Pressure and Vacuum Sealed Feedthroughs from TC
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Series MF Pressure and Vacuum Sealed Feedthroughs for Multiple Sensors

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A single access port into an enclosure or process vessel is all that is needed to allow multiple probes, sensors, etc., to pass through an environmental or pressure boundary using a single feedthrough assembly.

Series MF feedthroughs can seal multiple elements within a single assembly including typically up to 40 x 0.040" dia., up to 12 x 0.118" dia. or up to 4 x 0.236" dia. elements. Please refer to the table for further details of feedthrough capacity and sizes of elements.

There are five body sizes having 1/8", 1/4", 1/2", 3/4" and 1" process connections in either BSPT (conical gas or DIN 2999 'R') and NPT threads.

Spectite® feedthroughs are designed for ease of assembly and installation. Elements can be adjusted, removed and replaced when not under pressure or vacuum conditions.

  • Saves time and costs by allowing multiple sensors to pass through one feedthrough fitting
  • Immersion length of each element can be easily adjusted as required
  • Five sizes of feedthrough assembly
  • Designed for carrying multiple elements 0.020" to 0.375" diameter
  • Suitable for a mixture of sizes and types of elements
  • Guide pressure range: Vacuum up to 10000 psi
  • Temperature range: -328°F to +1600°F
  • 316L Stainless steel wetted parts (see Cutaway View)
  • Choice of five sealant materials
  • Reusable fitting (dependant on sealant)
  • Reusable and replaceable internal components
  • ATEX Approved versions to Ex II 2 GD, Ex d IIC Gb / Ex e IIC Gb, Ex ta IIIC Da available, please contact us for more details
Standard Body Style ('A' Cap) Threaded Extension ('B' Cap) Weld Neck Flanges
Standard body style suitable for most applications. Allows the gland to be terminated into the process as well as to a terminal head or conduit at the opposite end to the process. Supplied without thread for permanent installation into the process by welding.
Specify as 'WELD' for the thread size in the order code.
For termination to a mating flange within the process, see Optional Flanges for details of the flanges available as standard.
Size 1 (1/8" Thread or equivalent) Size 2 (1/4" Thread or equivalent) Size 3 (1/2" Thread or equivalent)
Standard Thread Sizes Standard Thread Sizes Standard Thread Sizes
1/8" NPT, 1/8" BSPT, 1/8" BSPP 1/4" NPT, 1/4" BSPT, 1/4" BSPP 1/2" NPT, 1/2" BSPT, 1/2" BSPP
Alternative Thread Sizes Alternative Thread Sizes Alternative Thread Sizes
M8x1.0, 3/8" UNF-24 M12x1.5, 1/2" UNF-20 3/8" BSPT, 3/8" BSPP, 3/8" NPT
M10x1.0, 7/16" UNF-24 M14x1.5, 7/16", UNF-18 M16x1.5, 1/2" SAE-20, 5/8" UNF-18
    M20x1.5, 9/16" SAE-24, 3/4" UNF-16
Size 4 (3/4" Thread or equivalent) Size 5 (1" Thread or equivalent)  
Standard Thread Sizes Standard Thread Sizes
3/4" NPT, 3/4" BSPT, 3/4" BSPP  
Alternative Thread Sizes Alternative Thread Sizes
M24x2.0, 7/8" SAE-14, 1" UNF-14 1" NPT, 1" BSPT, 1" BSPP
  M33x2.0, 1+5/8" SAE-12, 1+1/8" UNF-14
Sealant Material Code Colour Example Operating Temperature Range Re-usable Material definition and properties
Neoprene N Green -40°F to +195°F Yes Synthetic rubber based on polychloroprene. The elastic properties of the polymer are enhanced by vulcanization. It is much more resistant to heat, light, oxidation, and petroleum than ordinary rubber.
Viton® V Brown -40°F to +435°F
(intermittently to 545°F)

Fluoroelastomer. Resists hydrocarbons, corrosive chemicals and petroleum. Solvent, acid and base resistant. Low permeation rate. Mechanically robust at high temperatures.

PTFE T White -328°F to +480°F Yes Polytetrafluoroethylene. FDA approved grade to Title 21-CFR 17. 1550 and is approved to US Pharmacopoeia Class VI. Has smooth, non-wetting, hydrophobic surfaces that resist biofilm buildup and the lowest coefficient of friction of any solid material. Low thermal transfer.
Graftite™ G Grey / Black -328°F to +1020°F
(to +1600°F in a reducing atmosphere)
No Graphite 98% purity. Impermeable to gases and liquids. Resistant to most media, not 'wetted' by molten metals or salts. Asbestos-free. No ageing or embrittlement. Good resistance to thermal shock. Conductive material (not electrically isolated).
Lava L Grey Stone -328°F to +1600°F No

Natural Magnesium Silicate (Soapstone, Steatite or Rock Talc). Crushes to a powder when compressed. Hygroscopic. Porous to light gases. Unsuitable for use with liquid media and in most vacuum applications.

