Before installing this product, become familiar with the installation instructions presented in Section 3. In addition, adhere to the following safety
precautions:
Pressure – The instrument shall not be subjected to pressure higher than the
safe working pressure stamped on the pressure housings.
Corrosion – The bellows and O-rings of the sensors shall not be subjected to
media incompatible with ethylene propylene and 316 stainless steel.
Vibration and Shock – The instrument shall not be subjected to severe mechanical vibration or hydraulic shock.
stances that can lead to personal injury or death, property damage, or
economic loss.
CAUTION: Indicates actions or procedures which if not performed correctly
IMPORTANT: Indicates actions or procedures which may affect instrument operation or
may lead to personal injury or incorrect function of the instrument
or connected equipment.
may lead to an instrument response that is not planned.
2
Model 351/352/353 Liquid Level Systems Section 1
Section 1— Introduction
General
The Barton Liquid Level System provides accurate hydraulic transmission of
a process medium for measuring the level of liquids contained in a process
vessel. The self-contained system is typically mounted outside the vessel.
Floats, levers, pins, and other mechanical devices susceptible to contamination or wear are not required. Because the basic system is actuated by the
process media, local indication is possible without external power.
Barton Liquid Level Sensors can be purchased as a component of a factory-
built system, or as a part for a eld-installed system. Sealed sensor systems
can be designed in the following congurations:
• a single sensor system (Model 351)
• a dual-sensor system (Model 352)
For applications involving corrosive uids or tank temperatures above 200°F
(95°C), a dual-sensor conguration is recommended.
For applications involving unusual ll requirements due to liquid volumes or
high ambient temperatures, a Model 353 system is recommended. The Model
353 system can be designed with one or two sensors. See Model 353 Liquid
Level System on page 5 for details.
Process vessel
Single sensor
DPU
(shown
with
indicator)
Single-Sensor System
Figure 1.1—Single-sensor and dual-sensor system congurations
IMPORTANT: In this manual, the term “sensor,” refers to a mechanical bellows as-
sembly and its pressure housing used to detect and transmit a hydraulic
or pneumatic signal to an electronic transmitter, mechanical indicator or
switch.
Sensor
Sensor
Dual-Sensor System
3
Section 1 Model 351/352/353 Liquid Level Systems
Product Description
Model 351 Liquid Level System
The Model 351 consists of a single reference sensor connected by capillary
tubing to a Barton Differential Pressure Unit (DPU). Hydraulic uid is sealed
inside the sensor and the capillary tubing, eliminating the need for additional
piping.
The Model 351 system, as shipped from the factory, needs only to be mounted on the vessel to provide continuous level measurement when used with a
Barton readout instrument. The sensor can be installed on vented or sealed
process vessels. The readout instrument (DPU, for example) can be installed
at various elevations (i.e., below the vessel, at the vessel upper connection or
above the vessel ) as long as the instrument calibration considers the elevation
difference between the instrument and the sensor.
Model 352 Liquid Level System
The Model 352 consists of two reference sensors connected by capillary tubing to a Barton DPU.
Unlike the Model 351 system, the process media does not come into contact
with the DPU, making the model ideal for applications involving corrosive
liquids or tank temperatures above 200°F (95°C).
The DPU can be mounted up to 50 ft (15 meters) away from the vented or
sealed process vessel and at ele vations up to 30 ft (9 meters) above the lowest
sensor. Elevation of the readout instrument (DPU) with respect to the sensors
is essentially unlimited as long as the instrument calibration considers the
elevation difference between the two sensors.
Model 351/352 System Sensors
A Model 351 or Model 352 system can include any of three sensor types,
depending on the pressure rating required:
• 500-psi SWP sensor (referred to as Model 351 sensor throughout this
document)
• 3,000-psi SWP sensor (referred to as Model 351 sensor throughout this
document)
• No-pressure-rating sensor (referred to as Model S048 sensor throughout
this document)
All three sensor types contain a 3.75” (95 mm) bellows that functions as a
seal. As pressure on the bellows varies due to changes in liquid level and/or
process system pressure variations, these pressure variations are transmitted
through the liquid lled sensor and capillary tubing to the readout instrument.
