Diaphragm seals
Diaphragm seal with flange connection
With internal diaphragm
Model 990.26
WIKA data sheet DS 99.26
for further approvals
see page 7
Applications
■■ Aggressive, highly viscous, crystallising or hot media
■■ Process industry
■■ Small flange process connections
Special features
■■ Open flange with internal, all welded diaphragm
■■ Mounting to measuring instruments for low pressures
■■ Compact design
Diaphragm seal with flange connection, model 990.26
Description
Diaphragm seals are used for the protection of pressure The model 990.26 diaphragm seal is ideally suited for appli-
measuring instruments in applications with difficult media. In cations with small process connections. Due to the internal
diaphragm seal systems, the diaphragm of the diaphragm diaphragm low measuring ranges can be realised. The large
seal effects the separation of the instrument and the medium. diameter of the diaphragm effects a lower deviation at the
The pressure is transmitted to the measuring instrument measuring instrument when the temperature changes.
via the system fill fluid which is inside the diaphragm seal
system. Mounting of the diaphragm seal to the measuring instrument
may be made via a direct connection, for high temperatures
For the implementation of demanding customer applications, via a cooling element or via a flexible capillary.
there are a wide variety of designs, materials and system fill
fluids available. For the material selection WIKA offers a variety of solutions,
in which the upper body of the diaphragm seal and the
For further technical information on diaphragm seals and wetted parts can be made of identical or different materials.
diaphragm seal systems see IN 00.06 “Application, operating The wetted parts can, as an alternative, be coated.
principle, designs”.
WIKA data sheet DS 99.26 ∙ 11/2017 Page 1 of 7
Data sheets showing similar products:
Diaphragm seal with flange connection; model 990.27; see data sheet DS 99.27
Specifications
Model 990.26 Standard Option
Pressure range From 400 mbar (depending on diameter of diaphragm)
Level of cleanliness of wetted Oil and grease free per ASTM G93-03 ■■ Oil and grease free per ASTM G93-03 level D and
parts level E (WIKA standard) and ISO 15001 ISO 15001 (< 220 mg/m2)
(< 1,000 mg/m²) ■■ Oil and grease free per ASTM G93-03 level C and
ISO 15001 (< 66 mg/m²)
Origin of wetted parts International ■■ EU
■■ CH
■■ USA
Connection to the measuring Axial adapter Axial adapter with G 1/2, G 1/4, 1/2 NPT or 1/4 NPT (female)
instrument
Type of mounting Direct mounting ■■ Capillary
■■ Cooling element
Design per NACE - ■■ MR 0175
■■ MR 0103
Vacuum service (see IN 00.25) Basic service ■■ Premium service
■■ Advanced service
Diaphragm seal for mounting - With flame arrester and PTB certificate
to zone 0
Instrument mounting bracket - ■■ Form H per DIN 16281, 100 mm, aluminium, black
(only for capillary option) ■■ Form H per DIN 16281, 100 mm, stainless steel
■■ Bracket for pipe mounting, for pipe Ø 20 ... 80 mm,
steel (see data sheet AC 09.07)
Installation example, model 990.26 with mounted
pressure gauge
Not included Sealing
in delivery
Mating flange
Pressure gauge
Direct mounting
Diaphragm seal
d4
k
Diaphragm
(welded to diaphragm seal) D
b
Legend:
D Outer diameter of diaphragm seal
14174835.01
k Pitch circle diameter
d4 Sealing face diameter
f
b Flange thickness
