B Series Short pitch Precision Triplex Roller Chains & Bush Chains
|Width between inner plates
|Pin length||Inner plate depth
|Average tensile strength
|Weight per meter
*Straight side plates
Roller chain or bush roller chain is the type of chain drive most commonly used for transmission of mechanical power on many kinds of domestic, industrial and agricultural machinery, including conveyors, wire- and tube-drawing machines, printing presses, cars, motorcycles, and bicycles. It consists of a series of short cylindrical rollers held together by side links. It is driven by a toothed wheel called a sprocket. It is a simple, reliable, and efficient means of power transmission.
CONSTRUCTION OF THE CHAIN
Two different sizes of roller chain, showing construction.
There are 2 types of links alternating in the bush roller chain. The first type is inner links, having 2 inner plates held together by 2 sleeves or bushings CZPT which rotate 2 rollers. Inner links alternate with the second type, the outer links, consisting of 2 outer plates held together by pins passing through the bushings of the inner links. The “bushingless” roller chain is similar in operation though not in construction; instead of separate bushings or sleeves holding the inner plates together, the plate has a tube stamped into it protruding from the hole which serves the same purpose. This has the advantage of removing 1 step in assembly of the chain.
The roller chain design reduces friction compared to simpler designs, resulting in higher efficiency and less wear. The original power transmission chain varieties lacked rollers and bushings, with both the inner and outer plates held by pins which directly contacted the sprocket teeth; however this configuration exhibited extremely rapid wear of both the sprocket teeth, and the plates where they pivoted on the pins. This problem was partially solved by the development of bushed chains, with the pins holding the outer plates passing through bushings or sleeves connecting the inner plates. This distributed the wear over a greater area; however the teeth of the sprockets still wore more rapidly than is desirable, from the sliding friction against the bushings. The addition of rollers surrounding the bushing sleeves of the chain and provided rolling contact with the teeth of the sprockets resulting in excellent resistance to wear of both sprockets and chain as well. There is even very low friction, as long as the chain is sufficiently lubricated. Continuous, clean, lubrication of roller chains is of primary importance for efficient operation as well as correct tensioning.
Many driving chains (for example, in factory equipment, or driving a camshaft inside an internal combustion engine) operate in clean environments, and thus the wearing surfaces (that is, the pins and bushings) are safe from precipitation and airborne grit, many even in a sealed environment such as an oil bath. Some roller chains are designed to have o-rings built into the space between the outside link plate and the inside roller link plates. Chain manufacturers began to include this feature in 1971 after the application was invented by Joseph Montano while working for Whitney Chain of Hartford, Connecticut. O-rings were included as a way to improve lubrication to the links of power transmission chains, a service that is vitally important to extending their working life. These rubber fixtures form a barrier that holds factory applied lubricating grease inside the pin and bushing wear areas. Further, the rubber o-rings prevent dirt and other contaminants from entering inside the chain linkages, where such particles would otherwise cause significant wear.
There are also many chains that have to operate in dirty conditions, and for size or operational reasons cannot be sealed. Examples include chains on farm equipment, bicycles, and chain saws. These chains will necessarily have relatively high rates of wear, particularly when the operators are prepared to accept more friction, less efficiency, more noise and more frequent replacement as they neglect lubrication and adjustment.
Many oil-based lubricants attract dirt and other particles, eventually forming an CZPT paste that will compound wear on chains. This problem can be circumvented by use of a “dry” PTFE spray, which forms a solid film after application and repels both particles and moisture.
Layout of a roller chain: 1. Outer plate, 2. Inner plate, 3. Pin, 4. Bushing, 5. Roller
If the chain is not being used for a high wear application (for instance if it is just transmitting motion from a hand-operated lever to a control shaft on a machine, or a sliding door on an oven), then 1 of the simpler types of chain may still be used. Conversely, where extra strength but the smooth drive of a smaller pitch is required, the chain may be “siamesed”; instead of just 2 rows of plates on the outer sides of the chain, there may be 3 (“duplex”), 4 (“triplex”), or more rows of plates running parallel, with bushings and rollers between each adjacent pair, and the same number of rows of teeth running in parallel on the sprockets to match. Timing chains on automotive engines, for example, typically have multiple rows of plates called strands.
