WAYNE'S WATER FILTER
PROJECT
ABSTRACT.
After considering various alternatives and options, a filter for filtering
water to make it potable is presented. It consists of an optional prefilter, a
Katadyn ceramic filter, and an optional activated carbon post filter. There are
several options for forcing water thru the filters. All are based on the
principle that a small pressure for a long time is more efficient than a high
pressure for a short time. These include elevating a tank to provide pressure
due to gravity, useing water that is already elevated, amplifying that pressure
with a hydraulic ram, and useing an electric pump.
I have been exploring several low cost
options for purifying drinking water. The lowest initial cost and least energy
efficient method is to heat the water to boiling. Heating it to 149 degrees F
for 6 minutes (pasteurization) kills the major pathogenic organisims including
virus. Energy requirements can be
reduced to a reasonable level if a very good heat exchanger is used to heat the
raw water with the pasteurized water. Surface water should be prefiltered with
the 1 micron prefilter discussed later and will benifit from the activated
carbon filter discussed later. The main
problem with this is that a thermostatic valve is required to regulate the
water flow. Years of experience with these valves clearly shows that affordable
commercially available valves are far from hippy proof. A write up on this
method appears in Home Power magazine #52. If you wish to construct such a
device, please consult with me regarding the heat exchanger and valve. There are also some possibilitys with
batch processing with a combination of chlorine and hydrogen peroxide, again
not very hippy proof. Contact me if you want more info.
I believe that filtration will be the most
generally useful method in the "Rainbow environment". The systems I
present below are intended to make filtering affordable to the average and
large kitchen. Further investigation revealed several general principles:
Contaminants in water vary so widely that definitive answers to the question of
what filters are best or their expected life cannot be given. A completely
hippy proof system is not possable. Hippy proof withdrawl of water is possable,
installation is close, but cleaning the filter I recommend is not. This does
not mean that unsafe water may be
produced, but
that poor cleaning practices will result in poor filter life or low filtration
rates. Anyone cleaning the filter should read the section on cleaning. Some
have ruined a good filter by totally disregarding the cleaning instructions.
The best system configuration will vary greatly with the designed capacity and
local conditions. It is intended to be kitchen sized as a minimum but is
suitable for an individual or to to provide over 2 GPM continuously when used
with hydraulic ram, electric or other pump. It is easy to setup and intended
for a camp of short duration such as a rainbow gathering but not for a group
that is on the moove. I can provide
more detailed drawings by US mail on request, but unless you have the parts and
facilitys on hand, you will probably want to buy atleast part of this ready
made. My mailing address is Wayne Robey, 215 S. 6th St., Lafayette, Indiana
47901.
PARTICULATE FILTER SELECTION
As the filter becomes finer, the flow rate
decreases rapidly. Removal of most virus by filtration is not practical, if
this capacity is desired, it would be desirable to filter water thru a good
prefilter into a storage tank, treat the water with iodine or chlorine, and
after sitting long enough pass it thru a high capacity activated carbon filter.
If the carbon filter is not cleanable, it should have a suitable prefilter to
keep it from cloging. In the North American wilderness, virus is not generaly
considered to be a problem but a large gathering is not wilderness. The details
of this process are not included in this paper. For complete removal of
microorganisms (I take virus to be a particle not an organism.) the generally
accepted requirement is .2 micron though .4 micron works nearly as well,
(E-coli is one organism that could occasionaly slip through a .4 micron
membrane filter but that is not disatrous.) while cryptosporidia and giardia
vary, some believe that they are readily removed with a 2 micron filter but as
protozoa divide, a finer filter is required. One thing to watch here is that
some .4 micron nominal filters will pass a signifigant ammount of 10 micron
particles and are only useful as prefilters. In general a non cleanable filter
will pass more water initially but have a much shorter life than one that can
be cleaned many times by removing the contaminated surface. Water quality from
a questionable or contaminated source varys greatly and cannot be predicted
with any confidence. Specifications for
typical or maximum life in terms of gallons of water filtered are meaningless.
Since there is no standard water for rating filters and particle size
distributions vary greatly, these advertised lives cannot eaven be used
reliably to compare filters. I have seen the cleaning frequency change by a
factor of 5 from the same source over the period of a week. Water from the
Wabash river reduced the flow of a Katadyn 1040 filter to .6 of the inital
value after 2 gallons, at the 1996 North American gathering 160 gallons of
spring water was required when useing a 1 micron prefilter. Deep well water
will usually require more than this, while pure water will never clog the
filter. At the 1998 Ocala gathering, fine particulates penitrated deeply into
the Katadyn ceramic. For these reasons, a great deal of surplus filter life
should be available. For general use, I settled on three of the Katadyn ceramic
filters, the #4 (article 1040), the LP-K700 (article 1700) and the CERADYN
(article 20743). All have a nominal pore size of .2 microns and are well
established as reliably producing safe water. The main differences between them
are shown below. All have advantages and disadvantages. The main advantage of
the 1700 is the high thru-put to size ratio but has a much shorter life. A good
fiting housing can be easily made from readily available parts. The 1040
provides long
life under favorable conditions, best ruggedness due to the metal construction
and the tension maintained by the metal on the ceramic and better filtration of
particles smaller than .2 microns. The 20743 combines the short life of the
1700 with the size of the 1040 for the highest thru-put. The flow rate as a
function of pressure is linear over the useful range. The new flow rate is not
fully restored by light cleaning due to the fact that the ceramic contains some
large pores which increase the inital effective surface. In addition, clay,
smoke, carbon black, and possibly other inanimate particles exist as a continuous
distribution of sizes over the .05 to .3 micron range. Virus also exists in
this range but clay is the most common problem. Some of these will penitrate
the ceramic to great depths. This is a greater problem with surface water than
spring water and much worse if the water is mudy due to a recient rain than if
it is clear. This should be kept in mind when selecting a gathering site. This
has more effect on the #1040 than on the #1700 because of it's greater life. On
the other hand, lake water filtered thru a new #1700 at the 1998 Ocala
gathering was not as pleasing as that filtered thru the #1040 due to the
greater ceramic depth of the #1040. If the water has been favorable, the #1040
filter approaches the performance of the #1700 as it ages. The chart below
shows the conversion between clean filter, instantaneous, and average flow. The
cleaning point is the instantanious flow when the filter is taken down for
cleaning. The quanity filtered is the water filtered in arbitrary units before
the filter needs to be cleaned again. (The conversion from these arbitrary
units to gallons depends on the water quality.) Since each cleaning removes
about the same ammount of filter ceramic, this number is inversly proportional
to filter life. It appears to me that for system sizing, it is wise to plan on
cleaning the 1040 filter when the flow is half the initial flow but in use, it
is wise to clean less frequently when there is no shortage of filtered water.
