Model
763 External Cage Level Switch
for
Very High Pressure and Temperature
Steam and Heating Fluid Service
Download
the Series 700 Detailed Datasheet in Acrobat Format
The
Delta Controls Model 763 is specially intended
for the really tough applications found in boiler houses and heating facilities.
Typical uses include steam drum level and drip leg services. Various element
styles are utilized so as to produce the most reliable operation under the
specific service conditions. Dual magnets are standard in all models. They
provide reliable and positive switching. They also make the units immune to
the vibration-induced false alarms and shutdowns.
- Switch Action:
Single point alarm
- Specific Gravity:
0.3 to 2.4 units
- Interface Differential:
0.1 unit minimum
- Temperature:
-350 to 1100°F
- Pressure: -15
to 6000 PSIG
- Process Connection:
1", 1 ½", or 2" butt, stub, or socket weld; ANSI flanges
or Greyloc hub
Model 763-36
& -37 External Cage Level Switch
for Very High
Pressure and Temperature Heating Service
Displacer Sensor,
One Alarm Point
OPERATION
The Delta
Controls Models 763-36 and -37 provide output switching at a single
elevation of a varying liquid level (usually steam condensate). The unit
is mounted outside the process vessel. The external cage design is utilized
to minimize process turbulence effects and in order that the level control
may be valved off from the process vessel and depressurized for testing
and maintenance, without disturbing the operation of the process.
The vertical counterweight is
inside the cooling extension tube. It also offsets most of the weight of
the heavy wall displacer; which allows operation in low SPG liquids at high
vapor pressures. The displacer sensor moves up and down as the liquid level
varies. The counterweight,, with drive magnet, is connected across the pivot
shaft from the sensing element. The drive magnet is located on top of the
counterweight and also moves up and down. The drive magnet is continuously
coupled to the switch station magnet by their respective magnetic fields.
The magnetic lines of force pass through the nonmagnetic barrier web and
connect the two magnets. The magnets poles are in opposition. When the drive
magnet moves past the centerline of the station magnet; the magnetic repulsive
force causes the station magnet to be driven against its stop in the opposite
direction. This snap action is positive and fast. There is never an disengaged"neutral"
position. The constantly engaged dual magnet design is insensitive to vibration.
The station magnet is connected to an output switch which actuates and deactuates
as the station magnet is alternatively driven against the two stops. The
counterweight design allows heavy (even solid) displacers to be used in
very high temperature and pressure applications.
INSTALLATION
The Delta
Controls Models 763-36 and -37 are mounted horizontally in a vertical
riser with straight through piping. The switching point band is halfway
up on the cage (at the cage horizontal centerline). This switch point may
be slightly higher or lower depending on the SPG of the process. The unit
should be mounted close to the vessel whose level is to be monitored; if
this is not possible, then slope the connecting pipes 1" per foot to
drain any sediment back towards the vessels.
Models
763-C, and -R External Cage Level Switches
for Heating Service, One Alarm Point
OPERATION
The Delya
Controls Models 763-C and -R provide output switching at a single elevation
of a varying liquid level (usually steam condensate). The unit is mounted
outside the process vessel. The external cage design is utilized to minimize
process turbulence effects and in order that the level control may be valved
off from the process vessel and depressurized for maintenance without disturbing
the operation of the process. The switch station contains a magnet and is
isolated from the process liquid by the barrier tube. The magnetic lines of
force pass through the nonmagnetic barrier tube. Output action occurs as the
attractor is lifted up into the magnetic field of the switch station magnet.
The magnet is pulled in against the barrier tube and the output switch is
actuated. The output switch stays actuated until falling liquid level lowers
the float and pulls the attractor out of the magnet's field.
INSTALLATION
The Delta
Controls Model 763 should be mounted vertically near the process vessel
containing the liquid level to be sensed. It should be positioned so that
the switching point is located at the desired liquid elevation which must
be between the upper and lower process vessel connections. Long lines connecting
the process vessel to the cage should be avoided; but when necessary, they
should be sloped 1" per foot towards the process vessel to limit sedimentation
buildup.
Model
763Y External Cage Level Switch
for Heating Service, Top/Bottom Connections
OPERATION
The Delta
Controls Model 763Y Level Alarm provides a single switching output
when the liquid level, usually steam condensate, passes the centerline of
the body. The unit has its displacer in a cage mounted outside the process
vessel. The external cage design is utilized to minimize turbulence effects
and in order that the level control may be valved off from the process vessel
and depressurized for maintenance without disturbing the operation of the
process.
The displacer sensor is held in
position by a pivot shaft. A counterweight is located on the opposite side
of the pivot shaft. The displacer moves up and down as the liquid level varies.
This action causes a rotary motion of the counterweight/element as they pivot
around the shaft. A drive magnet, embedded in the counterweight, is continuously
coupled to the switch station magnet by their respective magnetic fields.
The magnetic lines of force pass through the nonmagnetic barrier web and connect
the two magnets. The magnets' poles are in opposition. When the drive magnet
is rotated past the centerline of the station magnet; the magnetic repulsive
force causes the station magnet to be driven against its stop in the opposite
direction. This snap action is positive and fast. There is never an disengaged"neutral"
position. The constantly engaged dual magnet design is insensitive to vibration.
The station magnet is connected to an output switch which actuates and deactuates
as the station magnet is alternately driven against the two stops. The counterweight
design allows heavy displacers to be used in very high pressure and temperature
applications.
INSTALLATION
The Delta Controls Model 763Y is
mounted horizontally in a vertical riser with straight-through piping. To
change the liquid level switching point add or subtract pipe lengths above
and below the cage, then move the entire unit up or down to the desired switching
elevation. The switch point band is halfway up (on the horizontal centerline)
of the cage assembly. The switch point may be slightly higher or lower depending
upon the actual specific gravity of the process liquid and the size sensing
element.
