Screw conveyors rely on robust hanger bearings to maintain smooth rotation, prevent misalignment, and extend service life in challenging environments. This guide highlights top Sealmaster NP pillow block bearings suited for normal-duty, non-expansion screw conveyor applications. Each entry focuses on reliability, ease of installation, and endurance under radial and thrust loads. The selections below help you compare common bore sizes and base heights to match your conveyor design and shaft requirements.
Overview table of selected products (summary only):
| Product | Bore | Base To Center Height | Bolt Hole Spacing |
|---|---|---|---|
| Sealmaster NP-24 Pillow Block | 1-1/2″ | 1-15/16″ | 5-3/8″ |
| Sealmaster NP-16 Pillow Block | 1″ | 1-7/16″ | 4-1/8″ |
| Sealmaster NP-27 Pillow Block | 1-11/16″ | 2-1/8″ | 5-3/4″ |
| Sealmaster NP-12 Pillow Block | 3/4″ | 1-5/16″ | 3-3/4″ |
| Sealmaster NP-19 Pillow Block | 1-3/16″ | 1-11/16″ | 4-3/4″ |
Sealmaster NP-24 Pillow Block
The NP-24 piece uses a cast iron housing paired with a robust steel bearing unit designed to support shafts under radial or combined radial and thrust loads. It is a relubricatable, solid one-piece pillow block with a two-bolt mounting interface that facilitates quick installation and consistent alignment. This model includes a 1-1/2″ bore and a base-to-center height suited for many screw conveyor hangers that demand rigidity in normal-duty service.
Sealmaster NP-16 Pillow Block
Designed for compact spaces, the NP-16 offers a 1″ bore with a base-to-center height of 1-7/16″ and 4-1/8″ bolt hole spacing. Its two-bolt housing delivers straightforward mounting for quick swaps and service. The cast iron housing and steel bearing unit tolerate radial loads well, making it suitable for smaller screw conveyors or light-duty reenforcement roles within a system that requires dependable support with minimal footprint.
Sealmaster NP-27 Pillow Block
The NP-27 features a larger bore of 1-11/16″ and a higher base-to-center height of 2-1/8″, with a 5-3/4″ bolt hole spacing. Its two-bolt housing and relubricatable pillar provide strong mounting for mid-range loads, making it a practical option for screw conveyors that demand robust alignment across longer spans or higher torque. The combination of cast iron housing and steel bearing unit helps manage radial loads efficiently while maintaining rigidity under dynamic operation.
Sealmaster NP-12 Pillow Block
The NP-12 offers compact dimensions with a 3/4″ bore and a base-to-center height of 1-5/16″. Its small footprint and light weight are ideal for low-profile conveyor sections or retrofits where height clearance is at a premium. The pillow block maintains strong support for shafts against radial loads, with a reliable two-bolt mounting pattern that ensures straightforward installation and alignment without sacrificing rigidity.
Sealmaster NP-19 Pillow Block
With a 1-3/16″ bore and a base-to-center height of 1-11/16″, the NP-19 is a mid-range option that balances mounting compactness with generous bearing support. A 4-3/4″ bolt hole spacing and two-bolt housing contribute to stable alignment for moderate-load screw conveyors. This model combines reliability with a design that supports both radial and thrust loading in normal-duty applications.
Sealmaster NP-20 Pillow Block
The NP-20 applies to 1-1/4″ bore with a base-to-center height of 1-7/8″ and 5″ bolt hole spacing. This size sits between compact and larger pillow blocks, offering versatile mounting for various screw conveyor configurations. Its two-bolt housing and relubricatable construction deliver long-term performance under radial and thrust load conditions while maintaining alignment over time.
Sealmaster NP-28 Pillow Block
The NP-28 offers a 1-3/4″ bore with a base-to-center height of 2-1/8″ and a 5-3/4″ bolt hole spacing. It provides strong support for mid-to-large diameter shafts, making it well suited for robust screw conveyors in industrial settings. The two-bolt housing, relubricatable design, and cast iron housing together improve rigidity and load handling while enabling straightforward installation and maintenance in demanding applications.
Sealmaster NP-39 Pillow Block
The NP-39 is designed for larger bore and greater base-to-center height, with a 2-7/16″ bore and 2-3/4″ height, plus a wide 7-1/4″ bolt hole spacing. This model is appropriate for high-load screw conveyors or systems with extended shafts requiring substantial support. It maintains the standard two-bolt mounting with a robust relubricatable housing for consistent performance in normal-duty operation.
Buying Guide: Key Considerations For Screw Conveyor Hanger Bearings
When selecting hanger bearings for screw conveyors, several factors influence performance and longevity. The following perspectives help stakeholders assess options without relying on price alone.
- Load capacity: Assess radial and thrust loads expected during conveyor operation. Higher bore sizes and larger base-to-center heights generally support greater loads but require more space and precise alignment.
- Material and housing: Cast iron housings offer durability and rigidity, while steel bearing units provide strong support for shafts exposed to continuous rotation and vibrations.
- Lubrication: Relubricatable pillow blocks simplify maintenance and extend life in environments with dust, moisture, or contaminants. Consider lubricant type and interval scheduling.
- Mounting geometry: Two-bolt housings are common and straightforward to install; ensure bolt hole spacing and mounting footprint align with your conveyor frame and support structure.
- Shaft compatibility: Confirm bore size matches your shaft diameter and tolerance class. Mismatches can cause binding, wear, or misalignment.
- Mounting height and clearance: Base-to-center height affects conveyor layout and belt tensioning. Larger heights support longer shafts but require more vertical space.
- Maintenance access: Choose designs that allow easy lubrication and inspection without disassembly of major components.
- Availability of spare parts: Look for widely-used models with readily available replacements or rebuild kits to minimize downtime.
- Operational environment: Consider temperature, dust, moisture, and chemical exposure. Some seals and materials perform better in harsh settings.
In practice, you should map your conveyor’s shaft diameter, desired alignment tolerance, and mounting footprint to a handful of suitable NP pillow block models. Compare bore size, base height, and bolt spacing to determine which option best fits your frame. For mid-range applications, the NP-20 and NP-27 sizes commonly balance space constraints with load needs, while NP-24 and NP-28 suit larger shafts and higher torque scenarios. Always verify installation clearances and lubrication access during planning.
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