f Height of raised face
Following DIN EN 1092-1
Page 2 of 7 WIKA data sheet DS 99.26 ∙ 11/2017
Process connection, flange
Standard Flange size Sealing face
Standard Option
Following DIN EN 1092-1 DN 15 Form B1 Form B2
DN 20
DN 25
Following ASME B16.5 ½" RF 125 ... 250 AA RFSF
¾"
1"
Following GOST 33259 DN 15 Type B -
DN 20
DN 25
Following JIS B2220 DN 15A RF -
DN 20A
DN 25A
Further flanges and options on request
WIKA data sheet DS 99.26 ∙ 11/2017 Page 3 of 7
Material combinations
Upper body of diaphragm Wetted parts Maximum permissible pro-
seal cess temperature ¹⁾ in °C (°F)
Stainless steel 1.4404 (316L) Stainless steel 1.4404 / 1.4435 (316L), standard version 400 (752)
Stainless steel 1.4539 (904L)
Stainless steel 1.4541 (321)
Stainless steel 1.4571 (316Ti)
Gold (wetted)
PFA (perfluoroalkoxy) coating, FDA / PTFE lining 260 (500)
PFA (perfluoroalkoxy) coating, antistatic / PTFE lining
Hastelloy C22 (2.4602)
Hastelloy C276 (2.4819) 400 (752)
Inconel 600 (2.4816)
Inconel 625 (2.4856)
Incoloy 825 (2.4858)
Monel 400 (2.4360)
Nickel 200 (2.4060, 2.4066) 260 (500)
Titanium (3.7035) 150 (302)
Titanium (3.7235)
Tantalum 300 (572)
Stainless steel 1.4435 (316L) Stainless steel 1.4435 (316L) 400 (752)
Stainless steel 1.4539 (904L) Stainless steel 1.4539 (904L)
Stainless steel 1.4541 (321) Stainless steel 1.4541 (321)
Stainless steel 1.4571 (316Ti) Stainless steel 1.4571 (316Ti)
Duplex 2205 (1.4462) Duplex 2205 (1.4462) 300 (572)
Superduplex 2507 (1.4410) Superduplex 2507 (1.4410)
Hastelloy C22 (2.4602) Hastelloy C22 (2.4602) 400 (752)
Hastelloy C276 (2.4819) Hastelloy C276 (2.4819)
Inconel 600 (2.4816) Inconel 600 (2.4816)
Inconel 625 (2.4856) Inconel 625 (2.4856)
Incoloy 825 (2.4558) Incoloy 825 (2.4858)
Monel 400 (2.4360) Monel 400 (2.4360)
Nickel 200 (2.4060, 2.4066) Nickel 200 (2.4060, 2.4066)
Titanium 3.7035 Titanium class 2 (3.7035)
Titanium 3.7235 Titanium class 7 (3.7235)
1) The maximum permissible process temperature is limited by the joining method and by the system fill fluid.
Further material combinations for special process temperatures on request
Page 4 of 7 WIKA data sheet DS 99.26 ∙ 11/2017
Flange connection following DIN EN 1092-1, form B1
1387987.02
Legend:
Mb Effective diameter of diaphragm
D Outer diameter of diaphragm seal
b Flange thickness
d₂ Bore diameter
f Height of raised face
k Pitch circle diameter
G₁ Thread
d₄ Sealing face diameter
x Number of screws
DN PN Dimensions in mm (in) x Weight in
kg (lbs)
Mb D b d2 f k d₄
15 10-40 40 (1.575) 95 (3.74) 22 (0.866) 14 (0.551) 2 (0.079) 65 (2.559) 45 (1.772) 4 1 (2.2)
20 105 (4.134) 75 (2.953) 58 (2.283) 1.3 (2.9)
25 52 (2.047) 115 (4.528) 85 (3.346) 68 (2.677) 1.5 (3.3)
Further dimensions and higher nominal pressures on request
Flange connection per ASME B 16.5, RF 125 ... 250 AA
1387987.02
Legend:
Mb Effective diameter of diaphragm
D Outer diameter of diaphragm seal
b Flange thickness
d₂ Bore diameter
f Height of raised face
k Pitch circle diameter
G₁ Thread
d₄ Sealing face diameter
x Number of screws
DN PN Dimensions in mm (in) x Weight in
Mb D b d2 f k d₄ kg (lbs)
½" 150 32 (1.26) 90 (3.543) 22 (0.866) 16 (0.63) 2 60.3 (2.374) 34.9 4 1 (2.2)
(0.079) (1.374)
300 40 (1.575) 95 (3.740) 66.7 (2.626) 4
¾" 150 100 (3.937) 69.9 (2.752) 42.9 4 1.1 (2.4)
(1.689)
300 115 (4.528) 19 (0.748) 82.6 (3.252) 4 1.6 (3.5)