Roller chain is made in several sizes, the most common American National Standards Institute (ANSI) standards being 40, 50, 60, and 80. The first digit(s) indicate the pitch of the chain in eighths of an inch, with the last digit being 0 for standard chain, 1 for lightweight chain, and 5 for bushed chain with no rollers. Thus, a chain with half-inch pitch would be a #40 while a #160 sprocket would have teeth spaced 2 inches apart, etc. Metric pitches are expressed in sixteenths of an inch; thus a metric #8 chain (08B-1) would be equivalent to an ANSI #40. Most roller chain is made from plain carbon or alloy steel, but stainless steel is used in food processing machinery or other places where lubrication is a problem, and nylon or brass are occasionally seen for the same reason.
Roller chain is ordinarily hooked up using a master link (also known as a connecting link), which typically has 1 pin held by a horseshoe clip rather than friction fit, allowing it to be inserted or removed with simple tools. Chain with a removable link or pin is also known as cottered chain, which allows the length of the chain to be adjusted. Half links (also known as offsets) are available and are used to increase the length of the chain by a single roller. Riveted roller chain has the master link (also known as a connecting link) “riveted” or mashed on the ends. These pins are made to be durable and are not removable.
An example of 2 ‘ghost’ sprockets tensioning a triplex roller chain system
Roller chains are used in low- to mid-speed drives at around 600 to 800 feet per minute; however, at higher speeds, around 2,000 to 3,000 feet per minute, V-belts are normally used due to wear and noise issues.
A bicycle chain is a form of roller chain. Bicycle chains may have a master link, or may require a chain tool for removal and installation. A similar but larger and thus stronger chain is used on most motorcycles although it is sometimes replaced by either a toothed belt or a shaft drive, which offer lower noise level and fewer maintenance requirements.
The great majority of automobile engines use roller chains to drive the camshaft(s). Very high performance engines often use gear drive, and starting in the early 1960s toothed belts were used by some manufacturers.
Chains are also used in forklifts using hydraulic rams as a pulley to raise and lower the carriage; however, these chains are not considered roller chains, but are classified as lift or leaf chains.
Chainsaw cutting chains superficially resemble roller chains but are more closely related to leaf chains. They are driven by projecting drive links which also serve to locate the chain CZPT the bar.
Sea Harrier FA.2 ZA195 front (cold) vector thrust nozzle – the nozzle is rotated by a chain drive from an air motor
A perhaps unusual use of a pair of motorcycle chains is in the Harrier Jump Jet, where a chain drive from an air motor is used to rotate the movable engine nozzles, allowing them to be pointed downwards for hovering flight, or to the rear for normal CZPT flight, a system known as Thrust vectoring.
The effect of wear on a roller chain is to increase the pitch (spacing of the links), causing the chain to grow longer. Note that this is due to wear at the pivoting pins and bushes, not from actual stretching of the metal (as does happen to some flexible steel components such as the hand-brake cable of a motor vehicle).
With modern chains it is unusual for a chain (other than that of a bicycle) to wear until it breaks, since a worn chain leads to the rapid onset of wear on the teeth of the sprockets, with ultimate failure being the loss of all the teeth on the sprocket. The sprockets (in particular the smaller of the two) suffer a grinding motion that puts a characteristic hook shape into the driven face of the teeth. (This effect is made worse by a chain improperly tensioned, but is unavoidable no matter what care is taken). The worn teeth (and chain) no longer provides smooth transmission of power and this may become evident from the noise, the vibration or (in car engines using a timing chain) the variation in ignition timing seen with a timing light. Both sprockets and chain should be replaced in these cases, since a new chain on worn sprockets will not last long. However, in less severe cases it may be possible to save the larger of the 2 sprockets, since it is always the smaller 1 that suffers the most wear. Only in very light-weight applications such as a bicycle, or in extreme cases of improper tension, will the chain normally jump off the sprockets.
