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Rings and stoppers are useful aids in the daily lab routine. Manufacturers like Bohlender, Deutsch&Neumann, Bürkle and Duran produce stoppers and rings for various types of vessels, flasks and valves. Stoppers are made of fluoroplastics (e.g. PTFE), silicone or glass. Further stoppers are available in numerous shapes with variable top and bottom diameter, with a middle hole or a lamella-like grinding.  

Here you find further information on fluoroplastics.

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Rings & Stoppers

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  1. Duran Group

    Guko/EPDM, 29x16x9mm 10 pc/PAK

    €29.50
    SKU: DU292021709
    In Stock
  2. Duran Group

    Guko/EPDM, 36x22x15 mm 10 pc/PAK

    €36.50
    SKU: DU292022302
    In Stock
  3. Duran Group

    Guko/EPDM, 44x27x19mm 10 pc/PAK

    €41.40
    SKU: DU292022705
    In Stock
  4. Duran Group

    Guko/EPDM, 53x33x24mm 10 pc/PAK

    €50.10
    SKU: DU292023204
    In Stock
  5. Duran Group

    Guko/EPDM, 63x43x33mm 10 pc/PAK

    €52.90
    SKU: DU292023607
    In Stock
  6. Duran Group

    Plastic tubing connector/PP, curved, 8x4mm, 10 pc/PAK

    €12.90
    SKU: DU292470504
    In Stock
  7. Hirschmann

    Steril Stopper BIO-SILICO, orange, N32, 10 pc/PAK

    €115.00
    SKU: HI8905932
  8. Duran Group

    Pouring ring, 5 pc/PAK

    €13.70
    SKU: DU1088678
    In Stock
  9. Duran Group

    Pouring ring/PP, green, 10 pc/PAK

    €4.90
    SKU: DU1089911
    In Stock
  10. Duran Group

    Pouring ring/PP, gray, 10 pc/PAK

    €4.90
    SKU: DU1089914
    In Stock
  11. Duran Group

    Pouring ring/PP, yellow, 10 pc/PAK

    €4.90
    SKU: DU1089917
    In Stock
  12. Duran Group

    Pouring ring GLS 80, 10 pc/PAK

    €16.40
    SKU: DU1160166
    In Stock
  13. Duran Group

    Pouring ring/PP, blue for DIN-thread GL 32, 10 pc/PAK

    €4.30
    SKU: DU292421907
    In Stock
  14. Duran Group

    Pouring ring/PP, blue for DIN-thread GL 45, 10 pc/PAK

    €5.00
    SKU: DU292422809
    In Stock
  15. Duran Group

    Pouring ring/ETFE, red for DIN-thread GL 45, 10 pc/PAK

    €12.90
    SKU: DU292442802
    In Stock
  16. Duran Group

    Seal PTFE-coated, GL 14 for red screw caps, 10 pc/PAK

    €4.70
    SKU: DU292480805
    In Stock
  17. Duran Group

    Seal PTFE-coated, GL 18 for red screw caps, 10 pc/PAK

    €7.00
    SKU: DU292481107
    In Stock
  18. Duran Group

    Seal PTFE-coated, GL 32 for red screw caps, 10 pc/PAK

    €16.20
    SKU: DU292481904
    In Stock
  19. Duran Group

    Seal PTFE-coated, GL 45 for red screw caps, 10 pc/PAK

    €27.90
    SKU: DU292482806
    In Stock
  20. IDL GmbH

    Gray stopper made of butyl rubber 100 pcs.

    €16.32
    SKU: ID1200420220
    In Stock
  21. IDL GmbH

    Cork stopper, H x diam. top/bottommm 16x7x4 100 pcs.

    €17.90
    SKU: ID2400111020
    In Stock
  22. IDL GmbH

    Cork stopper, H x diam. top/bottommm 16x8x5 100 pcs.

    €17.90
    SKU: ID2400111030
    In Stock
  23. IDL GmbH

    Cork stopper H x diam. top/bottommm 18x10x7 100 pcs.

    €13.80
    SKU: ID2400111050
    In Stock
  24. IDL GmbH

    Cork stopper H x diam. top/bottommm 20x11x8 100 pcs.

    €14.06
    SKU: ID2400111060
    In Stock
  25. IDL GmbH

    Cork stopper, H x diam. top/bottom mm 22x16x13 100 pcs.

    €14.83
    SKU: ID2400111110
    In Stock
  26. IDL GmbH

    Cork stopper, H x diam. top/bottom mm 22x18x15 100 pcs.

    €16.87
    SKU: ID2400111130
    In Stock
  27. IDL GmbH

    Cork stopper, H x diam. top/bottom mm 23x19x16 100 pcs.

    €17.90
    SKU: ID2400111140
    In Stock
  28. IDL GmbH

    Cork stopper, H x diam. top/bottom mm 26x20x17 100 pcs.

    €21.47
    SKU: ID2400111150
    In Stock
  29. IDL GmbH

    Cork stopper, H x diam. top/bottom mm 26x22x18 100 pcs.

    €28.63
    SKU: ID2400111170
    In Stock
  30. IDL GmbH

    Cork stopper, H.XO./XU.D./MM 32X21X17 conical, 100 pcs.