1" 150 52 (2.047) 110 (4.331) 16 (0.63) 79.4 (3.126) 50.8 (2) 4 1.4 (3)
300 125 (4.921) 19 (0.748) 88.9 (3.5) 4 1.7 (3.7)
Further dimensions and higher nominal pressures on request
WIKA data sheet DS 99.26 ∙ 11/2017 Page 5 of 7
Flange connection following GOST 33259, type B
1387987.02
Legend:
Mb Effective diameter of diaphragm
D Outer diameter of diaphragm seal
b Flange thickness
d₂ Bore diameter
f Height of raised face
k Pitch circle diameter
G₁ Thread
d₄ Sealing face diameter
x Number of screws
DN PN Dimensions in mm (in) x Weight in
kg (lbs)
Mb D b d2 f k d₄
15 10-40 40 (1.575) 95 (3.74) 22 (0.866) 14 (0.551) 2 (0.079) 65 (2.559) 47 (1.85) 4 1 (2.2)
20 105 (4.134) 75 (2.953) 58 (2.283) 1.3 (2.9)
25 52 (2.047) 115 (4.528) 85 (3.346) 68 (2.677) 1.5 (3.3)
Further dimensions and higher nominal pressures on request
Flange connection per JIS
1387987.02
Legend:
Mb Effective diameter of diaphragm
D Outer diameter of diaphragm seal
b Flange thickness
d₂ Bore diameter
f Height of raised face
k Pitch circle diameter
G₁ Thread
d₄ Sealing face diameter
x Number of screws
DN PN Dimensions in mm (in) x Weight in
kg (lbs)
Mb D b d2 f k d₄
15 10 K - 20 K 40 (1.575) 95 (3.74) 21 (0.827) 15 (0.591) 1 (0.04) 70 (2.756) 51 (2.008) 4 1 (2.2)
20 100 (3.937) 75 (2.953) 56 (2.205) 1.3 (2.9)
25 52 (2.047) 125 (4.921) 19 (0.748) 90 (3.543) 67 (2.638) 1.7 (3.7)
Further dimensions and higher nominal pressures on request
Page 6 of 7 WIKA data sheet DS 99.26 ∙ 11/2017
Approvals
Logo Description Country
EAC (option) Eurasian Economic Community
Pressure equipment directive
- CRN Canada
Safety (e.g. electr. safety, overpressure, ...)
- MTSCHS (option) Kazakhstan
Permission for commissioning
Certificates (option)
■■ 2.2 test report per EN 10204 (e.g. state-of-the-art
manufacturing, material proof, indication accuracy for
diaphragm seal systems)
■■ 3.1 inspection certificate per EN 10204 (e.g. material
proof for wetted metallic parts, indication accuracy for
diaphragm seal systems)
Approvals and certificates, see website
Ordering information
Diaphragm seal:
Diaphragm seal model / Process connection (standard, flange size, nominal pressure, sealing face) / Materials (upper body,
sealing face, diaphragm, sealing) / Level of cleanliness of wetted parts / Origin of wetted parts / Design per NACE / Connection
to the measuring instrument / Certificates
Diaphragm seal system:
Diaphragm seal model / Pressure measuring instrument model (per data sheet) / Mounting (direct mounting, cooling
element, capillary) / Materials (upper body, sealing face, diaphragm) / Min. and max. process temperature / Min. and max.
ambient temperature / Vacuum service / System fill fluid / Certificates / Height difference / Level of cleanliness of wetted parts
/ Origin of wetted parts / Design per NACE / Diaphragm seal for mounting to zone 0 / Instrument mounting bracket / Process
connection (standard, flange size, nominal pressure, sealing face)
© 02/2005 WIKA Alexander Wiegand SE & Co. KG, all rights reserved.
The specifications given in this document represent the state of engineering at the time of publishing.
We reserve the right to make modifications to the specifications and materials.
WIKA data sheet DS 99.26 ∙ 11/2017 Page 7 of 7
11/2017 EN
WIKA Alexander Wiegand SE & Co. KG
Alexander-Wiegand-Straße 30
63911 Klingenberg/Germany
Tel. +49 9372 132-0
Fax +49 9372 132-406
info@wika.de
www.wika.de
