Pressure

Diaphragm seal with flange connection

With flush diaphragm
Model 990.27
WIKA data sheet DS 99.27

Applications

■ Aggressive, highly viscous, crystallising or hot media

■ Process industry
■ Machine building and automation

Special features

■ Flange with flush welded diaphragm Diaphragm seal with flange connection, model 990.27
■ Common standards and nominal widths available
■ Wide variety of different materials and material
combinations

Description

Diaphragm seals are used to protect pressure measuring The model 990.27 diaphragm seal with flush flange
instruments in demanding applications under difficult condi- connection is assembled from the upper body of a diaphragm
tions. These diaphragm seal systems, consisting of a process seal and the wetted parts (sealing face and diaphragm).
transmitter, pressure sensor, pressure gauge or pressure This diaphragm seal model is optimised for applications in
the chemical, petrochemical and the oil and gas industries
switch with diaphragm seal, can be combined individually for
and is therefore available in a wide range of dimensions in
each customer application. For this, a wide range of different
accordance with the standards common in these markets.
designs, process connections, mounting types and wetted
materials are available. Through the high number of possible combinations and
aided by the individual checking of the operating conditions,
Diaphragm seal models with flange connections are avail- it is ensured that the ideal customer solution for a diaphragm
able with flush or internal diaphragms, in tubular design or seal system can be found with the model 990.27.
as in-line diaphragm seals. The variants mentioned are also
available in a cell-type design.

WIKA data sheet DS 99.27 ∙ 07/2024 Page 1 of 14

Data sheets showing similar products:

Flange connection, with internal diaphragm; model 990.26; see data sheet DS 99.26
Diaphragm seal system with pressure gauge per EN 837-1; model DSS27M;
see data sheet DS 95.12
Diaphragm seal system with high-quality pressure sensor; model DSS27T;
see data sheet DS 95.13
Installation example
Model 990.27 with directly mounted pressure gauge

Diaphragm seal system Mounting situation 1)

Seal
2) Process connec-
tion on the customer side

Pressure gauge

Direct mounting

Upper body of diaphragm

seal d4
k
Diaphragm D

Raised face
Legend:
D Outer diameter of diaphragm seal
b

d4 Raised face diameter

f

k Pitch circle diameter

b Flange thickness
f Height of raised face

14219130.01
1) Illustration example of the mounting situation. The operator is responsible
for ensuring that the installation complies with the standards.
2) Not included in delivery

Diaphragm seal system

Diaphragm seal systems are mounted to existing connections, which are welded to a pipeline, a process reactor or a tank.
A diaphragm made of the appropriate material separates the medium from the measuring instrument. The internal space
between the diaphragm and the measuring instrument is completely filled with a system fill fluid.

Measuring element
The pressure of the medium is transferred via the elastic diaphragm to the system fill fluid and then on to the measuring instru-
ment. A diaphragm seal and its components are perfectly matched to each other to ensure a reliable measurement.

Mounting type
Mounting of the diaphragm seal to the measuring instruments may be made via direct mounting, for high temperatures via a
cooling element or via a flexible capillary.

Direct mounting via axial Capillary (example) Heat sink (examples)

connection adapter

WIKA data sheet DS 99.27 ∙ 07/2024 Page 2 of 14

Technical information
Data sheet number Title
IN 00.06 Diaphragm seals and diaphragm seal systems, application – functionality – design
IN 00.25 Diaphragm seal systems for vacuum processes
IN 00.21 General information about NACE standards for sour gas applications
IN 00.41 Specifications of oil- and grease-free instruments

→ See download on the WIKA website

Specifications
Basic information for diaphragm seal systems
Version Diaphragm seal with flange connection
Other versions ■ Per NACE 1) MR0175 / ISO 15156, use in H2S-containing environments in oil and gas
production
■ Per NACE 1) MR0103 / ISO 17945, metals resistant to hydrogen sulphide stress crack-
ing
■ With pre-volume deflagration flame arrester 2) for mounting to zone 0 (EPL Ga); model
910.21; see data sheet AC 91.02
Pressure range The maximum permissible operating pressure must be determined individually for each
diaphragm seal system. It is dependent on the operating temperature, the process connec-
tion, the joining method, the system fill fluid and the mounted measuring instrument.
Connection to the instrument ■ Axial connection adapter for weld seam
■ Suitable connection adapter to the instrument (e.g. G ½, G ¼, ½ NPT or ¼ NPT)

Mounting type 3) ■ Direct mounting

■ Capillary
■ Heat sink

Vacuum service 4) ■ Basic service

■ Advanced service
■ Premium service

1) General information about NACE standards; see technical information IN 00.21

2) Only for instruments with Ex approval
3) For possible mounting type, see page 2
4) Diaphragm seal systems for vacuum processes; see technical information IN 00.25

Process connection
Standard 1) ■ DIN EN 1092-1
■ ASME B16.5-2017
■ GOST 33259
■ API 6A
■ JIS B2220
Size
DIN EN 1092-1 ■ DN 25 ■ DN 40 ■ DN 50 ■ DN 65
■ DN 80 ■ DN 100 ■ DN 125

ASME B16.5-2017 ■ 1" ■ 1 ½" ■ 2" ■ 2 ½"

■ 3" ■ 4" ■ 5"

GOST 33259 ■ DN 25 ■ DN 40 ■ DN 50 ■ DN 65
■ DN 80 ■ DN 100 ■ DN 125

API 6A ■ 1 1/8" ■ 1 1/16" ■ 1 13/16" ■ 2 1/16"

JIS B2220 ■ DN 25A ■ DN 40A ■ DN 50A ■ DN 80A

■ DN 100A

WIKA data sheet DS 99.27 ∙ 07/2024 Page 3 of 14

 Flange material DN PN Maximum allowable pressure in MPa [psi] at ambient
temperature 21 °C [60.8 °F]
Titanium grade 7 (3.7235) 25A, 50A, 80A, 5K 0.6 [87]
100A
10K 1.2 [175]
16K 2.3 [337]
20K 2.9 [425]
30K 4.3 [637]
40K 5.8 [850]
63K 9.2 [1,338]

Accessories and spare parts

Model Description Order number

910.27 Flushing ring for flange-connection diaphragm seals On request
→ See data sheet AC 09.05

IBF2, IBF3 Monoblock with flange connection On request

→ See data sheet AC 09.25

910.16 Instrument mounting bracket form H per DIN 16281, 100 mm, aluminium, 9091858
black
Instrument mounting bracket form H per DIN 16281, 100 mm, 9091882
stainless steel
→ See data sheet AC 09.05 On request

Ordering information
Diaphragm seal:
Diaphragm seal model / Process connection (standard, flange size, nominal pressure, sealing face) / Material combination
(upper body of diaphragm seal, wetted parts) / Level of cleanliness of wetted parts / Origin of wetted parts / Design per NACE /
Connection to the measuring instrument / Certificates / Flushing ring

Diaphragm seal system:

Diaphragm seal model / Pressure measuring instrument model (per data sheet) / Mounting (direct mounting, cooling
element, capillary) / Material combination (upper body of diaphragm seal, wetted parts) / 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) / Flushing ring
© 11/2002 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.
In case of a different interpretation of the translated and the English data sheet, the English wording shall prevail.
07/2024 EN

WIKA data sheet DS 99.27 ∙ 07/2024 Page 14 of 14

WIKA Alexander Wiegand SE & Co. KG

Alexander-Wiegand-Straße 30
63911 Klingenberg/Germany
Tel. +49 9372 132-0
info@wika.de
www.wika.de