Cameron Barton 199 User manual

MODEL 199
DIFFERENTIAL PRESSURE UNIT (DPU)
Standard and NACE Service
User Manual
Manual No. 9A-10030, Rev. 01
January 2008
CONTENTS
Section 1 - Introduction.................................................................. Page 3
Section 2 - Theory of Operation.................................................... Page 5
Section 3 - Installation/Operation ................................................ Page 9
Section 4 - Maintenance, Adjustment, & Calibration................. Page 13
4-1. Tools Required for Maintenance and Calibration............. Page 13
4-2. DPU Inspection and Cleaning............................................. Page 13
4-3. Calibration Setup.................................................................. Page 18
4-4. Torque Tube Rotation Check (Replacement Units) ......... Page 18
4-5. Range Change....................................................................... Page 19
4-6. Setting Bellows Travel .......................................................... Page 22
4-7. Bellows Unit Assembly (BUA) Replacement.................... Page 22
4-8. Attaching Drive Arm to Torque Tube................................. Page 24
4-9. Drive Arm Tightness Test .................................................... Page 24
4-10. Adjusting Pulsation Dampener ......................................... Page 25
4-11. Troubleshooting .................................................................. Page 25
Section 5 - Parts Drawing/List ....................................................... Page 27
Section 6 - Outline Dimension Drawings ..................................... Page 30
(This manual is for the DPU only.) Refer to the appropriate (separate)
instrument manual for information on the instrument being actuated.

Barton instrument is as stated on the back (last

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SECTION 1 - INTRODUCTION
1-1. General
The Barton®Model 199 Differential Pressure Unit (DPU) (see Figure 1 -1) is a
mechanical device which accurately measures differential pressure relative to a
gas or liquid flowing through a process system, or to the level of a liquid con-
tained in a process vessel.
For process ow measurements, the DPU is connected across a primary device
(a venturi, an orice plate or a ow tube) located in the process system.
For liquid level measurements, the DPU may be connected in a variety of ways
to measure the difference in pressure caused by variations in the level of the
liquid in the process vessel.
1-2. Product Description
The Model 199 DPU is a dual
bellows assembly enclosed within HP Housing LP Housing
Connection
Pressure
pressure housings. The dual
bellows assembly consists of two
opposing internally connected liq- Venting
uid-lled bellows, a center plate, Connection
range springs, overrange valves, Torque Tube
and a torque tube assembly. Shaft
The pressure housings are con-
nected by Pipe or tubing to the
primary device located in the sys- Mounting
tem piping. Variations in differen- Bracket
tial pressure within the pressure
housings cause the bellows to expand or contract in a linear direction towards
the side having the lowest pressure.
The linear movement of the bellows is converted into angular rotation when
transmitted to the torque tube shaft by the drive arm and this mechanical mo-
tion actuates the mechanism of the process monitoring instrument.
The process monitoring instrument that is connected to the torque tube as-
sembly may be an indicator, a switch, a transmitter, a recorder, or other process
control device.
1-3. Specications
Torque Tube Rotation (full scale DP).............8° ±10%
Torque Tube Material..................................Beryllium Copper (BeCu)
Temperature Limits ....................................-40°F/°C to +180°F (+82°C)
Maximum Non-linearity:
0-10" w.c. to 0-400" w.c.
(0-25 mbar to 0-993 mbar) .........................±0.5% of full scale with
appropriate linkage
0-401" w.c. to 0-100 psi
(0-996 mbar to 0-6.9 bar) ...........................±0.75% of full scale with
appropriate linkage
Repeatability ..............................................0.20% of full scale DP
Housing Materials/Ranges ..........................Refer to Table 1-1
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Table 1-1. Model 199 DPU Material/Range Specications
SWP
psi
(bar)
Body Housing Material
Available DP Ranges
Stainless Steel Bellows Inconel Bellows
2-1/8" (55mm) O.D. 3-3/4" (95mm) O.D. 2-1/8" (55mm) O.D. 3-3/4" (95mm) O.D.
1,000
(69)
Cast Aluminum 356T6 Forged Stainless Steel 316
0-15 psi to 0-100 psi
(0-1 bar to 0-6.9 bar)
0-10" w.c. to 0-400" w.c.
(0-25 mbar to 0-993 mbar)
0-15 psi to 0-100 psi
(0-1 bar to 0-6.9 bar)
0-10" w.c. to 0-400" w.c.