4
Model 351/352/353 Liquid Level Systems Section 1
The S048 sensor is constructed with the same housing as the 500-psi SWP sensor for mounting purposes, but has no pressure rating and is designed to mount
inside open ves sels or sumps. The large bottom opening of the sensor prevents
fouling of the sensor ports due to dirt, loose debris, or other contamination.
Model 353 Liquid Level System
The Model 353 system is designed specically for unusual ll liquid requirements due to liquid volumes or high ambient temperatures.
A Model 353 system can be designed with one or two sensors. Systems are
typically assembled in the eld.
The Model 353 high-volume sealed sensor is rated for a 3,000-psi SWP and
contains a single removable bellows with an initial volume of 10 in.³ (164
cc). The bellows is 2.25 in. (57 mm) long and has a diameter of 3.75 in. (95
mm). It can extend an additional 1 in. (25 mm), adding an additional 7.5 in.³
(123 cc) to its volumetric capacity (see Figure 1.2). When the bellows is fully
compressed, an internal valve closes to prevent the escape of process uids.
The bellows may be removed for replacing a dam aged bellows or for pressure
testing the capillary tubing.
All sensors have stainless steel housings. Capillary tubing connecting the sensor to the DPU is either 1/4-in. or 3/16-in. OD. Tubing length is deter mined
by the installation. Capillary tubing may be bent or looped as required. A
1/4-in. NPT plug or a high-pressure tting (3/8-in. OD tubing) in the housing
facilitates venting.
5
Section 1 Model 351/352/353 Liquid Level Systems
Specications
Specications for Barton sealed sensor systems are presented in Tables 1.1
and 1.2.
CAUTION: Never operate the system at pressures exceeding the safe working
lower. Periodic testing at pressures up to 150% of the safe working
pressure is permitted, provided the pressure is applied equally and
simultaneously to the entire system.
Table1.1—SensorSpecications
SpecicationModel S048Model 351Model 353
Housing Material316 SST316 SST316 SST
Safe Working PressureN/A500 or 3000 psi
(3.5 or 20.7 MPa)
Bellows Material
Housing Seals
Bellows Volume
Nominal3.5 in.³
Thermal Expansion
Bellows SealsO-rings O-ringsO-rings
316L SST316L SST
N/AO-ring & Backup
(57.4 cc)
N/AN/A
O-ring
3.5 in.³
(57.4 cc)
3000 psi
(20.7 MPa)
316L SST
O-ring, Backup
O-ring, and Flat
Nickel Gasket
10 in.³
(165 cc)
17.5 in.³
(288 cc)
Table1.2—CapillarySpecications
Specication1/4-in. OD3/16-in. OD
Material316 SST304L SST
Outside Diameter¼ in. (6.4 mm)3/16 in. (4.8 mm)
Wall Thickness0.060 in. (1.5 mm)0.049 in. (1.2 mm)
Capillary Armor Material302 SST316 SST
Capillary Fill MaterialSilicone Oil, Water, Ethylene
Silicone Oil, Water, Ethylene
Glycol & Water or Mineral Oil
6
Model 351/352/353 Liquid Level Systems Section 2
Section 2—Theory of Operation
General
A uid column exerts a pressure proportional to its height and density, independent of the shape or volume of the containing vessel. A differential pres-
sure unit (DPU) can be calibrated to indicate the height of a uid when the
uid density is known. In tanks of given dimensions, the weight and volume
of contents can be measured by a DPU.
One or two sealed sensors are connected to the DPU by capillary tubing.
These sensors contain bellows which function as “isolation seals.” As pressure on the sensor bellows varies due to changes in liquid level, the variations
are transmitted hydraulically through the tubing to the bellows of the DPU.
Model 351/Model S048 Sensors
The pressure deection characteristics of the Model 351 (500-psi or 3,000psi) and Model S048 sensor bellows are shown in Figure 2.1.
Figure 2.1—Pressure deection characteristics of the Model 351/352 sensor bellows
Model 353 Sensor
In the event of thermal expansion of the ll-liquid in the capillary tubing
and in the other instruments, the Model 353 sensor bellows can extend 1 in.
