING DIMENSIONS
D
ABB Inc.
125 East County Line Road
Warminster, Pa 18974
USA
Tel. (215) 674-6000
Facsimile (215) 674-7183
ABB Ltd.
Howard Road
St. Neots, Cambs.
England PE19 8EU
Tel. (01480) 475321
Facsimile (01480) 217948
ABB Instrumentation spa
Via Statale, 113
22016 Lenno (CO)
Italia
Tel. 0344 58111
Facsimile 0344 56278