The lengthening due to wear of a chain is calculated by the following formula:
M = the length of a number of links measured
S = the number of links measured
P = Pitch
In industry, it is usual to monitor the movement of the chain tensioner (whether manual or automatic) or the exact length of a drive chain (one rule of thumb is to replace a roller chain which has elongated 3% on an adjustable drive or 1.5% on a fixed-center drive). A simpler method, particularly suitable for the cycle or motorcycle user, is to attempt to pull the chain away from the larger of the 2 sprockets, whilst ensuring the chain is taut. Any significant movement (e.g. making it possible to see through a gap) probably indicates a chain worn up to and beyond the limit. Sprocket damage will result if the problem is ignored. Sprocket wear cancels this effect, and may mask chain wear.
The most common measure of roller chain’s strength is tensile strength. Tensile strength represents how much load a chain can withstand under a one-time load before breaking. Just as important as tensile strength is a chain’s fatigue strength. The critical factors in a chain’s fatigue strength is the quality of steel used to manufacture the chain, the heat treatment of the chain components, the quality of the pitch hole fabrication of the linkplates, and the type of shot plus the intensity of shot peen coverage on the linkplates. Other factors can include the thickness of the linkplates and the design (contour) of the linkplates. The rule of thumb for roller chain operating on a continuous drive is for the chain load to not exceed a mere 1/6 or 1/9 of the chain’s tensile strength, depending on the type of master links used (press-fit vs. slip-fit). Roller chains operating on a continuous drive beyond these thresholds can and typically do fail prematurely via linkplate fatigue failure.
The standard minimum ultimate strength of the ANSI 29.1 steel chain is 12,500 x (pitch, in inches)2. X-ring and O-Ring chains greatly decrease wear by means of internal lubricants, increasing chain life. The internal lubrication is inserted by means of a vacuum when riveting the chain together.
Standards organizations (such as ANSI and ISO) maintain standards for design, dimensions, and interchangeability of transmission chains. For example, the following Table shows data from ANSI standard B29.1-2011 (Precision Power Transmission Roller Chains, Attachments, and Sprockets) developed by the American Society of Mechanical Engineers (ASME). See the references for additional information.
ASME/ANSI B29.1-2011 Roller Chain Standard SizesSizePitchMaximum Roller DiameterMinimum Ultimate Tensile StrengthMeasuring Load25
|ASME/ANSI B29.1-2011 Roller Chain Standard Sizes|
|Size||Pitch||Maximum Roller Diameter||Minimum Ultimate Tensile Strength||Measuring Load|
|25||0.250 in (6.35 mm)||0.130 in (3.30 mm)||780 lb (350 kg)||18 lb (8.2 kg)|
|35||0.375 in (9.53 mm)||0.200 in (5.08 mm)||1,760 lb (800 kg)||18 lb (8.2 kg)|
|41||0.500 in (12.70 mm)||0.306 in (7.77 mm)||1,500 lb (680 kg)||18 lb (8.2 kg)|
|40||0.500 in (12.70 mm)||0.312 in (7.92 mm)||3,125 lb (1,417 kg)||31 lb (14 kg)|
|50||0.625 in (15.88 mm)||0.400 in (10.16 mm)||4,880 lb (2,210 kg)||49 lb (22 kg)|
|60||0.750 in (19.05 mm)||0.469 in (11.91 mm)||7,030 lb (3,190 kg)||70 lb (32 kg)|
|80||1.000 in (25.40 mm)||0.625 in (15.88 mm)||12,500 lb (5,700 kg)||125 lb (57 kg)|
|100||1.250 in (31.75 mm)||0.750 in (19.05 mm)||19,531 lb (8,859 kg)||195 lb (88 kg)|
|120||1.500 in (38.10 mm)||0.875 in (22.23 mm)||28,125 lb (12,757 kg)||281 lb (127 kg)|
|140||1.750 in (44.45 mm)||1.000 in (25.40 mm)||38,280 lb (17,360 kg)||383 lb (174 kg)|
|160||2.000 in (50.80 mm)||1.125 in (28.58 mm)||50,000 lb (23,000 kg)||500 lb (230 kg)|
|180||2.250 in (57.15 mm)||1.460 in (37.08 mm)||63,280 lb (28,700 kg)||633 lb (287 kg)|
|200||2.500 in (63.50 mm)||1.562 in (39.67 mm)||78,175 lb (35,460 kg)||781 lb (354 kg)|
|240||3.000 in (76.20 mm)||1.875 in (47.63 mm)||112,500 lb (51,000 kg)||1,000 lb (450 kg|
For mnemonic purposes, below is another presentation of key dimensions from the same standard, expressed in fractions of an inch (which was part of the thinking behind the choice of preferred numbers in the ANSI standard):
|Pitch (inches)||Pitch expressed
1. The pitch is the distance between roller centers. The width is the distance between the link plates (i.e. slightly more than the roller width to allow for clearance).
