Powers 595 Series 11 Self-Operating Temperature Regulators - Type DB & DS Double Seat, Balanced - Manual

Technical Instructions
IS-P-595DB
Double Seat - Balanced Valve - Bronze (Type DB)
or Stainless Steel Trim (Type DS)
Description
■
The Powers #11 Double Seat Balanced Valve Regulator (Bronze
or Stainless Steel trim) is a self-actuating control valve which auto-
matically controls high temperature fl uids at high pressures with-
out the use of external power. Adjust the set point and the rugged
self-operating #11 Regulator controls the fl ow of heating or cooling
medium (water or steam) to maintain a constant temperature.
The instrument has a vapor pressure thermal system containing
a thermally responsive fl uid. This thermal system rapidly senses
temperature changes at the bulb and accordingly positions the
valve plug, to regulate the fl ow of the heating or cooling medium
to maintain a desired temperature. The thermal system features a
two-ply brass bellows with six reinforcing ribs on the bellows head
and thick capillary tubing walls to ensure long operating life.
The Powers #11 DS and DB Regulators feature:
• A double seated valve for handling high capacities
• A valve stem of highly polished corrosion resistant grade 316L
stainless steel to decrease friction and reduce hysteresis
• An adjusting nut mounted on ball bearings and a set point
adjusting rod to ease set point adjustments
• A set point reference scale to aid temperature adjustments
Operation
■
A bulb is connected to a bellows containing a thermally respon-
sive fl uid. The bulb is inserted into fl uid you are trying to control
(process fl uid) to sense its temperature. The Regulator set point
is adjusted to allow suffi cient fl ow of heating or cooling medium
(water or steam) through the valve to keep the process fl uid at
the desired temperature.
Direct Acting (heating application)
(A) When the temperature of the process fl uid drops below
the set point, the temperature of the thermally responsive
fl uid decreases, which decreases the vapor pressure in the
bulb/bellows. The force of the resulting vapor pressure is less
than the spring force, so the bellows contract and the spring
extends, which raises the valve plug up from its seat. This
increases the fl ow of the heating medium (water or steam),
which raises the temperature of the process fl uid.
(B) As the process fl uid temperature increases toward or
beyond the desired set point, the temperature of the thermally
responsive fl uid in the bulb increases, which causes the vapor
pressure to increase. This expands the bellows, compresses
the spring, and moves the valve plug down and closer to its
seat, to reduce or stop the fl ow of the heating medium.
Reverse Acting (cooling application)
(C) When the temperature of the process fl uid rises toward or
above the set point, the temperature of the thermally respon-
sive fl uid increases, which increases vapor pressure in the
bulb/bellows. The resulting force of the vapor pressure is
greater than the spring force, so the spring contracts and the
bellows expand to push the valve plug downward, away from
its seat. This increases the fl ow of the cooling medium, which
lowers the temperature of the process fl uid.
VAPOR
Thermally
Responsive
Fluid
BULB
CAPILLARY
TUBING
SPRING
BELLOWS
Thermally
Responsive
Fluid
VALVE PLUG SEATS
DIRECT ACTING
VALVE PLUG SEATS
Temp.
Below
Set Point
Temp.
Above
Set Point
REVERSE ACTING
VALVE
PLUG
VALVE
PLUG
VALVE
PLUG
VALVE
PLUG
(D) (C)
(A)
(B)
1
Table of Contents
■
Valve Description ......................................................... 1
Operation ....................................................................... 1
Applications .................................................................. 2
Specifi cations ............................................................... 2
Sizing and Selection .................................................... 3
Water Capacities ........................................................ 3
Steam Capacities ......................................................... 4
Product Identifi cation ................................................. 5
Installation ..................................................................... 5
Maintenance ................................................................. 6
Preventive Maintenance.......................................... 10
Troubleshooting ......................................................... 10
Parts .............................................................................. 11
Dimensions .................................................................. 14
Accessories ................................................................ 16
Temp. Ranges/Bulb Sizes ........................................ 16
Order Code .................................................................. 17
Warranty Information ............................................... 18