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Maximum Cleaving potential for extreme environments
Maximum Cleaving potential for extreme environments
Designed for use in especially tough applications and in particular, where the adhesive bond between contaminant and rod surface is strong. The wider and deeper cross-section of D-Series cleavers deliver a strong force to break the bonds between contaminants, and the rod surface. The larger cross-section allows for the addition of an oring to seal the OD plus a heavy-duty stainless steel spring. The groove size and breakout friction constraints placed on the designs of other scraper specifications, are ignored in this aggressive and rugged design resulting in a "no-holds-barred" solution to tough contaminants. D-Series cleavers are available in ductile copper alloys and Stainless Steel alloys for sizes from 20mm to 250mm (smaller, larger and in-between sizes available upon request).
Style-I
Style-I
The large cross-section provides more resistance to the forces generated by contaminants presenting at the interface of the lip on the scraper body, and the surface of the rod. These forces are inclined to "lift" the seal body away from the rod surface, undermining the action. The heavier body of the cleaver provides greater resistance to these lifting forces by permitting the use of a heavier serpentine spring, generating more clamping load to further resist the over-ride of strongly bonded (adhered) contaminants. These forces are surprisingly large in magnitude and a combination of body rigidity, spring loading, interference with the gland, generated through the compressed oring, all contribute to overcome such forces.
Style-II
Style-II
Style II D-Series metal cleavers contain a high load serpentine spring, paired with an oring that protrudes approximately 0.02" beyond the OD of the scraper body to seal against the gland and prevent an outer ingression path. The combination of spring loading and o-ring compression (interference) results in the highest performing exclusion-seal design.
Style-S
Style-S
Style-S D-series cleavers contain a slotted heel to provide a path of egress for contaminants that bypass the seal and accumulate between the cleaver and wiper. The slot allows fine contaminant particles to flow over the lip of the wiper to a void between the face of the wiper and back of the scraper. Further consideration should be given by the Design Engineer, to the further accumulation of these particles.
Style-L
Style-L
This seal contains a large cross-section oring which is designed to create sufficient interference against a standard lip at the aperture of the retaining groove (counter-bore) so as to permit a 'snap-in' type of installation.
DIMENSIONS
DIMENSIONS
Style I shown above - dimensions apply to all styles.
D-Series rod cleavers are available for rod sizes up to and beyond 13" (310mm) dia. The following is a partial list of part/groove dimensions. For a more complete list, or for specific parts, please contact us.
Rod Compatibility & Testing for D-Series Cleavers
Rod Compatibility & Testing for D-Series Cleavers
The following are general guidelines and are not intended to supersede information gathered from application and equipment specific testing.
Gadjets recommends testing of all exclusion seals, in the actual environment, on the actual equipment, prior to placing into service. The performance of a rod scraper or metal wiper depends very much upon present environmental factors, the method of installation and retention including considerations such as the clearances provided, especially to protect against bearing of sideload and shock loads, the presence or absence of a cohesive oil film on the surface of the rod/sleeve, as well as the condition and functioning of any adjacent seals. It depends on the condition of the rod, the nature and type of contaminants and other environmental factors such as temperature, pressure, moisture and atmosphere.
Some general recommendations based on field observation include:
Rod cleavers can be expected to work best on relatively hard rod surfaces, including hard chromed and nitrided rods etc.
For copper alloy scrapers, a hardness of 60+ (Rockwell C scale) is recommended.
For Stainless Steel cleavers, a hardness of 70+ (Rockwell C scale) is recommended. Stainless Steel does have a propensity to gall if paired with materials similar in crystalline structure, (especially other Stainless Steels) or on poorer finishes or softer coatings.
Recommended surface finish range is 0.1 to 0.3 μm Ra (4-12 μin Ra), ideally, honed or burnished rod stock - less than 0.1μm Ra) (4 μin Ra).
For the first few cycles of the cleaver assembly on a super-finished rod, linear (axial) witness marks are likely to be observed on the surface of the rod. Typically witness marks will "polish out" as a result of the seal acting on the rod during the first few hundred cycles and should not impact performance.
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