Ralphs-Pugh offers a wide selection of bearings to match the user’s conveyor roller requirements. Our offering includes commercial grade and precision bearings in metal and plastic housings. Commercial grade bearings are recommended for lower speeds and lighter load applications. Precision Bearings (ABEC-1) are the best choice for higher speeds. For corrosive and wash-down environments, stainless steel bearings are often specified. We design and build all our plastic housed bearings in our facility to ensure the highest quality available.
Plated Steel/Metal Housings
These bearings are manufactured utilising hardened steel balls and raceways. The outer raceway is either stamped or machined and lubricated with light oil. Grease packed bearings may be ordered for driven systems.
Plated Steel/Plastic Housings
Designed for light to moderate loads, the plastic housed bearings have hardened steel balls and stamped or machined inner and outer raceways. They are available with light oil or grease lubricant for driven systems. Plastic housings are available in conductive or non-conductive material with or without labyrinth seals. The labyrinth seal(s) provide protection to the bearing from dust, dirt, and airborne debris.
Stainless Steel/Plastic Housings
Designed for light to moderate loads, stainless steel balls and raceways provide an excellent solution for corrosive operating environments. For maximum protection against contamination, housing may be ordered with a double labyrinth seal system. Other housings are also available.
Precision Grade / ABEC-1
Designed for higher speeds and heavier loads, ABEC-1 precision bearings are available in chromium steel and optional 440, 304 or 316 stainless steel. ABEC-1 ball bearings and raceways are hardened, precision ground, and incorporate a ball retainer to eliminate bearing-to-bearing contact. Bearings are factory lubricated and sealed. Several seal/shield configurations are offered. Standard configuration is the LLB, Non-Contact Rubber Seal. Options include; 2RS Contact Rubber Seal and the ZZ Non-Contact Metal Shield. Bearing housings are available in metal or plastic. Plastic housings are made with conductive materials and available with or without labyrinth seals. Labyrinth seals provide additional bearing protection against dirt, dust, and other airborne contaminates. ABEC-1 bearings provide the highest load and speed capabilities, the lowest noise levels, and the longest life span of any available bearing unit.
These non-ball bearing units are designed for light to medium loads and slow speeds. Typical installations are push conveyors and gravity conveyors. These are ideal for sanitary, rust and corrosion resistant, maintenance free wet or dry applications. Bearing materials include Ultra (Acetal plastic with Teflon internal lubricants), CS2 (Acetal), UHMW and ABS plastic. Bushing adapters include nylon, stainless steel, carbon steel and Ultra.
What Is Static Electricity?
It’s what the name implies, electricity at rest. This electrical charge is the result of a transfer of electrons that occurs due to the sliding, rubbing, turning or separating of a material, which is a prime generator of electrostatic voltages – e.g.: plastics, fiberglass, rubber, textiles, etc. Under the right conditions, this induced charge can build to 30,000 – 40,000 volts.
When this happens to an insulating material, such as a plastic, the built-up charge tends to remain in the localized area of contact. This electrostatic voltage then can discharge via an arc or spark when the plastic material comes in contact with a body at a sufficiently different potential, such as a person or microcircuit.
If electrostatic discharge (ESD) occurs to a person, the result can range from a mild shock to a very painful shock. In extreme cases, ESD could even result in the loss of life. Sparks are dangerous in an environment containing flammable liquids, solids or gases, such as in a hospital operating room, grain elevator or during the assembly of explosive devices.
Some micro-electronic parts can be destroyed or damaged by ESD as low as 20 volts. Since people are prime causes of ESD, they often cause damage to sensitive electronic parts, especially during manufacturing and assembly.
Plastics are classified as insulating materials having typical surface resistivities of 1016 – 1017 ohms/sq. The electrically conductive plastics commercially available today are composite materials of electrically insulating base resins and electrically conductive fillers or reinforcing agents. Electrical conductivity is achieved via a conductive network of particles or fibers. For electrically conductive plastics, three different conductivity ranges are defined:
- Dissipative Composites
- Conductive Composites
- ESD shielding Composites