Ozone is a naturally occuring gas that is found in the air that we breathe. It consists uniquely of three oxygen molucules bonded together rather than the two of normal oxygen. Ozone is produced during lightening storms and is responsible for the fresh smell of the air afterwards. Electrical arcs from arc-welding or from around the brushes of electrical motors or ultraviolet light all produce ozone gas. It can often be detected by it's very unique chlorine bleach like smell in more concentrated form. Ozone is a powerful oxidant, so is sometimes used in air and water purification systems. To much, though, can have detrimental effects on plants, lung tissues, and organic materials like latex, plastics, and rubber.
The potential for excessive ozone concentrations is low for most environments in which belt drive systems are found. There are industrial environments, though, with higher concentrations of ozone gas making belt performance and durability a concern.
While all belts are designed for resistance to ozone, excessive concentrations can still affect rubber belts in much the same way as high environmental temperatures. Ozone slowly errodes the chemical composition resulting in rubber hardening and cracking. The amount of degradation is a function of the ozone concentration and the time of exposure. To prevent excessive detrimental effects on rubber power transmission belts, the following concentration levels should not be exceeded: (pphm = parts per hundred million)
Non-Conductive Belt Constructions: 100 pphm
Conductive Belt Constructions: 75 pphm
Non Marking Constructions: 20 pphm
Low Temperature Constructions: 20 pphm
The polyurethane material used in Poly Chain GT Carbon belts is considerably more resistant to ozone degradation than conventional rubber materials. Poly Chain GT Carbon drives are an excellent choice for drive applications located in environments with ozone concentrations.
GATES BELTS, HOSES, AND APPLICATIONS
Tuesday, January 24, 2012
Monday, January 16, 2012
Overhung Load
To prevent premature failures, manufacturers typically publish overhung load values for the speed reducers they offer. When designing a belt drive for use on a reducer, it is important to review the maximum published overhung load value to prevent overload of the bearings and shaft.
Along with their overhung load ratings, each speed reducer manufacturer publishes unique overhung load equations and constants. Therefore, it is crucial to obtain the correct overhung load calculation procedure from the reducer manufacture and to use their corresponding ratings.
If the overhung load is too high, the designer may consider increasing the pulley diameters, reducing the belt width, and/or mounting the pulley closer to the bearing. Following design adjustments, the overhung load calculations should be re-run to ensure that the drive is acceptable.
Along with their overhung load ratings, each speed reducer manufacturer publishes unique overhung load equations and constants. Therefore, it is crucial to obtain the correct overhung load calculation procedure from the reducer manufacture and to use their corresponding ratings.
If the overhung load is too high, the designer may consider increasing the pulley diameters, reducing the belt width, and/or mounting the pulley closer to the bearing. Following design adjustments, the overhung load calculations should be re-run to ensure that the drive is acceptable.
Tuesday, January 3, 2012
Right from the Start - Belt Storage
To get the most from a belt drive, its important to properly store a belt -all the proper installation procedures and design practices can be for nothing if a belt is improperly stored or damaged in storage.
A few of the major belt storage guidelines:
1) Belts can be stored up to 6 years if properly stored at temperatures less than 85 degrees F, and less than 70% relative humidty.
2) Make sure the belts are not bent to diameters smaller than the minimum recommended diameter for that cross section.
3) V-belts can be stored by hanging on a wall rack if they are hung on a saddle or diameter at least as large as the minimum diameter recommended for the cross section. Don't hang from a pin or nail!
4) Don't store in direct sunlight.
5) Don't store near heating devices.
6) Don't store near ozone generating devices such as transformers or electric motors.
7) Don't store belts where they are or could be exposed to solvents or chemicals.
8) Don't store on the floor unless in a proctive container.
9) Don't crimp belts, either in storage or handling.
Complete guidelines can be found in the Gates Belt Drive Preventive Maintenance & Safety Manual.
A few of the major belt storage guidelines:
1) Belts can be stored up to 6 years if properly stored at temperatures less than 85 degrees F, and less than 70% relative humidty.
2) Make sure the belts are not bent to diameters smaller than the minimum recommended diameter for that cross section.
