Powers 595 Series 11 Self-Operating Temperature Regulators - Type ST Stainless Trim User Manual

Technical instructions

IS-P-595ST

Table of Contents

■

Valve Description ................................................................1
Operation ..............................................................................1
Applications .........................................................................2
Speciﬁ cations ......................................................................2
Water Capacities ...............................................................3
Sizing and Selection ...........................................................3
Steam Capacities ................................................................4
Product Identiﬁ cation ........................................................5
Installation ............................................................................5
Maintenance ........................................................................6
Valve Seat Removing Tool ................................................8
Preventive Maintenance...................................................9
Troubleshooting ............................................................9, 16
Dimensions .........................................................................10
Parts List .............................................................................12
Accessories .......................................................................14
Temp. Ranges/Bulb Sizes ...............................................14
Order Code .........................................................................15
Warranty Information ......................................................16

#11 Regulator

Single Seat - Stainless Steel Trim (Type ST)

Valve Description

■

The Powers #11 Stainless Steel Trim Regulator is a self-actu-
ating control valve which automatically controls the tempera-
ture of a ﬂ uid without the use of external power. The SST
Regulator is speciﬁ cally designed for high pressure steam
applications requiring positive shutoff. 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 contain-
ing 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 tub-
ing walls to ensure long operating life.

The Powers #11 ST Regulator features:
• Stainless steel valve plug and seat ring withstand high tem-

peratures

• Tight shutoff when the valve is closed
• A valve stem of highly polished corrosion resistant grade

316L stainless steel to decrease friction and reduce hyster-
esis

• 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
responsive ﬂ uid. The bulb is inserted into the 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 ther-
mally 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.

(B)

(D)

(A)

(C)

Technical Instructions