Hiscox's Meissner stoker uses a rock shaft to drive a wide plunger that moves charge from beneath a hopper onto a step grate and rocking gate. The calculator measures ideal cycle count and plunger travel.
Plunger-Cycle Calculator
Enter one-way plunger stroke, plunger width, cycles per minute and elapsed time. The calculator counts ideal cycles and travel only; width is shown for geometry and is not converted to delivered mass.
Equation Used
- Every commanded cycle completes one forward and one return stroke.
- The calculation assumes one rock-shaft oscillation produces one plunger cycle.
- Plunger width affects only the drawing; charge volume and mass are not inferred.
- Fuel, combustion, air, grate performance, slip and losses are excluded.
Hiscox's Meissner stoker uses a wide plunger, rock shaft, step grate and rocking gate. This calculator reports cycle count and plunger travel only.
Wide plunger, rock shaft and step grate
Hiscox item 213 shows a wide plunger operated from a rock shaft. The plunger pushes charge from beneath the hopper onto a step grate, where it is worked down an inclined rocking gate.
An oscillating shaft drives the guided plunger through a fixed-length connecting rod. Equal rocker arms and fixed-length links couple the rocking grate sections to the same shaft. The linkage dimensions illustrate the operating principle; they are not dimensions taken from the historical drawing.
Historical mechanism illustration
Use the calculator to estimate ideal plunger cycle count and total travel. Fuel rate, combustion air, grate capacity and controls depend on machine dimensions and operating conditions that are not included here.
Plunger-cycle equations
The factor of two counts the forward and return travel. The calculation uses one rock-shaft oscillation cycle per plunger cycle. Use the actual drive ratio when applying these equations to another machine.
Plunger-cycle example
For a 200 mm one-way stroke, 12 cycles per minute and 60 minutes, the calculator reports 720 cycles, 288 m of total plunger travel, 80 mm/s mean absolute speed and 720 rock-shaft cycles at the assumed 1:1 ratio. The 300 mm plunger width changes the drawing but not these outputs.
What the calculator includes
The calculator follows the wide-plunger and step-grate arrangement shown by Hiscox. It reports ideal cycle count, two-way plunger travel, mean absolute speed and rock-shaft cycles at the stated 1:1 ratio. It does not calculate coal feed, combustion air, boiler load, grate capacity, wear or maintenance intervals.
Meissner stoker questions
Does the calculator predict fuel delivery?
No. It has no charge volume, density or fill model.
Does plunger width change the outputs?
No. Width is illustrated only.
Can the results size air flow or a grate?
No.
Primary historical references
- Gardner D. Hiscox, Mechanical Movements, item 213: Meissner wide plunger, rock shaft, hopper, step grate and inclined rocking gate.
- US820528, Overfeed stoker: shows another overfeed arrangement that uses a feed ram and swinging shovel rather than the Meissner plunger and step grate.
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