3) V-belts can be stored by hanging on a wall rack if they are hung on a saddle or diameter at least as large as the minimum diameter recommended for the cross section. Don't hang from a pin or nail!
4) Don't store in direct sunlight.
5) Don't store near heating devices.
6) Don't store near ozone generating devices such as transformers or electric motors.
7) Don't store belts where they are or could be exposed to solvents or chemicals.
8) Don't store on the floor unless in a proctive container.
9) Don't crimp belts, either in storage or handling.
Complete guidelines can be found in the Gates Belt Drive Preventive Maintenance & Safety Manual.
Thursday, December 15, 2011
Interchanging Competitive Belts
Interchanging competitive belts can can be a simplified process. This site provides various interchange tools grouped by market and product type.
If a belt replacement is not listed in the interchange, Gates Application Engineers may be able to assist using measured belt dimensions. The number of teeth (synchronous belts only), length, width, and thickness can help the engineers identify the closest standard replacement.
It should be noted that replacing belts based solely on measurements is not ideal. In these cases, Gates cannot guarantee that the materials would be the same or that the belt will provide the same performance level as the original belt.
If a belt replacement is not listed in the interchange, Gates Application Engineers may be able to assist using measured belt dimensions. The number of teeth (synchronous belts only), length, width, and thickness can help the engineers identify the closest standard replacement.
It should be noted that replacing belts based solely on measurements is not ideal. In these cases, Gates cannot guarantee that the materials would be the same or that the belt will provide the same performance level as the original belt.
Wednesday, December 14, 2011
Belt Drives and Oil Contamination
Belt drive contamination with oil is never beneficial, but sometimes cannot be avoided. While occasional contact does not generally have adverse effects, prolonged contact with oil type lubricants, either directly or airborne, causes rubber compounds to soften and swell. Adhesion systems internal to belts are also weakened and broken down. This ultimately results in significantly reduced belt service life.
V-belt drives rely exclusively on friction to transmit power, so any contaminants that reduce friction also reduce the ability of the belt drive to transmit power. Banded type V-belts might have slightly improved resistance, compared to "raw edge" or "cut edge" type V-belts, with the outside cover temporarily shielding internal components. Also, neoprene based V-belts will have greater resistance to oil than EPDM based V-belts.
Synchronous belt drives rely less on friction to transmit power than V-belt drives. They also tend to perform better in oil contaminated environments. Rubber based synchronous belts, however, are still susceptible to swelling and adhesion system breakdown over time. While alternate rubber compounds may provide some marginal improvement in durability, it is best to prevent oil from contacting rubber synchronous belts if possible.
Gates Poly Chain type belts use a urethane based construction that is quite resistant to oil contamination. This prevents material swelling and breakdown that cannot be avoided with rubber materials. Note that synchronous belts still rely on friction to transmit power, so lubrications will interfere with power transmission. Poly Chain GT Carbon belts are used successfully in environments with heavy misting of oil based lubricants and cutting fluids, and have even been submerged in oil. Poly Chain GT Carbon belts are the best bet for applications that cannot avoid oil contamination.
V-belt drives rely exclusively on friction to transmit power, so any contaminants that reduce friction also reduce the ability of the belt drive to transmit power. Banded type V-belts might have slightly improved resistance, compared to "raw edge" or "cut edge" type V-belts, with the outside cover temporarily shielding internal components. Also, neoprene based V-belts will have greater resistance to oil than EPDM based V-belts.
Synchronous belt drives rely less on friction to transmit power than V-belt drives. They also tend to perform better in oil contaminated environments. Rubber based synchronous belts, however, are still susceptible to swelling and adhesion system breakdown over time. While alternate rubber compounds may provide some marginal improvement in durability, it is best to prevent oil from contacting rubber synchronous belts if possible.
Gates Poly Chain type belts use a urethane based construction that is quite resistant to oil contamination. This prevents material swelling and breakdown that cannot be avoided with rubber materials. Note that synchronous belts still rely on friction to transmit power, so lubrications will interfere with power transmission. Poly Chain GT Carbon belts are used successfully in environments with heavy misting of oil based lubricants and cutting fluids, and have even been submerged in oil. Poly Chain GT Carbon belts are the best bet for applications that cannot avoid oil contamination.