2. The right-hand digit of the standard denotes 0 = normal chain, 1 = lightweight chain, 5 = rollerless bushing chain.
3. The left-hand digit denotes the number of eighths of an inch that make up the pitch.
4. An “H” following the standard number denotes heavyweight chain. A hyphenated number following the standard number denotes double-strand (2), triple-strand (3), and so on. Thus 60H-3 denotes number 60 heavyweight triple-strand chain.
A typical bicycle chain (for derailleur gears) uses narrow 1⁄2-inch-pitch chain. The width of the chain is variable, and does not affect the load capacity. The more sprockets at the rear wheel (historically 3-6, nowadays 7-12 sprockets), the narrower the chain. Chains are sold according to the number of speeds they are designed to work with, for example, “10 speed chain”. Hub gear or single speed bicycles use 1/2″ x 1/8″ chains, where 1/8″ refers to the maximum thickness of a sprocket that can be used with the chain.
Typically chains with parallel shaped links have an even number of links, with each narrow link followed by a broad one. Chains built up with a uniform type of link, narrow at 1 and broad at the other end, can be made with an odd number of links, which can be an advantage to adapt to a special chainwheel-distance; on the other side such a chain tends to be not so strong.
Roller chains made using ISO standard are sometimes called as isochains.
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|Standard or Nonstandard:||Standard, Standard|
|Application:||Textile Machinery, Garment Machinery, Conveyer Equipment, Packaging Machinery, Electric Cars, Motorcycle, Food Machinery, Marine, Mining Equipment, Agricultural Machinery, Car, Textile Machinery, Garment Machinery, Conveyer Equipment, Packaging Machinery, Electric Cars, Motorcycle, Food Machinery, Marine, Mining Equipment, Agricultural Machinery, Car, Textile Machinery, Garment Machinery, Conveyor|
|Surface Treatment:||Polishing, Polishing|
|Structure:||Roller Chain, Roller Chain|
|Type:||Bush Chain, Bush Chain|
Can mill chains be used in wastewater treatment and sewage systems?
Yes, mill chains can be used in wastewater treatment and sewage systems for various applications. These chains offer specific advantages that make them suitable for such environments, where exposure to corrosive and abrasive materials is common. Here are some key points regarding the use of mill chains in wastewater treatment and sewage systems:
1. Corrosion Resistance: Wastewater and sewage often contain corrosive substances, such as acids and chemicals. Stainless steel mill chains are particularly beneficial in these environments due to their corrosion resistance, which helps to prevent premature wear and elongation of the chain.
2. Abrasion Resistance: Mill chains are designed to handle heavy loads and resist wear and abrasion, making them suitable for applications where wastewater may contain abrasive particles, sediment, or sludge.
3. Reliability: In wastewater treatment and sewage systems, reliability is crucial to maintain smooth operations. Mill chains, when properly selected and maintained, provide reliable performance and minimize downtime.
4. High Strength: Mill chains are capable of handling heavy loads and high-capacity material transfer, making them suitable for wastewater treatment processes that involve moving large volumes of liquid or solid materials.
5. Easy Maintenance: Stainless steel mill chains require minimal maintenance, which is beneficial in wastewater treatment facilities where regular maintenance can be challenging due to the nature of the environment.
