Menu
Menu
Filtrar productos
Productos disponibles
→
Family
Dimension
Material
Hardness
Tech. Inf.
Stock
Expected Stock
Price
Buy
SPIRAL BUR 95,25X101,40X2,05 WHITE PTFE (BS240) (FDA-Compliant)
Part number: BUR240PTFEXWH
Weight : 2.8000 gr.
Customs tariff code: 39269097
Country of origin: GB
SPIRAL BUR 95,25x104,77X2,55 WHITE FDA PTFE (BS343-R46)
Part number: BUR343PT17301
Weight : 5.4500 gr.
Customs tariff code: 39269097
Country of origin: CN
Approvals:
HOMOL-1935/2004
HOMOL-FDA
Quality :
SPIRAL BUR 98,43X104,77X2,05 WHITE PTFE (BS241) (FDA-Compliant))
Part number: BUR241PTFESWH
Weight : 2.9000 gr.
Customs tariff code: 39269097
Country of origin: GB
SPIRAL BUR 101,60X111,11X2,55 WHITE FDA PTFE (BS345-R48)
Part number: BUR345PT17301
Weight : 12.5400 gr.
Customs tariff code: 39269097
Country of origin: CN
Approvals:
HOMOL-1935/2004
HOMOL-FDA
Quality :
SPIRAL BUR 104,78X114,30X2,55 WHITE FDA PTFE (BS346-R49)
Part number: BUR346PT17301
Weight : 6.0100 gr.
Customs tariff code: 39269097
Country of origin: CN
Approvals:
HOMOL-1935/2004
HOMOL-FDA
Quality :
SPIRAL BUR 111,13X120,65X2,55 WHITE FDA PTFE (BS348-R51)
Part number: BUR348PT17301
Weight : 0.0060 gr.
Customs tariff code: 39269097
Country of origin: CN
Approvals:
HOMOL-1935/2004
HOMOL-FDA
Quality :
SPIRAL BUR 114,30X127,00X3,73 WHITE FDA PTFE (BS425-R53)
Part number: BUR425PT17301
Weight : 0.0120 gr.
Customs tariff code: 39269097
Country of origin: CN
Approvals:
HOMOL-1935/2004
HOMOL-FDA
Quality :
SPIRAL BUR 117,48X123,82X2,05 WHITE FDA PTFE (BS247)
Part number: BUR247PT17301
Weight : 0.0030 gr.
Customs tariff code: 39269097
Country of origin: CN
Approvals:
HOMOL-1935/2004
HOMOL-FDA
Quality :
SPIRAL BUR 117,48X130,17X3,73 WHITE FDA PTFE (BS426-R54)
Part number: BUR426PT17301
Weight : 0.0130 gr.
Customs tariff code: 39269097
Country of origin: CN
Approvals:
HOMOL-1935/2004
HOMOL-FDA
Quality :
SPIRAL BUR 177,80X190,50X3,73 WHITE PTFE (BS441) (FDA-Compliant)
Part number: BUR441PTFESWH
Weight : 19.4000 gr.
Customs tariff code: 39269097
Country of origin: GB
SPIRAL BUR 120,65X127,00X2,05 WHITE PTFE (BS248) (FDA-Compliant)
Part number: BUR248PTFEXWH
Weight : 3.5000 gr.
Customs tariff code: 39269097
Country of origin: GB
SPIRAL BUR 120,65X133,35X3,73 WHITE FDA PTFE (BS427-R55)
Part number: BUR427PT17301
Weight : 0.0130 gr.
Customs tariff code: 39269097
Country of origin: CN
Approvals:
HOMOL-1935/2004
HOMOL-FDA
Quality :
technical data
| Back-Up Rings | Profile | Material | Hardness | Temperature |
| BUR |  | NBR | 90 SH A | -20 to +100/+120 ºC |
| SPIRAL BUR |  | PTFE VIRGEN | -150 to +260 ºC |
QUICK LINKS
Rings that improve O-Rings performance
Back-up Rings are parts fitted together with an O-Ring. They do not properly have a sealing function but are rather dedicated to improving the performance of said O-Ring. Depending on the application and the housing, one or two BUR can be fitted around the OR allowing its use in static or dynamic systems, in reciprocating or rotating movements and achieving the use of a wide range of OR hardnesses.
Its profile is pretty basic since its most simple version is a rectangular section washer. However, the most standard profile is the concave cross-section washer that allows the O-Ring to be seated, improving the anti-extrusion effect.
The standard material that we usually stock is NBR90 although it can also be manufactured in FPM, PTFE, POM, PU,… on request.
Another very efficient profile in reciprocating applications is the spiral BUR made of virgin PTFE. These are two spiral windings cut at an angle at the end that can be fitted with an FPM OR when the working temperature requires it. Finally, we can highlight that BUR can be cut with different angles, which allows their assembly in closed housings.
To facilitate their identification, although obviously both the concave section rings in NBR90 and the spiral PTFE rings have very standard sizes in their respective ranges, the BS number of the AS-568 range is usually the easiest way to tie in a BUR with an OR. For example, instead of ordering a BUR which sizes are 32.16 × 3.00 × 1.00 / 1.27, it is easier to refer to the BUR218 as it will be fitted with a BS218 O-Ring (31,34×3.53).
-
What are Backup Rings (BUR)?
Published : 07/08/2022 | Categories : Back-Up RingsBUR, the O-ring's protector BURs are special rings that provide extra support for O-rings with which they are fitted. Their main purpose is to provide increased extrusion resistance and [...]