    €22.62
    SKU: ID2400111190
    In Stock
  31. IDL GmbH

    Cork stopper, H.XO./XU.D./MM 27X24X20 conical, 100 pcs.

    €40.94
    SKU: ID2400111220
    In Stock
  32. IDL GmbH

    Cork stopper, H.XO./XU.D./MM 27X28X24 conical, 100 pcs.

    €48.67
    SKU: ID2400111240
    In Stock
  33. IDL GmbH

    Cork stopper, H.XO./XU.D./MM 27X30X26 conical, 100 pcs.

    €61.57
    SKU: ID2400111250
    In Stock
  34. IDL GmbH

    Cork stopper, H.XO./XU.D./MM 27X36X32 conical, 100 pcs.

    €80.34
    SKU: ID2400111280
    In Stock
  35. IDL GmbH

    Cork ring diam. outer/inner 80x30mm, 100 pcs.

    €205.00
    SKU: ID2400200800
    In Stock
  36. IDL GmbH

    Cork ring diam. outer/inner 110x60mm, 100 pcs.

    €286.00
    SKU: ID2400201100
    In Stock
  37. IDL GmbH

    Cork ring diam. outer/inner 140x90mm, 100 pcs.

    €409.00
    SKU: ID2400201400
    In Stock
  38. IDL GmbH

    Cork ring diam. outer/inner 170x120mm, 100 pcs.

    €532.00
    SKU: ID2400201700
    In Stock
  39. IDL GmbH

    Cork ring 210 X 150 X 30 MM

    €10.43
    SKU: ID2400202100
    In Stock
  40. IDL GmbH

    Cork ring 240 X 180 X 30 MM

    €13.50
    SKU: ID2400202400
    In Stock
  41. IDL GmbH

    Polystopper/PE, NS 10/19, 100pc/PAK

    €100.00
    SKU: ID2400391100
    In Stock
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Fluoroplastics: Rings & Stoppers made of PTFE, FEP, PFA etc.

Fluoroplastics belong to the family of thermoplastics. The higher the fluoric content, the better the chemical and thermal capacity of fluoropolymers. A number of characteristics makes fluoroplastics an ideal material for rings and stoppers. Unique properties are:

• universal chemical resistance,
• high thermal load capacity (-200 °C up to +260 °C),
• resistance to all sterilisation temperatures,
• resistance to environmental changes (weather, light),
• ultra-low friction coefficient and
• UV-resistance.

Further, accessories made of fluoroplastics are
• non-flammable,
• non-adhesive,
• unbreakable,
• physiologically safe and
• inert, without taste or odour.

In particular, the chemical and thermal resistance of PTFE is remarkable (-260°C up to +300°). The permanent temperature resistance depends on the load, so PTFE can be used from -200°C to +260°C at moderate mechanical load. PTFE lab equipment, e.g. hoses, magnetic stirring bars, bottles, or stirrer shafts, has a white appearance, a non-adhesive surface and extraordinary slip characteristics.

The chemical and mechanical properties of FEP are similar to those of PTFE. However, the upper limit of the permanent working temperature is lower (+205° C). FEP lab supply, e.g. hoses, is translucent to transparent and non-porous.

PFA has similar chemical and thermal characteristics to PTFE. PFA labware, e.g. hoses, bottles, or round-bottom flasks, is translucent to transparent, non-porous and particularly useful in high-purity work.

PP however does not belong to the family of fluoroplastics. PP is autoclavable (at +121° C) and has good mechanical and chemical properties almost up to its softening point. Lab supply made of PP, e.g. olives for stopcocks and valves or also lab furniture, is unbreakable and an economical alternative.

Cleaning of Fluoroplastics

Due to their smooth, non-wetting surface, all fluoroplastics (PTFE, PFA and FEP) can easily be cleaned. However, abrasive scouring agents might damage the surface and result in a milkiness of the vessels. All neutral detergents (pH 7) are suitable, for a stronger contamination an alkaline detergent up to pH 12 is recommended. Vessels should only be cleaned or dryed in laboratory washing machines when they are completely opened. Here you find a selection of cleaners and disinfectants as well as further information. Vessels made of PTFE, PFA or FEP can be autoclaved or sterilised at +121° C. To avoid deformation or destruction, all vessels with screw covers or stoppers have to be open while being autoclaved. Pressurisation (from inside) should be avoided, too due to the thin walls of standard PTFE, PFA or FEP bottles.

Duran Stoppers made of Borosilicate Glass

Stoppers made of borosilicate glass by Duran are an alternative to stoppers made of fluoroplastics. Borosilicate glass 3.3 is resistant to water, neutral and acid solutions, concentrated acids and acid mixtures, chlorine, bromine, iodine and organic substances. Further, borosilicate glass endures temperatures over 100° C and is universally applicable. Hence Duran glass is suitable ideally for the application in laboratories. Only HF-alkylation, concentrated phosphoric acid and strong alkali in combination with high temperatures (>100°C) lead to glass corrosion. For any other application areas e.g. Duran semi-hollow glass flat-head stoppers are available at Analytics-Shop.com.

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