6. Resistance to Harsh Chemicals: Wastewater treatment processes often involve the use of various chemicals for treatment and purification. Stainless steel mill chains can withstand exposure to these chemicals without deteriorating or compromising their performance.
7. Extended Service Life: Due to their corrosion and abrasion resistance, mill chains can have a longer service life in wastewater treatment and sewage systems compared to conventional carbon steel chains.
8. Versatility: Mill chains come in various configurations, including standard, double pitch, and heavy-duty options, allowing for versatility in designing wastewater treatment systems to meet specific requirements.
Overall, mill chains, especially those made of stainless steel, are a reliable and durable option for use in wastewater treatment and sewage systems. Their corrosion and abrasion resistance, high strength, and low maintenance make them well-suited for handling the challenging conditions and materials encountered in these applications.
Can mill chains be used in petrochemical processing and refineries?
Yes, mill chains can be used in petrochemical processing and refineries, but the selection of the appropriate chain type is crucial to ensure optimal performance and safety in these demanding environments. In petrochemical processing and refineries, mill chains are often employed in various applications, including material handling, conveying, and elevating tasks.
The key considerations when using mill chains in petrochemical processing and refineries include:
- Corrosion Resistance: Petrochemical environments can be highly corrosive due to exposure to chemicals and moisture. Therefore, selecting mill chains made from corrosion-resistant materials, such as stainless steel or plastic, is essential to prevent premature wear and failure.
- Temperature Resistance: Petrochemical processes often involve high temperatures, so it’s important to choose mill chains that can withstand the specific temperature range of the application without losing their structural integrity or mechanical properties.
- Chemical Compatibility: The mill chains must be chemically compatible with the substances being handled in the petrochemical processes. Compatibility ensures that the chains won’t react with the chemicals, preventing contamination or degradation.
- Load Capacity: Depending on the application, mill chains must be capable of handling the required loads and forces present in the petrochemical processing and refining operations.
- Reliability: In critical processes within petrochemical facilities, reliable mill chains are essential to ensure uninterrupted operation and prevent costly downtime.
- Safety: Safety is of utmost importance in petrochemical processing. Employing mill chains with proper safety features, such as overload protection and anti-jump guides, is vital to minimize the risk of accidents.
Regular maintenance and inspection of the mill chains are also necessary to ensure their continued performance and to detect any signs of wear or damage promptly. Overall, when chosen and used correctly, mill chains can effectively meet the demands of petrochemical processing and refineries, providing a durable and efficient solution for material handling and conveying needs.
What is a mill chain and how is it used in industrial applications?
Mill chains, also known as conveyor chains or industrial chains, are a type of heavy-duty chain used in various industrial applications. They are designed to convey or move materials in a controlled and efficient manner within industrial processes.
These chains typically consist of a series of interconnected links that form a continuous chain loop. Each link is designed to engage with sprockets, which provide the driving force to move the chain and the attached materials.
Mill chains are commonly used in industries such as:
- Steel Production: In steel mills, mill chains are used to transport raw materials, such as iron ore, coal, and limestone, to various processing stations.
- Lumber and Paper Industries: Mill chains are utilized to convey logs, wood chips, and paper rolls in sawmills and paper mills.
- Cement Plants: These chains are used to transport materials like limestone, gypsum, and clinker in cement manufacturing.
- Grain Handling: In grain elevators and agricultural facilities, mill chains are used to move bulk grains and seeds.
- Mining: Mill chains are used in mining operations to transport minerals and ores.
- Automotive Manufacturing: These chains are used in assembly line processes for automotive production.
- Bottling and Packaging: Mill chains are used to move products through bottling and packaging lines.
One of the essential features of mill chains is their robust construction, which allows them to handle heavy loads and endure harsh environments. They are often made from durable materials, such as carbon steel or stainless steel, to resist wear, corrosion, and other forms of damage.
Mill chains play a vital role in streamlining industrial processes, increasing productivity, and ensuring the efficient movement of materials throughout various stages of production. Proper maintenance and lubrication are necessary to extend the life and performance of mill chains in demanding industrial applications.
editor by CX 2023-08-21