Steam Engine Reviews/Arrowhead Bump Valve Summary
Steam Engine Reviews
The so-called Arrowhead Bump Valve engine design has been reviewed by several people at the current time (7/20/11). This page summarizes the design problems and provides suggestions on how to deal with them.
- Horizontal layout promotes wear, jamming, etc.
- Water can condensing in the engine leading to a blow-out.
- Placement of exhaust vent means compressing air in the cylinder and losing work.
- Steam is admitted before top dead center, losing some work.
- Valves must seat and create a seal against steam.
- Valves are heavy and slow to react.
- Valves take a beating from bump pins.
- Valve opening and timing is critical - difficult to adjust.
- Cylinder liner is expensive.
- Cylinder end needs holes to let in (and out) air.
- Piston rings are expensive.
- Oiler is expensive.
- Piston head is heavy, moving it loses work.
- Piston head has no heat shield.
- Bump pins may vibrate out of their holes.
- Oil mixes with steam and causes pollution.
- Crankshaft is built up of parts that must be precisely aligned or vibration results.
- Engine is hot - no shields for safety.
- Crankshaft is open - safety hazard.