This historical stoneware filter has an upper water jar and a lower storage jar. The illustrated path passes through a sponge-filled opening, charcoal and a porous plate before dripping into the lower jar. Enter an observed drip rate to estimate batch time, then compare several batches with the available storage capacity.
Stoneware Filter Interactive Calculator
Enter a measured drip rate and jar volumes for the documented two-jar household filter. The calculator reports batch time and lower-jar storage balance only.
Equation Used
- Entered drip rate is an observed average.
- No evaporation or retained liquid is deducted.
- No contaminant removal, microbiological safety or potable-water suitability is predicted.
The upper jar feeds a sponge-filled opening, charcoal bed and porous plate. Water then drips through the open outlet into the lower storage jar.
Following the water path
The cross-section follows Hiscox movement 583. Water in the upper vessel reaches a sponge-filled opening, passes through a charcoal bed and porous stone plate, and leaves through an open outlet into a separate lower vessel.
Main parts
- Upper jar: holds the entered charge of water.
- Sponge-filled opening: lies at the entrance to the illustrated media path.
- Charcoal bed and porous plate: form the intermediate layers shown in section.
- Open outlet: delivers drops to the lower vessel.
- Lower jar: stores the accumulated volume.
The animation’s lower water level is a schematic storage indicator. It is not a calibrated height-to-volume scale for the tapered jar. The drip-rate input is an observed average; the calculator does not derive it from pore size or water head.
What the household-filter example shows
The two jars separate the charged water from the collected water. This makes the arrangement useful for illustrating the difference between flow rate, time per batch and available storage.
The page describes a historical flow path. It does not establish removal of a particular contaminant, microbiological safety or suitability for drinking water. Those results cannot be inferred from jar capacity, an observed drip rate or the presence of charcoal.
Batch time and storage balance
For an upper-jar charge V and average drip rate q, time per batch is t = V/q. For n batches, total volume is nV. Potential overflow is max(0, nV − C), where C is lower-jar capacity.
With volumes in litres and q in litres per hour, t is in hours. Storage fill is 100 × min(nV, C)/C, so it stops at 100% while overflow is reported separately.
The calculation assumes an initially empty lower jar, no water withdrawn during collection, and no evaporation or retained liquid. Actual flow may vary as head and media condition change.
Worked example: three batches into one storage jar
For an illustrative upper charge of 4 L, measured average drip rate of 2 L/h, lower capacity of 10 L and three batches:
- Time per batch = 4/2 = 2 hours.
- Total batch volume = 3 × 4 = 12 L.
- The lower jar reaches 100% storage fill, with 12 − 10 = 2 L potential overflow if no water is removed.
Two batches would instead total 8 L and fill 80% of the jar. These results concern quantities and time only; neither case says how clean the collected water is.
Keeping flow and storage questions separate
| Question | What is needed |
|---|---|
| How long will a batch take? | Charge volume and an applicable observed average drip rate. |
| Will the lower jar overflow? | Total incoming volume, initial contents, withdrawals and capacity. |
| What substances are removed? | Evidence of performance for the actual media, water and operating conditions. |
This calculator handles the first question and a simplified empty-jar version of the second. It does not compare pressure-filter candles or provide media-cleaning procedures.
Frequently asked questions
Is this an industrial candle filter?
No. The illustrated arrangement has an upper jar, a sponge-filled opening, charcoal, a porous plate and a lower storage jar. Its calculator is a batch-time and storage balance.
How is the drip rate determined?
You enter an observed average rate in litres per hour. The calculator does not infer flow from media properties, pore size or pressure.
Why does storage fill stop at 100%?
The lower jar cannot store more than its entered capacity. Additional calculated volume appears as potential overflow.
Does the lower jar start empty?
Yes. The balance assumes no initial contents and no withdrawals while the selected batches collect.
Does changing the number of batches change time per batch?
No. Time per batch is upper-jar volume divided by drip rate. Batch count changes total volume, storage fill and potential overflow.
Does the result mean the water is safe to drink?
No. It calculates only time and volume. It does not predict contaminant removal, microbiological safety or potable-water suitability.
References
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