Tuesday, November 8, 2011
Micro-V Belts
Gates has a line of belts that we call Micro-V. They are called this because the belt is made up of a band of small V-belts put together. They are also called Poly-V belts by others in the industry. These belts are actually very common, in fact, you may have worked on one, and not even known it! Micro-V belts come in different sizes, or sections. One of these sections is called K-section, this is the type of belt that runs the accessory drives (alternator, water pump, etc…) under the hood of your car. While they are commonly called serpentine because of the way that they move around the pulleys, these are in fact K-section Micro-V belts. K-section belts are mainly used on automobiles and industrial gasoline and diesel motors. The less known sections of Micro-V’s include H, J, L, and M sections. H section is very small, and is typically not used for design except by large OE’s. J , L, and M section belts are the standard industrial line that we can help you design with. These belts push a lot of power for their size, are quiet, and can handle higher speeds well. One thing to keep in mind, however, is that we don’t have any off the shelf pulleys for them. This means that you would either need to have something made to order, or you could contact us for the groove information to create your own pulleys. You can find more information about these belts in our Light Power and Precision Drive Design Manual or as always by contacting us directly.
Thursday, November 3, 2011
Water & Synchronous Belt Resistance
Light and occasional contact with water, such as occasional wash downs, should not generally affect synchronous belts seriously. Prolonged contact such as spray or submersion, however, can have detrimental effects.Rubber synchronous belts are considerably more vulnerable than Poly Chain GT Carbon belts.
With rubber synchronous belts, water soaking reduces the tensile strength of fiberglass tensile cords in addition to breaking down adhesion systems between the cord and the rubber compound. While aramid type tensile cords are more resistant to water than fiberglass, they are dimensionally unstable in the presence of water or humidity, so can result in belt length stability problems. Soaking also causes the rubber body to swell, lesser than but similar to oil contamination. This can negatively impact belt pitch fit with pulleys and sprockets in addition to material weakening. Additives to water such as lubricants, chlorine, anti-corrosives, etc. can intensify detrimental affects of water soaking.
Poly Chain GT Carbon belts are quite resistant to water soaking, and have even been used successfully in submerged applications. While urethane can exhibit a small amount of swelling, overall belt performance and the ability to transmit power remains relatively stable.
When considering the use of synchronous belt drive systems in moist or wet environments, the resistance of the hardware to corrosion is also very important. Coatings or treatments used on standard iron based hardware may not have adequate corrosion resistance. Special corrosion resistant coatings such as zinc or nickel plating are available on a made-to-order basis.
Contact our Made-To-Order Metals Group at (800) 709-6001 for further information about hardware corrosion protection options. Contact our Product Application Engineering Group at (303) 744-5800 for further information about applying belt drive systems in adverse environments.
![Poly Chain GT Carbon belts are quite resistant to water soaking, and have even been used successfully in submerged applications.]()
With rubber synchronous belts, water soaking reduces the tensile strength of fiberglass tensile cords in addition to breaking down adhesion systems between the cord and the rubber compound. While aramid type tensile cords are more resistant to water than fiberglass, they are dimensionally unstable in the presence of water or humidity, so can result in belt length stability problems. Soaking also causes the rubber body to swell, lesser than but similar to oil contamination. This can negatively impact belt pitch fit with pulleys and sprockets in addition to material weakening. Additives to water such as lubricants, chlorine, anti-corrosives, etc. can intensify detrimental affects of water soaking.
Poly Chain GT Carbon belts are quite resistant to water soaking, and have even been used successfully in submerged applications. While urethane can exhibit a small amount of swelling, overall belt performance and the ability to transmit power remains relatively stable.
When considering the use of synchronous belt drive systems in moist or wet environments, the resistance of the hardware to corrosion is also very important. Coatings or treatments used on standard iron based hardware may not have adequate corrosion resistance. Special corrosion resistant coatings such as zinc or nickel plating are available on a made-to-order basis.
Contact our Made-To-Order Metals Group at (800) 709-6001 for further information about hardware corrosion protection options. Contact our Product Application Engineering Group at (303) 744-5800 for further information about applying belt drive systems in adverse environments.
Subscribe to:
Posts (Atom)