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This page illustrates a number of possible arrangements for spark arresters, along with a note of their strengths and weaknesses.
As the needs of each locomotive and owner will vary, there will never be a single solution.
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Type 1: External - Bee Hive - as used on some full size traction engines.
| Pros: | 1) easy to make and cheap
2) easy to fit
3) easy to clean |
| Anti: | a) spoils aesthetics [depends on prototype]
b) collects oil, therefore difficult to clean and will block up readily
c) may produce some back pressure |
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Type 2 - Deflector plate : a tube arrangement fitted in the chimney, with a fixed top. A large slot in each side of the tube deflects the debris sideways and downwards.
| Pros: | 1) very easy to fit and remove
2) protects train passengers
3) minimal cleaning required |
| Anti: | a) doubtful effectiveness - alters where sparks and oil go rather than collecting them
b) looks - not based on any prototype design
c) spoils the overall appearance of the locomotive, and could throw debris and oil onto the track, or bystanders - not recommended |
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Type 3 : Internal screen down stem of blast
| Pros: | 1) not difficult to fit depending on outside shape of petticoat pipe |
| Anti: | a) will very likely affect the blast efficiency
b) will require regular cleaning (from oil clogging). |
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Type 4: Wire mesh at the rear of the smoke-box. Problems with this arrangement, removing the mesh from the back of the smokebox, around the blast pipe. Likely ash would tend to block up very quickly and may even block the tubes.
| Pros: | 1) collects only fire debris
2) does not affect blast configuration |
| Anti: | a) very dependent on smoke box design
b) almost impossible to fit with super heaters
c) fitting through front of firebox not possible
d) difficult to clean insitu and makes tube cleaning impossible.
e) accumulation of ash behind screen difficult to clean out and may block tubes |
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Type 5: cylinder of mesh tapered to base.
| Pros: | 1) collects only fire debris
2) does not affect blast configuration
3) most flexibility in design **
taper will encourage debris to fall off |
| Anti: | a) may need to be shaped to fit around super heaters
b) needs careful manufacture for good fit and easy assembly
c) careful design to ensure adequate area with no loss of draughting. |
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Type 6 - full cylinder of mesh held in a disk base, or by jubillee clip.
| Pros: | 1) collects only fire debris
2) does not affect blast configuration
3) allows maximum depth of mesh |
| Anti: | a) may need to be shaped to fit around (avoid) super heaters
b) needs careful manufacture for a good fit and easy assembly around petticoat flaring
c) careful design [or experiment] to ensure adequate area with no loss of draughting. |
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The above illustrates some possible arrangements for spark arresters; but as the needs of each locomotive will vary, there will never be a single solution.
Please select the next page to conclude this article on spark arresters.
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