TIMMYLITK

Fewer bearing replacements and less maintenance

Plummer block housings have much to offer

The main benefit of split plummer blocks housings is their easy installation; pre-assembled shafts can be mounted in them, when the housing bases are attached to the base plate it is then only necessary to place the housing caps in position and to tighten the attachment bolts to complete the installation.

Split plummer block housings available on the market are mainly intended for self-aligning ball bearings, spherical roller bearings and CARB^®bearings of ISO dimension series 02,03,22,23,30,31,32,39,40,and 41. They can often be fitted with various different seals. Many designs and variants of split plummer block housings are available making the use of tailored housings unnecessary and thus enabling cost effective bearing arrangements to be made.

For many years SKF has been one of the leading suppliers of various designs of split plummer block housingsm including the SD plummer block housings-synonymous with operational reliability and quality,

SNL 30 and SNL 31 plummer block housings have more to offer

SKF plummer block housings of the SD design are currently being redesigned to take advantage of the progress embodied in the smaller SNL housings. The new plummer block housings of series SNL30 and SNL31 will gradually replace the SD housings and are also referred to as “Lager SNL plummer block housings”.

The new SNL plummer blocks housings enable the full service life potential of the incorporated bearings to be exploited with less need of maintenance. This supports user efforts to further reduce maintenance costs. Among other enhancements the SNL housings have a new external design for easier alignment and handling when mounting.

Another benefit is the choice of oil or grease lubrication for the bearings housed in SNL plummer blocks. A range of newly developed seals for oil lubrication and rough environments make for trouble-free operation.

One basic design-many variants

Lager SNL plummer block housings are primarily intended for spherical roller bearings and CARB bearings. The housings are designed on a” building block” principle. This enables a more generous choice of bearing, shaft mounting, seals and type of lubrication.

A building block system

The basis of the original SNL plummer block housing system consists of a number of housings of the same design but in different sizes. By combining the housings with the different standard seals a wide variety of housing variants, all belonging to the standard range can be supplied to cover the majority of demands for plummer blocks.

When complete, the new range of series SNL 30 and SNL 31 will be available for shafts having diameters of 150 to 500mm, inclusive. However, initially the range extends to shaft sizes up to 300mm; the lager sizes will gradually becomes available as design work is completed. The availability of housings for which only shaft size and designations are given in the product tables should be checked before ordering.

The standard range will also cover housings with drilled and tapped holes for lubrication nipples. There are variants to be drilled upon request for condition monitoring.

Series SNL30 and SNL31 plummer block housings are made of grey cast iron and demonstrate the same high strength as the earlier SD housings. Should, however, this strength be inadequate, dimensionally equivalent SNLD plummer block housings of spherical graphite cast iron are available.

The large SNL and SNLD plummer block housings are fully interchangeable with the earlier SD and SDD housings. Their dimensions conform to ISO 13:1999.

Several sealing options

An important advantage of the SNL plummer block housings is that they can be fitted with different seals. The standard seals supplied by SKF for the large SNL30 and SNL31 series housings comprise labyrinth seals and heavy-duty “taconite”seals as well as end covers. There is also an oil seal available but this sealing arrangement is sipplied together with the housing as the housing has to be modified to take it.

Costs and risks – at a low level

The new SNL 30 and SNL 31 plummer block housings represent a further development of the SD housings.

There large SNL housings have several special features as well as sealing alternatives.

Reinforced square base

The housing base is reinforced with walls around the holes for the attachment bolts in order to provide improved seating on the base plate. The attachment bolts can be preloaded to give better location and can no longer deform the housing bore.

Enlarged contact area

The center cross reinforcement of the housing base enlarges the contact area between base and base plate and allows for an improved heat flow from the bearing outer ring to the base plate.

Drilled and tapped holes

Housings have drilled and tapped holes as standard in the cap. The holes are protected by metallic plugs. Two nipples are supplied, together with nipple protector and adapter, with the housing(packed inside). If the application is such that relubrication is required it is only necessary to screw the nipples into the holes and lubricant can be supplied to one side of the bearing or in the W33 groove. There are also indications on the housing where holes can be drilled for lubrication of the seals.’

Caps and bases individually marked

The housings base and cap are matched during manufacture and are not interchangeable with the caps and bases of other housings. To prevent mixing caps and bases when mounting several housings, the same consecutive number is marked on the cap and base of each individual housings