Ashcroft 311, 312 Specifications

Data Sheet

311/312 All-Welded Midi Threaded Seals

FEATURES

 All-welded construction  No gaskets or bolts  Large diaphragm allows for use with 4½˝ gauges  Compact and light weight alternative to larger seals

TYPICAL USES

 Oil and Gas  Reﬁneries  Chemical and Petrochemical  Water and Wastewater  NACE Compliant Processes (Sour Gas Separation)  Biogas and Biodiesel

312/311

Threaded Seal

SPECIFICATIONS

Connection style: 311: All-Welded

312: All-Welded with ﬂushing connection

Process Connection: 311: ¼ to 1 NPT Male or Female

312: ¼ or ½ NPT Female Instrument Connection: ¼ or ½ NPT Female

Fill Fluid: See table 1 on page 2

Approvals: CRN

WETTED COMPONENTS

Diaphragm Bottom Housing

316L SS, Hastelloy® C-276, Tantalum 316L SS, Hastelloy® C-276

NON-WETTED COMPONENTS

Top Housing

316L Stainless steel

KEY BENEFITS

• Protects instruments from corrosive media

• Stainless top housing stands up to corrosive environments

• Prevents pressure instruments from clogging

All speci ﬁcations are subject to change without notice.

All sales subject to standard terms and conditions.

ashcroft.com

[email protected]

1.800.328.8258

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Data Sheet

311/312 All-Welded Midi Threaded Seals

TABLE 3 - FILL FLUIDS

Fill Fluid Temperature

Viscosity

(cSt at 70ºF (21ºC))

Glycerin (food grade) 0°F to 400°F (-18°C to 204°C) 1,300 CG

50 cSt Silicone -40°F to 500°F (-40°C to 260°C) 50 CK

10 cSt Silicone -40°F to 500°F (-40°C to 260°C) 10 DJ

Halocarbon® 4.2 -70°F to 300°F (-57°C to 199°C) 4.2 CF

Slytherm® 800 -40°F to 750°F (-40°C to 400°C) 10 HA

Variation

Code

Notes

Direct-mounting only. Not for use with vacuum service

For use with oxygen/ oxidizing process media

High temperature applications

Syltherm® XLT -150°F to 500°F (-100°C to 260°C) 1.4 CC

Calﬂo® AF -20°F to 600°F (-29°C to 316°C) 60 KF

Mineral Oil 10°F to 400°F (-12°C to 204°C) 75 MY

Neobee® M-20 (food grade) 5°F to 400°F (-15°C to 204°C) 9.5 NM

Silicone (food grade) -40°F to 500°F (-40°C to 260°C) 350 CZ

Distilled Water 40°F to 185°F (4°C to 85°C) 0.9 FJ

50/50 Glycerin/Water 15°F to 200°F (-9°C to 93°C) 30 GH

Propylene Glycol -50°F to 325°F (-46°C to 163°C) 54 CV

Ethylene Glycol 20°F to 325°F (-7°C to 163°C) 14 FK

50/50 Ethylene Glycol/Water -25°F to 190°F (-32°C to 88°C) 2.9 CT

80/20 Glycerin/Water 15°F to 225°F (-9°C to 107°C) 270 GR

95/5 Water/Propylene Glycol 40°F to 185°F (4°C to 85°C) 1.0 PY

Low temperature applications

High temperature, silicone-free

All speci ﬁcations are subject to change without notice.

All sales subject to standard terms and conditions.

ashcroft.com

[email protected]

1.800.328.8258

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Data Sheet

311/312 All-Welded Midi Threaded Seals

ORDERING CODE Example:

Process Connection Size

02 - ¼ NPT Male (available for 311 only) 02 04 - ½ NPT Male (available for 311 only) 06 - ¾ NPT Male (available for 311 only) 08 - 1 NPT Male (available for 311 only) 25 - ¼ NPT Female 50 - ½ NPT Female 75 - ¾ NPT Female (available for 311 only) 10 - 1 NPT Female (available for 311 only)

Se a l Ty p e

311 - Threaded All-welded midi seal no ﬂushing port 312 - Threaded All-welded midi seal with ﬂushing port 312

Diaphragm Material

S - 316L Stainless steel S U - Tantalum H - Hastelloy® C-276

Bottom Housing Material

S - 316L Stainless steel S H - Hastelloy® C-276

Instrument Connection Size

02T - ¼ NPT Female 02T 04T - ½ NPT Female

Options (if choosing an option(s) must include an “X”)

Fill Fluid (See Table 1 on page 2 for more available ﬁll ﬂuids)

CK - 50 cSt Silicone CK

Optional Features

PU - Pipe plug for ﬂushing connection (plug will match bottom housing material; 312 seal only) NH - Stainless steel instrument NH DU - Instrument welded to seal (instrument must be of like-material to top housing) MQ - Positive material identiﬁcation W1 - Dye penetrant testing 6B - Cleaned for oxygen service

02 312 S S 02T XCK NH

X__

All speci ﬁcations are subject to change without notice.

All sales subject to standard terms and conditions.

ashcroft.com

[email protected]

1.800.328.8258

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A

Data Sheet

311/312 All-Welded Midi Threaded Seals

DIMENSIONS in

For reference only, consult Ashcroft for speciﬁc dimensional drawings

[ ]

are millimeters

311/312 MIDI DIAPHRAGM SEAL -THREADED

(WITH & WITHOUT FLUSHING CONNECTION)

B

Bottom of Housing to C of 1/8 NPT

L

Flushing Port

D

(Type 312 only)

C

Model A B C D

311MIDI DIAPHRAGM SEAL -THREADED

MALE PROCESS CONNECTION

B

C

311/312 2 [51] 2.65 [67] 0.94 [24] 0.94 [24]

311

(male connection)

2 [51] 13⁄8 [35] 1¾ [44] -

All speci ﬁcations are subject to change without notice.

All sales subject to standard terms and conditions.

ashcroft.com

[email protected]

1.800.328.8258

4 of 4