Brand: WIKA

WIKA TW45 Threaded Protection Tube, DIN 43772 Form 5 and 8

Name: WIKA TW45 Threaded Protection Tube
Brand: WIKA
SKU: TW45

Description

WIKA TW45 threaded protection tube to DIN 43772 forms 5 and 8

The WIKA TW45 is a threaded protection tube made from stainless steel 1.4571 for low and medium process loads. It is designed after DIN 43772 and is used in the chemical industry, process technology and equipment manufacturing. A protection tube differs from a bar-stock thermowell in how it is made: the TW45 is built from a tube closed at the tip by a welded solid end, which makes it lighter and quicker to respond, but less suited to heavy flow loads than the TW20 or TW25. Seven Star LLC supplies the TW45 in Oman and the GCC as an independent supplier in Muscat.

Decoding the TW45 forms

Two designs are listed. TW45-F is form 5 per DIN 43772: a process thread G ½ B or G ¾ B male, and a female thread for the thermometer (G ½ or G ¾). TW45-G is form 8: the same process thread, but the connection to the thermometer is itself a G ½ B or G ¾ B male thread, which suits machine glass thermometers and certain dial thermometers. The version is either per DIN 43772 or a design similar to DIN 43772 with a thinner wall for fast response.

Technical specifications of the TW45

Parameter	Specification
Manufacturer / part number	WIKA / TW45
Type	Threaded protection tube
Forms	TW45-F form 5; TW45-G form 8
Version	Per DIN 43772, or similar to DIN 43772 (fast response)
Wetted material	Stainless steel 1.4571
Process connection	G ½ B or G ¾ B male thread
Connection to thermometer, TW45-F	G ½ or G ¾ female thread
Connection to thermometer, TW45-G	G ½ B or G ¾ B male thread
Bore, per DIN 43772	7, 9 or 11 mm
Bore, similar to DIN 43772	6.2, 8.2, 8.5 or 10.2 mm
Insertion length U, TW45-F	82, 142, 182, 232 or 382 mm
Insertion length U, TW45-G	73, 110, 170, 260 or 410 mm
Overall length L	Insertion length U1 + 28 mm
Certificates (option)	2.2 test report; 3.1 inspection certificate

Dimensional examples from the data sheet

The dimension table covers every bore, thread and wall combination. Some examples for TW45-F in stainless steel 1.4571 illustrate how wall thickness changes with the bore.

Process thread	Bore Ø d1	Outer Ø F1	Wall S	Weight, U1 = 82 mm	Weight, U1 = 382 mm
G ½ B	7 mm	12 mm	2.5 mm	0.15 kg	0.33 kg
G ½ B	11 mm	14 mm	1.5 mm	0.12 kg	0.28 kg
G ½ B	6.2 mm	8 mm	0.9 mm	0.12 kg	0.18 kg
G ¾ B	9 mm	14 mm	2.5 mm	0.24 kg	0.45 kg
G ¾ B	10.2 mm	12 mm	0.9 mm	0.21 kg	0.28 kg

The sealing collar is 26 mm in diameter on G ½ B and 32 mm on G ¾ B, with spanner widths of 27 and 32 mm respectively. A copper-alloy variant with an 8.5 mm bore also appears in the table for the fast-response design.

Working principle and limits of the TW45

The protection tube isolates the thermometer from the medium, so the thermometer can be exchanged while the line is in operation and is shielded from pressure and flow. The permitted process temperature and pressure are not stated as one value: they depend on the DIN 43772 load diagram, the tube dimensions and material, and the flow rate and density of the medium. A thin-walled fast-response tube will tolerate less load than a thick-walled one, so the version must be matched to the duty. An optional wake frequency calculation per Dittrich/Klotter is provided as an engineered service by the manufacturer and is subject to charges.

Matching thermometers to the TW45

Stem lengths follow formulas in the data sheet. For TW45-F with a dial thermometer on connection designs S, 4, 4.1, 5, 6.1, 6.2, 6.3 and 7, l1 = L − 10 mm for a parallel thread, or l1 = U1 + 18 mm; with a tapered thread, l1 = L − 2 mm. For TW45-G with connection design 3, l1 = L − 12 mm. Machine glass thermometers use similar rules with connection designs E and 3. These relationships make it straightforward to specify a thermometer stem to suit the chosen tube.

Related models: TW15, TW20 and TW61

If the process load is higher than a tube can handle, the threaded bar-stock TW15 or the weld-in TW20 and TW25 are the next step. If the process is sanitary, the TW61 orbital-weld tube is intended for that duty. The TW45 remains the economical, standard-pattern choice for general utility and chemical lines.

Selection and ordering checklist for the TW45

Form: TW45-F (form 5) or TW45-G (form 8).
Version: per DIN 43772 or fast-response design.
Process thread G ½ B or G ¾ B and the thermometer thread.
Bore size and the thermometer sheath that must fit it.
Insertion length U from the standard list.
Certificate level 2.2 or 3.1.
Process data to confirm the load class.

Installation and maintenance of the TW45

Use a suitable gasket on the sealing collar, tighten with the correct spanner width, and avoid over-torquing a thin-walled tube. Inspect the tube at shutdowns for corrosion, and handle thin-walled fast-response designs carefully because their wall is under 1 mm in some sizes.

Typical applications in Oman and the GCC

Utility water, chemical dosing, HVAC plant, process skids and general processing lines in the region are typical uses, particularly where the process loads are moderate and installation by a simple thread is preferred.