(0-25 mbar to 0-993 mbar)
NACE
2,000
(138)
Forged Steel AISI C1018 (For NACE Service)
2,500
(172)Forged Steel AISI C1018
3,000
(207)Forged Stainless Steel 316
4,500
(310)Forged Alloy Steel 4142
6,000
(414)
Forged Alloy Steel 4142 Forged Stainless Steel 17-4 PH
Net Volume in cu. in. (cc)
Low Pressure (LP) Head 35" (575 cc) 30" (490 cc) 35" (575 cc) 30" (490 cc) High Pressure (HP) Head 31" (510 cc) 26" (425 cc) 31" (510 cc) 26" (425 cc)
Displacement in cu. in.(cc) for full-scale travel
0.5" (8.2 cc) 1.5" (25 cc) 0.5" (8.2 cc) 1.5" (25 cc)
NOTES: Zero center or split ranges available on special order (e.g., 0-50" w.c. (0-124 mbar) range may be ordered 25-0-25" w.c. (62-0-62 mbar) or 10-
0-40" w.c. (25-0-99 mbar). Intermediate DP ranges available from 0-20" w.c. to 0-100 psi (0-50 mbar ot 0-6.9 bar). Other sizes and types of connectui-
ons (welding stubs, MS, A.N.D., etc.) available upon request. Standard pressure connections are 1/2" (top) and 1/4" (bottom) NPT. Range springs are not interchangeable between the different size bellows, the inconel bellows, or the 10" w.c. (25 mbar) range. 3,000, 4,500, and 6,000 SWP versions can be specied to meet NACE MR-01-75 (Rev. 80). Metric conversions are approximate. Outline dimension drawings available upon request.
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SECTION 2 - THEORY OF OPERATION
2-1. Basic Components (See Figure 2-1)
LP Housing
HP Housing
Shaft Center Plate
Compensator
Housing
Bolts
Pulsation Damper
Torque Tube
Torque Tube LP Bellows
Range Spring
HP Bellows
HP Over-
range Valve
Temperature
Valve Stem
LP Overrange
Valve
Damping Valve Plug
Figure 2-1. 199 BUA Cutaway
A. Pressure Housings
The two pressure housings of the Model 199 DPU are available in the vari-
ous safe working pressure ratings dened in Table 1-1 and in the Outline
Dimensional Drawings (seen in Section 6 DRAWINGS).
Each pressure housing has two tapped connection ports: one port is located
in the top of the housing, the other port is located in the bottom of the
housing.
The pressure housings may be rotated 180 degrees to facilitate connection
at the top of the housing for draining when used in gas service, or at the
bottom to provide venting when used in liquid service.
The housings enclose the bellows on each side of the center plate.
B. Bellows
The bellows of the Model 199 DPU are available in the various materials
and sizes (refer to Table 1-1) to accommodate the various safe working
pressure ratings.
The DPU has two bellows. One end of each bellows is sealed. The open
end of each bellows is attached and sealed to a side of the center plate (one
bellows on each side).
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The bellows and center plate are lled with ll liquid via the drive arm hole
plug. An opening through the center plate provides a passageway for the
transfer of ll liquid between the two bellows. This opening also allows the
bellows to be connected internally by a valve stem.
C. Range Springs
The range of the dual-bellows type DPU is determined by the force required
to move the bellows through their normal range of travel.
The range springs, which are available in various ranges (refer to
Table 1-1), act with the bellows and torque tube to balance the differential
pressure applied to the unit. The number of springs used and their spring
rate depends on the individual differential pressure range requirement.
Drive Arm
Hole Plug
(DO NOT LOOSEN)
Retainer
Screws
Torque Tube Gland Nut
(DO NOT LOOSEN) Range
Spring
Assembly
Push
Rod
Torque
Tube Lock
Shaft
Range Nut
Springs
2-1/8" Bellows Unit Assembly (BUA)
Drive Arm
Hole Plug
Retainer Nut
End Cup
Push Rod
Nut
Range
Shaft
Spring Post
(DO NOT LOOSEN)
Range Spring
Assembly
Spring
Lock
Springs
Torque
Tube
Torque Tube Gland Nut
(DO NOT LOOSEN)
3-3/4" Bellows Unit Assembly (BUA)
Figure 2-2. Bellows Unit Assemblies (BUAs)
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D. Torque Tube Assembly
Needle Beaing
Center Plate
Disc
0.200"
Minature
Precision
Shaft
O-Ring Seal
8°
Rotation
Weld
Drive Arm
Valve Stem
Bellows Travel
Valve Stem
Ball Bearing
Torque Tube
Torque Tube
Torque Tube
Lock Nut
Weld
Ball Bearing
Figure 2-3. Torque Tube Assembly
As illustrated in Figure 2-3, the torque tube assembly consists of a torque
tube, a torque tube shaft, and the supporting members. The outboard end
of the torque tube shaft is attached to the center plate. The torque tube
shaft, located in the center of the torque tube, is welded to the inboard end
of the tube.
Movement of the bellows is transmitted by the drive arm to the torque tube
as a rotary motion. Since the torque tube is attached to the center plate,
the tube must twist when subjected to torque. The torque tube shaft, which
is freely supported within the torque tube at its outer end, but connected
to the torque tube and drive arm at its inner end, rotates through the same
angle as the differential pressure unit.