Other sealant materials may be specified, usually for the individual special requirements of particular applications. Please contact us for assistance.
Style 'A' (Supplied as standard) Description Style 'B' (Alternative cap) Description

Standard Fitting with single thread for direct mounting into process.

Standard Fitting with a Style B threaded extension for conduit/terminal head or enclosure connection. The thread form is the same as the process thread unless otherwise specified.

If a different thread form is required, please specify after the 'B' in the order code, for example:
MF3 - 1/2" NPT - 0.250 - 8 - G - B BSPT

If a B cap is used with a weld neck fitting, then the thread form must be specified.

Style Example Part Code Maximum Compatible
Body Size
KF FLANGE KF16 Size 2 1.181" 0.200"
KF25 Size 3 1.575" 0.200"
KF40 Size 5 2.165" 0.200"
KF50 Size 5 2.953" 0.200"
CF FLANGE DN16CF Size 3 1.331" 0.299"
DN25CF Size 4 2.126" 0.469"
DN35-40CF Size 5 2.752" 0.500"
DN50CF Size 5 3.374" 0.630"
DN63CF Size 5 4.500" 0.681"
All flanges are supplied in 304L stainless steel as standard. Hygienic and Food Grade Flanges are also available - please contact us for further details.
CF Flanges are non-rotatable (fixed) type and comply with ISO3669-2017.
KF Flanges are compatible to the ISO Standard 2861 Specification.
Many other styles of flange available on request (DIN, JIS, ANSI, etc.), contact TC Inc. for details.

Body Size, Pressure Guide and available Bore Sizes for NPT Threads2

Body Size No. of
Size 1 (1/8")3 No. of
Size 2 (1/4") No. of
Size 3 (1/2") No. of
Size 4 (3/4")1 No. of
Size 5 (1")
Element Sizes (dia) The maximum guide pressure value (in psi) at 68°F (20°C)is shown for each sealant material according to element size1.
These ratings are a guide and the suitability of any of the products described herein for a particular application
is entirely at the discretion of the purchaser as being the best judge for that particular application.
inches mm
0.020 0.5 2 to 4 5800 5800 3600 3600 3600 4 to 8 4300 5800 3600 3600 3600      
0.032 0.8
0.040 1.0 7200 10000 7200 4 to 16 10000 10000 5800 3600 6500 8 to 40 7900 7900 4300 6500
0.059 1.5   2 to 6 2900 2900 4 to 12 8 to 28 3600
0.062 1.59
0.080 2.0
0.118 3.0 2 2100 2 to 4 5000 2900 5000 4 to 12 5000 8 to 24 2900 2100 1400 2100
0.125 3.2
0.177 4.5   2 4300 2100 3600 2 to 4 5000 2100 4300 4 to 8 2100 1000 1000 580
0.187 4.76   2 to 4
0.236 6.0 2 to 6
0.250 6.35
0.315 8.0   2 to 4 290
0.375 9.5
  1. The guide pressures shown for each type of sealant are at 68°F (20°C). Spectite® feedthroughs from TC Inc. have been designed to provide an efficient seal on the elements and restrain them from moving under pressure and vacuum. It is good installation practice to provide additional, mechanical restraint to the elements when differential pressure exceeds 50% of the feedthrough guide pressure value at 68°F (20°C). With an increase in temperature, a reduction in the maximum guide pressure value can be expected. These ratings are a guide and the suitability of any of the products described herein for a particular application is entirely at the discretion of the purchaser as being the best judge for that particular application.
  2. Other types of process connection are available, see Feedthrough Sizes.
  3. The element diameters shown are the common sizes routinely demanded for general industrial applications. Other sizes can be supplied between the minimum and maximum diameters shown.
Size 1 (1/8" Thread or equivalent) Size 2 (1/4" Thread or equivalent) Size 3 (1/2" Thread or equivalent)
Size 4 (3/4" Thread or equivalent) Size 5 (1" Thread or equivalent)  
Please note: the overall length will vary slightly depending on the sealant used and the tube size.

Enquiry Form - Multiple Element Feedthrough

1. Feedthrough Body Size

2. Thread Size

3. Element Diameter

3. Element Diameter

3. Element Diameter

3. Element Diameter

3. Element Diameter

3. Element Diameter

4. Number of Elements

5. Sealant Material

6. Cap Style

5a. B Cap Thread Size (other)

7. Optional Flange

8. Quantity Required

Additional Information

If you are unsure about the specification of the fitting you require, please use the box below to tell us about your application and one of our experienced engineers will call you back to help guide you through the selection process.

Otherwise, please use the drop down boxes provided and we will arrange for a quotation to be sent to you.

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