Information to send with an RFQ for the TW45

Form, version and process thread.
Bore and insertion length.
Thermometer model and thread to fit.
Medium, temperature, pressure and flow.
Certificates, quantity and delivery location.

Documents and quotation

The WIKA data sheet TW 95.45 for the TW45 is attached on this page. Send the details above and Seven Star LLC will quote as an independent supplier, with no claim to an official WIKA status.

Datasheets & Documents

Datasheet WIKA TW45 Threaded Protection Tube, DIN 43772 Form 5 and 8 Datasheet Download

Reviews (0)

Reviews

There are no reviews yet.

How would you rate this product?

About brand

WIKA is the German manufacturer of pressure, temperature, level and flow instruments, best known for its pressure gauges. Alexander Wiegand and Philipp Kachel founded it on 2 January 1946 in Klingenberg am Main, Bavaria. The name comes from the first two letters of their surnames. WIKA is still run by the Wiegand family and is headquartered in Klingenberg.

Seven Star LLC is an independent supplier in Muscat. We list WIKA pressure gauges, diaphragm seals, transmitters, switches, thermometers and thermowells, and supply them to plants, contractors and panel builders in Oman and the GCC by model and order code.

WIKA company profile

Established	2 January 1946, Klingenberg am Main, Germany, by Alexander Wiegand and Philipp Kachel
First products	Mechanical pressure and temperature gauges
Ownership	Family-owned; managed by Alexander Wiegand, grandson of the founder, since 1996
Product families	Pressure gauges, diaphragm seals, pressure transmitters and switches, thermometers, RTDs, thermocouples, thermowells, calibration equipment, level and flow instruments

Milestones

1946: Alexander Wiegand and Philipp Kachel found the company in Klingenberg am Main on 2 January; pressure gauge production starts at the end of the year. The name WIKA comes from the first letters of their surnames.
1951: Konrad Wiegand, the founder's son, takes over management.
1967: Ursula Wiegand leads the company after her husband's death.
1986: The company is reunited with the Kachel thermometer factory, which Philipp Kachel had set up after leaving in 1956.
1994: Certification to DIN ISO 9001.
1996: Alexander Wiegand, the founder's grandson, becomes head of the company.

WIKA products we list

Family	Models	Typical use
Bourdon tube pressure gauges	111.10, 111.12, 212.20, 213.53, 232.50, 233.50, 232.30/233.30 safety pattern	HVAC and utilities (111 series) to process plants (23x series in stainless steel)
Diaphragm and differential pressure gauges	432.50, 732.51, 700.01, DPGT43	Low pressures, viscous or dirty media, and filter differential pressure
Diaphragm seals	990.10, 990.27	Separating the gauge from corrosive, hot or clogging media
Transmitters, switches and test gauges	A-10, UPT-20, PSM01, CPG1500	4-20 mA pressure signals, switching, and precision calibration checks
Thermometers	TG54, Model 55, A52, 73 gas-actuated	Local temperature indication on pipes, vessels and HVAC
Temperature sensors and thermowells	TR10, TR12-B, TR33, TC10-B, TW10 flanged, TW15 threaded	RTD and thermocouple measurement in process lines

The WIKA model number tells you the build. In 232.50, the first digit 2 means stainless steel wetted parts, the second digit 3 means a liquid-fillable case, and ".50" is the case style. The 111 series uses copper alloy wetted parts and suits water and air. Where the medium is corrosive, very hot or would block the gauge, a diaphragm seal such as the 990.27 keeps it away from the Bourdon tube. For temperature, a thermowell like the TW10 lets you remove the sensor without opening the process.

Where WIKA instruments are used

In Oman and the GCC, WIKA gauges, transmitters and thermometers are used in oil and gas, refining and petrochemical plants, power and desalination, water networks, district cooling and HVAC, and on skids and machines from OEMs.

Ordering WIKA instruments: what we need

Send the model, dial size (for example 63, 100 or 160 mm), range and unit, connection size and position (lower or back mount), accuracy class and whether liquid filling is needed. For diaphragm seals and thermowells, add the process connection, materials and insertion length.

Facts checked against WIKA company history, October 2026.

Browse WIKA products by category: Pressure Instrumentation, Temperature Instrumentation.

FAQ

Questions about the WIKA TW45 Threaded Protection Tube, DIN 43772 Form

Answers from our engineering team on installation, compatibility and integration.

01What is the difference between TW45-F and TW45-G?

TW45-F is DIN 43772 form 5 with a female thread for the thermometer, while TW45-G is form 8 with a male G 1/2 B or G 3/4 B thread to the thermometer.

02Which material is used for the TW45?

The wetted material is stainless steel 1.4571. A copper-alloy fast-response variant is shown in the dimension table.

03What bore sizes are available for the TW45?

Per DIN 43772 the bore is 7, 9 or 11 mm. The design similar to DIN 43772 for fast response has 6.2, 8.2, 8.5 or 10.2 mm bores.

04Which insertion lengths are listed for the TW45?

TW45-F lists 82, 142, 182, 232 and 382 mm; TW45-G lists 73, 110, 170, 260 and 410 mm. Overall length is U1 plus 28 mm.

05How is the permitted pressure of the TW45 determined?

It depends on the DIN 43772 load diagram, the dimensions and material, and the flow rate and medium density. A wake frequency calculation can be ordered as an engineered service.