Dip Pipes & Dip Legs
Dip Pipes & Dip Legs
Request a quotation
Full technical data and dimensions
Request the datasheet
PTFE Lined Closed Dip Pipe
Closed-end lined dip pipe / thermowell, NB 1" to 6"
Lined dip pipe with a closed lower end — used as a fully lined thermowell or probe pocket reaching into the batch. NB 1" to 6", lengths to 5800 mm.
| Product type | Closed-end lined dip pipe / instrument pocket |
|---|---|
| Body / steel grade | ASTM A 106 Gr. B pipe, IS 2062 plate / ASTM A 105 flanges |
| Lining material | PTFE |
| Liner standard | ASTM D 1457 / ASTM D 4894-19 |
| Lining options | Virgin or anti-static (conductive black) PTFE to ASTM D 4894 & D 4895, PFA to ASTM D 3307, FEP to ASTM D 2116 |
| Flange standard | ASME/ANSI B16.5 |
| Flange class | Class 150 standard; Class 300 on request |
| Size range | NB 1" to NB 6" on NB 1.5" to 24" nozzles |
Product overview
What it does, and where it fits.
A closed dip pipe is sealed at the bottom, so it forms a dry pocket reaching into the batch rather than a flow path. That makes it the housing for a temperature probe, a pH electrode or a level sensor that must read deep inside an aggressive batch without being wetted by it.
Because the pocket is closed, the instrument can be withdrawn and replaced while the vessel is in service. The pocket itself is lined with PTFE to ASTM D 1457 over an ASTM A 106 Gr. B body, in the same size range and lengths as the straight dip pipe.
A pH probe adapter and a thermowell with a tantalum plug are available on request, the latter for duties where even PTFE permeation would give a slow instrument response.
Features
Built into every unit.
- Closed lower end forms a dry, fully lined instrument pocket
- Instrument can be changed without opening the vessel
- PTFE liner to ASTM D 1457 over ASTM A 106 Gr. B body
- NB 1" to 6" on NB 1.5" to 24" nozzles, lengths to 5800 mm
- pH probe adapter and tantalum-plug thermowell on request
Benefits
Why it earns its place in the line.
- Keeps sensitive instruments out of contact with an aggressive batch
- Instrument replacement without vessel entry or shutdown
- Outstanding corrosion resistance to aggressive organic and inorganic chemicals across a wide temperature range
- Non-stick, non-wetting bore — low surface energy keeps product moving and simplifies cleaning
- Chemically inert and pure; no additives, plasticisers, stabilisers or lubricants to contaminate the process fluid
- The lowest coefficient of friction of any solid, reducing pressure drop and deposit build-up
Applications & industries
Where it is specified.
Typical applications
- Temperature measurement inside lined and glass-lined reactors
- pH and conductivity probe housings
- Level and interface probe pockets
- Any deep instrument reading in corrosive service
Industries served
- Chemical processing
- Pharmaceutical
- Petrochemical
- Oil & gas
- Power generation
- Pulp & paper
- Mining & metallurgy
- Agrochemicals & dyes
Technical data
Specification for PTFE Lined Closed Dip Pipe.
Figures below are for this product only — every item in the range carries its own dimension table.
| Product type | Closed-end lined dip pipe / instrument pocket |
|---|---|
| Body / steel grade | ASTM A 106 Gr. B pipe, IS 2062 plate / ASTM A 105 flanges |
| Lining material | PTFE |
| Liner standard | ASTM D 1457 / ASTM D 4894-19 |
| Lining options | Virgin or anti-static (conductive black) PTFE to ASTM D 4894 & D 4895, PFA to ASTM D 3307, FEP to ASTM D 2116 |
| Flange standard | ASME/ANSI B16.5 |
| Flange class | Class 150 standard; Class 300 on request |
| Size range | NB 1" to NB 6" on NB 1.5" to 24" nozzles |
| Temperature range | Continuous service to 260 °C (PTFE melting point 327 °C, PFA 306 °C, FEP 260 °C) |
| Pressure rating | ASME/ANSI B16.5 Class 150 flanges as standard; Class 300 available on request |
| Manufacturing standard | ASTM F 1545 |
| Spark testing | Every lined component spark tested at 5000 × E volts (E = liner thickness in mm), to a maximum of 15 000 V |
| Hydro testing | Hydrostatic or pneumatic test according to the lining technique; hydrostatic test on components with vent holes |
| Inspection | Dimensional and visual examination of liner and steel parts — weld aspect, overall dimensions, collar size, liner thickness, surface flaws and paint thickness |
| Vent holes | 3 mm diameter vent holes — one per fitting; spools under 500 mm get a single central hole, spools over 500 mm get two holes about 150 mm from each end |
| External protection | Zinc epoxy primer, minimum 60 μm dry film, over steel sand-blasted to SA 2.5 |
| Certification | EN 10204 3.1 mill certificates and FDA certification for the fluoropolymer available on request |
| Standard version | Straight dip pipe, closed end |
| Face to face | 150 mm |
| NB₁ | NB₂ | Face to face X (±2) | Length min (±2) | Length max (±2) | PTFE |
|---|---|---|---|---|---|
| 1" | 1.5"–24" | 150 | 150 | 5800 | ✓ |
| 1.5" | 2"–24" | 150 | 150 | 5800 | ✓ |
| 2" | 3"–24" | 150 | 150 | 5800 | ✓ |
| 2.5" | 3"–24" | 150 | 200 | 5700 | ✓ |
| 3" | 4"–24" | 150 | 200 | 5700 | ✓ |
| 4" | 6"–24" | 150 | 200 | 5700 | ✓ |
| 6" | 8"–24" | 150 | 300 | 3000 | ✓ |
All dimensions in mm. Dimensions match the straight dip pipe; the difference is the closed lower end.
Available on request
- Angular spool option for tilting up to 20°
- pH probe adapter
- Thermowell with tantalum plug
FAQ
Questions we are asked about this item.
PTFE is a good barrier but not a perfect one, and its thickness slows heat transfer. A tantalum plug at the tip gives a fast, accurate temperature reading while staying resistant to most aggressive media.
Yes. The pocket is closed to the process, so the instrument sits in a dry bore and can be withdrawn without breaking containment.
Related products
Commonly specified alongside PTFE Lined Closed Dip Pipe.
Dip Pipes & Dip Legs
Lined Fittings
Dip Pipes & Dip Legs
Enquiry
Tell us your line size — we'll confirm the spec.
Send the bore, the media, the temperature and pressure, and the flange standard you work to. Drawings and custom sizes welcome.
Not sure which spec fits your process?
Send your requirement — media, temperature, pressure, dimensions — and we'll recommend the right product or fabricate it.
Talk to an engineer