This document summarizes improvements made to the production process of ceramic water filters. It describes optimizations to raw material selection and inspection, mixing techniques, drying methods, firing profiles, and kiln design. These changes were aimed at reducing cracking during production and increasing yield. Key results included the production yield increasing from 55% to over 70% and then 86% after implementing a new firing profile and kiln layout that improved temperature control during firing.

1. Spout of Water
Wirat Lerdprom
Technical Consultant for Ceramics at Lucideon
Former PCSA, American Ceramics Society

2. PurifaayaTM ceramic water filter
2
https://spouts.org/purifaaya/
How does PurifaayaTM work?

3. Production process
3
Pressing
Drying
Firing
Flow rate control
Grinding Dry Mixing Wet MixingRaw mat’l Sieving
Packaging

4. Raw materials stock yard
4

5. Raw materials
5
Black clay Yellow clay
Saw dust Grog

6. Dry grinding
6

7. Sieving
7
Black clay
60#
Yellow clay
Saw dust
Grog
Dry Mixer
80#
(recommended)

8. Wet mixing
8
No water content
controlled

9. Pressing
9

10. Drying (2 days in plastic bags)
10
A plastic bag used
1. Preventing the mixture
to stick to the mould.
2. Slow down of drying
rate.

11. Drying (4 days half-opened plastic bags)
11

12. Drying (2 weeks in drying barn)
12

13. Firing
13

14. Quality control
14

15. Problems
15
Pressing
Drying
Firing
Flow rate control
Grinding Dry Mixing Wet MixingRaw mat’l Sieving
Packaging
Crack Crack Crack

16. 16
> 40 wt. %
of free quartz
in each clays
Clay
Free quartz
Gravel
Raw materials inspection

17. 17
A porous ceramic body
used as plaster mould
Clay
(high plasticity)
Free quartz
(low plasticity)
Raw materials inspection

18. Clay plasticity testing
18
In-house testing procedure Testing instrument

19. Drying
19

20. Drying
20
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
50.0 60.0 70.0 80.0 90.0 100.0
Moisture content (%)
Dryingrate(dM/dT)(g/hr)
SPOUTS Data
Wet pots
Critical
moisture content
Dry pots
Drying
Shrinkage

21. Drying process improvement
21
Sunlight
Natural air-circulation
system
Humidity
Temperature
100% closed module 70% closed module 100% open module
Humidity
Temperature
(a.u.)(a.u.)
Existing system
Developed system
M-1 M-2 M-3
M-2&3
Coldair
Hot air

22. New firing profile
22
New Firing Profile
Existing Firing Profile
1
2
3
4
1. Physically boned water burnout
2. Chemically bounded water burnout
3. Quartz inversion (-)
4. Carbonate, sulphate, organic burnout
Production yield increased from 55%
to
70% (14 Jan 2017)
86% (21 Jan 2017)

23. Kiln layout improvement
23
900°C
250°C
TC-Top
TC-Bottom
Fire wood in
TC-Top
TC-Bottom
Fire wood in
Existing system Developed system
Flue gas Flue gas

24. Summary
• Raw materials daily inspection.
• Dry and wet mixing improvement
• 80# recommended
• Clay plasticity testing and standard setup.
• Drying process
• Drying profile and drying rate
• Green house drier design
• Firing
• New firing profile recommended
• New kiln design
• Results
• Production yield increased to 86% (from 50%)
24

25. Thanks for your attention
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