(25 mm) for 7.5 in.³ (123 cc) displacement. If leakage occurs in the capillary
tubing, the bel lows becomes compressed approximately 0.56 in. (14 mm) and
7
Section 2 Model 351/352/353 Liquid Level Systems
then closes an internal valve to prevent further loss of bel lows liquid. This
action prevents escape of process liquid.
The sensor bellows may be removed with a special wrench (see Table 4.1 and
Figure 4.1, page 14). This permits pressure testing and leak testing of the hous-
ing and capillary tubing and allows damaged parts to be replaced before the
system is lled.
The pressure deection characteristics of the Model 353 sensor bellows are
shown in Figure 2.2.
1 in. (25 mm)
Normal length
2.25 in. (57 mm)
Travel to
fully close valve
0.84 in. (21 mm)
Figure 2.2—Pressure deection characteristics of the Model 353 sensor bellows
The bellows can extend over 1 in. (25 mm) to accommodate ll uid expansion under hot operating conditions. As seen in Figure 2.2, the expansion
creates an internal pressure of 25.7 in. H2O (6.4 kPa) at 1 in. (25 mm). When
compressed, the bellows travels approximately 0.5 in. (13 mm) before the
internal valve begins to close. Compression of the bellows to 0.5 in. (13 mm)
requires approximately 10 in. H2O (2.6 kPa) of external pressure.
8
Model 351/352/353 Liquid Level Systems Section 3
Section 3—Installation
Unpacking
All instruments are inspected during manufacture and prior to shipping. However, an inspection should be performed at the time of unpacking to detect
any damage that may have occurred during shipping.
When unpacking, carefully remove the instrument from the container. If the
instrument is a liquid-lled sys tem, remove the strap-fasteners and gently
unrollthe capillary tubing.
The transmitter output may indicate “Near Full Scale” if the system is tested
prior to installation. This is nor mal, and the transmitter output will be correct
when the reference leg is elevated.
Model 353 Sensor Assembly
The Model 353 sensor bellows and bottom plate bolts are not torqued to
installation requirements as shipped. See Section 4 on page 13 for instructions on removal and replacement of Model 353 sensor bellows.
Mounting
Mount the sensors as close to vertical orientation as possible to ensure proper
operation. The sensor may be oriented with the vent pointed up or down,
depending on the service or installation design.
When mounted with the L-bracket, mount the sensors with three 3/8-16 SAE
bolts, Grade 5 or better, torqued to 24 to 26 ft-lb (33-35 N-m). The mounting bracket may be rotated axially or reversed, as required for installation (as
shown in dimensional drawings in Section 6).
Interfacing process tubing should be supported to minimize relative motion
between the sensor and connections. The capillary tubing should be supported
with at least one support located within 1 ft (0.3 meters) of the sensor. The
minimum bend radius of the capillary tubing is 2 in. (50 mm).
Piping and Installation
IMPORTANT: Sealed systems are normally lled at the factory, but can be installed and
lled in the eld.
Sensors should be connected in accordance with user specications. Flanges
and tube ttings (3/8”, 1/2” or 3/4”) are available for this purpose.
9
Section 3 Model 351/352/353 Liquid Level Systems
Capillary Tubing Welding
Figures 3.1 through 3.3 present the information and procedures necessary to
weld the capillary tubing and tubing coupling.
Figure 3.1—1/4-in. OD capillary tubing welds
IMPORTANT: All parts are solution annealed 316 or 304 stainless steel. Please adhere
10
to the following welding practices:
(1) Weld type: GTAW llet, 45 amps, 10 volts, 20 CFH (9.5 l/m) Argon
gas ow.
(2) Use 1/16” dia. Type 308 ller rod
Model 351/352/353 Liquid Level Systems Section 3
Figure 3.2—3/16-in. OD capillary tubing welds
IMPORTANT: All parts are solution annealed 304L stainless steel. Please adhere to the
following welding practices:
(1) Weld type: GTAW llet, 45 amps, 10 volts, 20 CFH (9.5 l/m) Argon
gas ow.
(2) Use 1/16” dia. Type 308 ller rod
11
Loading...
+ 25 hidden pages
You need points to download manuals.
1 point = 1 manual.
You can buy points or you can get point for every manual you upload.