technical data Large size conveyor chain Selection
14. How to use chains in special atmospheres
A special atmosphere is one that is cold, hot, humid, dusty or chemically active, as opposed to a clean atmosphere at normal temperature.
The environments in which conveyor chains are used often have a combination of these complex conditions, so the key to ensuring a long chain life is to carefully select the materials that make up the chain.
14.1 Low temperature atmosphere
When using the product in a freezer or in a cold climate, pay particular attention to the following points.
1) Low-temperature brittleness of materials
Generally, materials tend to become brittle and their impact strength decreases at low temperatures, although the degree of this difference varies depending on the material.
Table 13 shows the criteria for usage limits that take this into consideration.
Table 13. Use limit standards for low-temperature brittleness of materials
| Conveyor Chain | Usage limit standard (℃) |
|---|---|
| Conveyor chain DT, DTA, ATA, SSA | -20 |
| Heavy Duty Conveyor Chain AT | -60 |
| Environment-resistant conveyor chain GS/GSA | -70 |
| Environment-resistant conveyor chain SS | -100 |
Note: Please consult us if you wish to use the product at temperatures below -20°C.
2) Poor bending and roller rotation due to freezing
When chains are used in low temperatures, moisture that has seeped into the gaps between the pins and bushes, plates and rollers, and rollers can freeze and form frost, causing problems such as poor chain bending, poor roller rotation and sticking between the chain and rail. This phenomenon can cause overload on the chain and drive unit.
To prevent freezing, it is common to apply a lubricant that will not freeze at operating temperatures to each part of the chain to prevent moisture, frost, etc. from penetrating. Silicone grease is recommended for filling gaps.
14.2 When the atmosphere is at high temperature (400°C or higher)
When the chain is heated by the high-temperature atmosphere or the high-temperature transported goods, the chain strength decreases as the temperature increases.
The limit of high temperature use is determined by the temperature of the chain itself and the materials used.
1) Changes due to high-temperature heating and points to note
- (1) The coefficient of friction is greater than at room temperature
- (2) Welding dissimilar materials can cause thermal fatigue due to differences in thermal expansion coefficients.
- (3) In an atmosphere of 400°C or higher, the clearance should take thermal expansion into consideration.
- (4) Creep rupture
- (5) High temperature brittleness
- (6) Embrittlement due to carbide precipitation
- (7) Repeated thermal shock (cooling, expansion), etc.
2) Lubricating oil
Silicone-based and fluorine-based oils and fats containing graphite or MoS2 have excellent heat resistance.
14.3 In abrasive atmospheres
The key points to note, especially in cases of high wear, are as follows:
- 1) Select a conveyor type that will prevent highly abrasive conveyed materials from falling on the chain. Attach a cover.
- 2) Keep the chain speed as slow as possible.
- 3) Increase the chain size to reduce the bearing pressure between the pin and bush.
- 4) Attach a grease nipple to the pin and grease it.
14.4 Corrosive Atmospheres
If the chain is exposed to corrosive substances
- 1) Chain parts become thin.
- 2) Wear progresses rapidly due to corrosion-induced wear.
- 3) Rust causes poor bending of the chain and poor rotation of the rollers.
- 4) In acidic or alkaline environments, problems such as stress corrosion and intergranular corrosion can occur, so particular care is required.
Table 14 shows the corrosion resistance of chain materials in various solvents, so please use it as reference for your consideration.
Parts GS Series or GSA Series (stainless steel 400 series) may rust depending on the environment in which they are used.
If there is a risk of stress corrosion, we can manufacture a product with stress corrosion prevention specifications, so please let us know.
Regarding corrosion, please contact us and let us know the materials used around the chain (e.g. rails, components, tanks, etc.).
Table 14. Corrosion resistance to various solvents
When selecting a chain, check the table below to see if the material has sufficient corrosion resistance.
Please note that this table indicates the degree of material properties at 20°C, and does not indicate the degree of guarantee.
When actually using the product, please consider the humidity, usage conditions, etc.
15. Beautiful specifications
| classification | Applicable | Degree of beauty | Purpose | Rust prevention oil | packing |
|---|---|---|---|---|---|
| 1st grade | All parts are stainless steel (SS Series) | There is no adhesion (oil, dirt, black scale), burrs or burrs. Wipe with a white cloth to remove dirt. |
For chemicals or raw materials May come into direct contact chain |
none | Wrapped in heavy wrapping paper and vinyl sheet, then boxed |
| 2nd class | All parts stainless steel (GS Series or a combination of GS Series and SS Series) |
No adhesions (oil, dirt, black scale), burrs or burrs. | Wrapped in heavy wrapping paper and vinyl sheet, then boxed Note) 1. Volatile rust inhibitor is packaged at the same time. |
||
| 3rd class | Some or all of the parts are made of ordinary materials | After assembling the chain, degreasing and cleaning are performed. No oil or dirt buildup, but black scale remains. |
Note)
- 1. Conveyor chains are subject to oil from the manufacturing process. We will accommodate requests other than the above aesthetic specifications whenever possible, so please contact us.
- 2. The surface of the material is basically black (coated), but depending on the product type, reddish scale may be present. Please contact us if you plan to store the product for a long period of time.
