Powers 595 Series 11 Self-Operating Temperature Regulators - Type WM 3-Way Water Mix - Manual (Page 3)

3
ment AE-1—“Valve Selection and Sizing”—for further recommen-
dations.
Maximum Operating Pressure Differential (differential for fluid
flow): In order for the process medium to flow, a pressure drop
must exist across the valve. “Pressure differential” is the difference
in valve pressure between the inlet and outlet under flow condi-
tions. The greater the differential, the greater the flow at any given
plug position.
Though the regulator should be sized for actual conditions, you
need to know the available differential at maximum flow. For opti-
mum control, take as much differential as possible across the
valve.
Refer to Maximum Water Capacities tables on page 4.
PRODUCT IDENTIFICATION
SIZING AND SELECTION
Proper sizing of the Regulator is essential for correct system oper-
ation. An undersized Regulator will not allow sufficient flow at max-
imum load. An oversized Regulator may cycle and will not utilize
the full valve stroke for efficient modulation of flow. This results in
poor control and shortened valve life (quicker deterioration of valve
disc and seat). For these reasons, the correct sizing of the
Regulator for actual expected conditions is considered essential
for good control.
Note: Select temperature range (see page 14) with the set point in
the upper third for best valve performance.
Size the #11 Regulator for actual rather than maximum conditions.
DO NOT size according to pipe size; piping systems are designed
for different criteria than process controls. Refer to Powers docu-
SPECIFICATIONS
Valve Sizes
1/2", 3/4", 1", 1-1/4", 1-1/2", 2" 2-1/2", 3", 4"
Valve Plug Travel See table on page 10 See table on page 10
Effective Bellows Area 7.8 sq. in. (50.3 sq. cm.) 7.8 sq. in. (50.3 sq. cm.)
Body Material Bronze Cast Iron
Body Rating ANSI Class 125 ANSI Class 125
Connections Screwed Ends Flanged Ends
Style Composition Disc Bronze Trim
Max. Body Temperature 400°F (204°C) 350 °F (177°C)
Temperature Range See bulb spec on page 13 See bulb spec on page 13
Controlled Medium Water Water
Max. Differential Pressure See Tables on pp. 3 & 4 See Tables on pp. 3 & 4
Max. Allowable Overheat Temp. 25°F (14°C) above temp. range 25°F (14°C) above temp. range
Max. Well Safe Pressure See Tables on page 11 See Tables on page 11
Max. Body Pressure 125 psig 125 psig
Shipping Weight See Table on page 10 See Table on page 10
Flow Characteristics Linear Linear
Shutoff Class Rating ANSI Class IV ANSI Class III
Leakage <0.01% of rated valve capacity <0.1% of rated valve capacity