NOTE: An extended torque tube is used on electronic transmitters and
explosion-proof instruments.
E. Pulsation Dampener
The pulsation dampener (see Figure 2-1) controls the ow of ll-liquid
between the high and low-pressure bellows with an externally adjustable
pulsation dampener needle valve. Restriction of liquid ow reduces the
effects of pulsation. In applications where pulsation is not a problem, the
needle valve is set to the fullopen position.
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(Blank Page)
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SECTION 3 - INSTALLATION/OPERATION
3-1. Unpacking
The 199 DPU should be inspected at time of unpacking to detect any damage
that may have occurred during shipment.
NOTICE: The instrument was checked for accuracy at the factory — do not
change any of the settings during examination or accuracy will be affected.
NOTICE: For application in critical media, requiring special cleaning pro-
cesses and precautions, a polyethylene bag is used to protect the instrument
from contamination. This protective bag should be removed only under
conditions of controlled extreme cleanliness.
NOTICE: Do not locate the instrument near vents or bleed holes that dis-
charge corrosive vapors or gases.
3-2. Mounting
A. Flush or Panel Mounting
Attach the case of the instrument (recorder, indicator etc.) to the panel.
Refer to the Installation and Operation Manual for the specic instrument
for the mounting details.
B. Pipe Mounting
Refer to the Outline Dimension Drawing in Section 6 for the pipe mount-
ing diagram. The DPU must be mounted approximately level to operate
properly.
3-3. Piping — Standard Practices
A. All Applications (ow and liquid level)
1 . Shorten the distance between the primary device and the DPU as
much as possible. Distances exceeding 100 feet are not recommended.
For distances up to 50 feet, use 1/4-inch or 3/8-inch pipe or tubing.
For runs of 50 to 100 feet, use 1/2-inch pipe or tubing. The recom-
mended limitation does not apply if an air purge or blow-back system is
used.
2. Slope all piping at least one inch per linear foot to avoid liquid or gas
entrapment.
3. Provide two feet of uninsulated piping between the DPU and the pri-
mary device for each 100°F (+37.8°C) in excess of +200°F (+93.3°C).
4. Assure that the temperature of the DPU never exceeds 180°F
(+82°C). When steam tracing is necessary, the steam pressure should
not exceed ve pounds per square inch and insulation should not be
used. If pressure must exceed ve pounds per square inch, limit the
length of tubing around the DPU to two turns and do not insulate.
5. Install a suitable pulsation dampening device upstream of the DPU.
Where severe pulsation is present, the accuracy of the ow measure-
ment will be affected.
6. Mount the DPU on a solid support to minimize vibration. Tighten all
points, using a suitable compound; leaks in piping can cause measure-
ment errors.
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3-3. Piping — Standard Practices (Cont.)
7. Rotate the housing as necessary to place the connection in the proper
position. The DPU has connections in the pressure housings to accom-
modate various pipe sizes (refer to Section 6- Drawings).
8. Install a valve manifold connecting the DPU and the source of differen-
tial pressure to facilitate operation and checking of the DPU.
9. Locate all shutoff valves and bypass valves to be readily accessible from
the front of the instrument. Locate block valves at the source of dif-
ferential pressure.
B. Flow Applications
Assure that the DPU high-pressure housing is connected to the upstream
tap of the primary device.
NOTE: To prevent overheating the DPU during blowdown, the operator
should monitor the temperature by placing his hands on the pipe between
the DPU and the manifold pipe containing the vent valves.
C. Liquid Level Applications
The process media may be used as a reference leg seal uid when it is of a
type that will condense in the reference leg under all conditions.
If the process or process media characteristics are such that the above con-
ditions cannot be met, a special reference leg seal uid will be required. The
special seal uid media characteristics are such that the above conditions
cannot be met, a special reference leg seal uid will be required. The special
seal uid must not be volatile and must not be miscible with the process
media. Also, the difference in the densities of the special seal uid and the
process media will require compensation in calculating the differential pres-
sure range of the DPU.
WARNING
EXPLOSION HAZARD. ORGANIC COMPOUNDS, OIL, GREASE,
DIRT, OR SCALE OF ANY KIND CANNOT BE TOLERATED IN AN
OXYGEN INSTALLATION.
3-4. General Startup Practice Considerations
Observe the following practices when starting up an instrument.
1. Always start with the block valves closed.
2. Perform a zero check on the instrument as follows.
NOTICE: For gas service, it is recommended that zero check be performed
with both block valves closed. If the gas ow is pulsating, there may be a
standing wave effect in the process line which can displace the indicator
and appear as a zero error.
a. Open the bypass valve(s), then open one shutoff valve. This proce-
dure equalizes the pressure between both sides of the instrument. The
instrument should indicate zero.
b. If the instrument does not indicate zero, check for gas or liquid entrap-
ment in the lines or in the DPU (depending on the orientation of the
piping layout and service).
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