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
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 contained in a process vessel.
For process ow measurements, the DPU is connected across a primary device
(a venturi, an orice 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
pressure housings. The dual
bellows assembly consists of two
opposing internally connected liquid-lled bellows, a center plate,
range springs, overrange valves,
and a torque tube assembly.
The pressure housings are connected by Pipe or tubing to the
primary device located in the system piping. Variations in differen-
Torque Tube
Shaft
Mounting
Bracket
Venting
Connection
Pressure
Connection
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 motion actuates the mechanism of the process monitoring instrument.
The process monitoring instrument that is connected to the torque tube assembly may be an indicator, a switch, a transmitter, a recorder, or other process
control device.
1-3. Specications
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
3
5
)
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
)
Available DP Ranges
0-10" w.c. to 0-400" w.c.
(0-25 mbar to 0-993 mbar
)
-
.
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.
0-15 psi to 0-100 psi
(0-1 bar to 0-6.9 bar
Table 1-1. Model 199 DPU Material/Range Specications
)
Body Housing Material
Cast Aluminum 356T6
Forged Stainless Steel 316
Forged Steel AISI C1018
(For NACE Service
Forged Steel AISI C1018
Forged Stainless Steel 316
Forged Alloy Steel 4142
Forged Alloy Steel 4142
Forged Stainless Steel 17-4 PH
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)
)
)
)
psi
SWP
)
(bar
)
(69
1,000
NACE
(138)
2,000
(172
2,500
(207
3,000
4,500
(310
)
(414
6,000
Net
Volume
in cu. in.(cc)
4
0.5" (8.2 cc) 1.5" (25 cc) 0.5" (8.2 cc) 1.5" (25 cc)
l
Displacement in cu. in.(cc) for full-scale
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
trave
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-
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 specied to meet NACE MR-01-75 (Rev. 80). Metric conversions are approximate. Outline dimension drawings available upon request
SECTION 2 - THEORY OF OPERATION
2-1. Basic Components (See Figure 2-1)
Torque Tube
Shaft
HP Bellows
Center Plate
Torque Tube
LP Bellows
Range Spring
HP Over-
range Valve
Temperature
Compensator
HP Housing
Damping Valve Plug
Valve Stem
LP Housing
LP Overrange
Valve
Housing
Bolts
Pulsation Damper
Figure 2-1. 199 BUA Cutaway
A. Pressure Housings
The two pressure housings of the Model 199 DPU are available in the various safe working pressure ratings dened 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).
5
7
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
Torque Tube Gland Nut
(DO NOT LOOSEN)
Torque
Tube
Shaft
2-1/8" Bellows Unit Assembly (BUA)
Range
Springs
Screws
Lock
Nu
t
Range
Spring
Assembly
Push
Rod
.
Drive Arm
Hole Plug
(DO NOT LOOSEN)
Torque Tube Gland Nut
(DO NOT LOOSEN)
Torque
Tube
Shaft
3-3/4" Bellows Unit Assembly (BUA)
Range
Springs
Spring
End Cup
Spring Post
Range Spring
Assembly
Retainer Nut
Push Rod
Lock
Nut
Figure 2-2. Bellows Unit Assemblies (BUAs)
6
D. Torque Tube Assembly
O-Ring Seal
Torque Tube
Lock Nut
Torque Tube
Torque Tube
Shaft
Center Plate
Needle Beaing
Weld
8°
Rotation
Weld
Ball Bearing
Minature
Precision
Ball Bearing
Valve Stem
Drive Arm
Valve Stem
Disc
0.200"
Bellows Travel
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.
7
9
(Blank Page)
8
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 processes 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 discharge 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 specic instrument
for the mounting details
B. Pipe Mounting
Refer to the Outline Dimension Drawing in Section 6 for the pipe mounting 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
2. Slope all piping at least one inch per linear foot to avoid liquid or gas
3. Provide two feet of uninsulated piping between the DPU and the pri-
4. Assure that the temperature of the DPU never exceeds 180°F
5. Install a suitable pulsation dampening device upstream of the DPU.
6. Mount the DPU on a solid support to minimize vibration. Tighten all
.
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
.
entrapment
mary device for each 100°F (+37.8°C) in excess of +200°F (+93.3°C).
(+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
Where severe pulsation is present, the accuracy of the ow measure
ment will be affected.
points, using a suitable compound; leaks in piping can cause measure
ment errors.
.
.
.
.
-
.
-
-
9
1
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 differential 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 conditions 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 pressure 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)
10
.
.
.
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