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Matching the valve¹s body material and end connection to
existing piping or specifications is the best choice.
Otherwise, to determine what body material and end
connection you need, you must first know the pressure
and temperature of the medium entering your valve. For
most flowing media you will need an approximate idea of
the temperature. For saturated steam you can use the
steam table below to determine the temperature. Once you
know the pressure and temperature, you can use the body
pressure-temperature rating table, (to right, to
determine what body material and end connection you
need. |
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You need a 2-1/2 inch single-seated valve. You have
saturated steam entering your valve at 100 PSIG. From
the steam table you see the steam has a temperature of
337.9°F. From the valve configuration sheets you know
that a 2-1/2 inch single-seated valve is available with
an iron body with a 125 flange or an iron body with a
250 flange. Scanning the pressure-temperature rating
table, you see that the pressure rating for an iron body
with a 125 flange at 337.9°F is not listed but a
pressure rating is listed at 350°F. At 350°F the
pressure rating is 125 PSIG. Since 350°F exceeds the
actual temperature of 337.9°F and the 125 PSIG rating at
350°F exceeds the actual pressure of 100 PSIG, an iron
body with a 125 flange is ok. |
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You need a 6 inch double-seated valve. You have 200 PSIG
water entering your valve at 175°F. From the valve
configuration sheets you know that a 6 inch double
seated valve is available with an iron body with a 125
flange or an iron body with a 250 flange. Scanning the
pressure-temperature rating table, you see that the
pressure rating for an iron body with a 125 flange at
175°F is 170 PSIG. Since this pressure rating is less
than the actual pressure rating of 200 PSIG, an iron
body with a 125 flange is not ok. Scanning the
pressure-temperature rating table again, you see that
the pressure rating for an iron body with a 250 flange
at 175°F is 385 PSIG. Since this 385 PSIG rating is
greater than the actual pressure of 200 PSIG, an iron
body with a 250 flange is ok. |
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