Type OD
Ceramic OD removable Length
Flow rate List
new end life ceramic when new Price
1040 2.175"
1.975 1.50 11.7 cu in
11.52 18.2 gpd/psi $90
1700 1.813"
1.605 1.50 2.8 cu in
10.68 29.1 gpd/psi $75
20743
2.163" 1.975 1.87 10.68
50 gpd/psi $75
item 1040 (flow in gallons per day @ 1 psi) item 1700
quanity cleaning average Initial * quanity
cleaning average Initial
filtered point
flow flow *
filtered point flow
flow
.6962 12.8
15.69 18.2 * .4588
20.5 24.58 29
1.000 9.1
13.85 18.2 *
.7632 14.5 21.07
29
1.156 6.4
12.43 18.2 *
.9734 10.2 18.23
29
1.249 4.5
11.42 18.2 *
1.110 7.25 16.02
29
item 20743 (flow in gallons per day @ 1 psi) item
quanity cleaning average Initial * quanity
cleaning average Initial
filtered point
flow flow *
filtered point flow
flow
.3654 35.31
42.1 50.0
.6444 25.11
35.75 50.0
.8637 17.63
30.41 50.0
1.000 13.22
26.80 50.0
I have
developed filter housings for the Katadyn elements which are made from standard
plumbing fitings as far as possable and are described below. The holder for the
1700 is based on 2" schedule 40 PVC parts, uses a friction fiting test
plug and is the easyest of the three to make. The filter is supported on both
ends for ruggedness. The best holder for the 1040 is based on the uncommon 2
1/2" schedule 40 fittings. I have been unable to find a suitable 2
1/2" test plug so it has to be made. An entirely different design which
requires a lathe but allows the housing to be opened at the top has also been
developed. Cleaning the filter is quickest with this design. The filter element
is supported on both ends for ruggedness. The third holder can be used for
either element and is based on 3" thin wall PVC parts. It is not much
bigger than the second, uses much less PVC, but is not rugged. There is no
pressure rating on the parts, some of which seem to be poorly made. This would
be a good choice for home use at pressures not exceeding 5 PSI. This minimal
housing supports the element as well as any of Katadyn's but I suggest that
some means be provided to support the bottom of the filter elements during
transport. A concentric prefilter could be built into this housing (probably
useing polyester felt) but would be clumsy due to the frequency of cleaning the
inner filter. This simple easy to make housing plus easy to reach input and
output reservoirs provides much more water than the Katadyn siphon filter at a
nearly equal price and much more than the drip filter at a much lower price.
All of these holders require a special nut (for the 1040 element) or special
tube connector (for any filter element) which I can supply. The friction fit
test plug is used rather than a pipe thread fitting because I do not believe
the pipe thread would have the durability required for the hundreds of
cleanings required over the life of the housing. To keep any installation of
more than one element managable, it is important to rigidly mount each filter
holder as well an the input and output manifolds. Additional detailed
information as well as the finished holders are available. I believe that
obtaining the hardware from me is more practical than making your own unless
you prefer a different design or prefer to use different materials.
PREFILTERS
The prefilter
is useful when the main filter will encounter significant wear. When the water
is clean or the use light, it is usually not worth the trouble. While water varies greatly, my experience is
that a 5 micron wound polypropylene filter will cut the cleanings of the
Katadyn filter in half while a 1 micron pleated filter will cut the cleanings
to 1/4 of that required without the prefilter. They are normally economical in
that they do not clog too fast but the specifics vary greatly with the water.
While all prefilters will always be cost effective with the 1700 and 20743
filters, it is less clear for the 1040. When cost savings with the 1040 is the
prime concern, the 5 micron wound element can not be excluded. It is also more
readily available. The following
example related to me from their use in Ocala lakes: With a 1 micron filter, 3
Katadyn #1040 elements operating in parallel will need to be cleaned after 40
minutes of use, without a prefilter, they will need to be cleaned after 10
minutes. One prefilter lasts about 1 day. If cleaning the 3 Katadyn filters
takes 30 minutes and the system is used 16 hours a day, it will run for 14
cycles or 9.3 hours per day with the prefilter or 24 cycles or 4 hours without
the prefilter. First notice the 130% improvement in running time and total
water output with the prefilter. (This could be increased to 16 hours running
time or another 72% by adding a fourth Katadyn element, and removing them one
at a time for cleaning. Then one element would be down for cleaning at all
times but the system would always be up.) Secondly, notice that one 1 micron
prefilter lasts for 42 cleanings of a Katadyn #1040 element. During this time
it saves 3*42= 126 cleanings. If the life of the Katadyn #1040 is 300
cleanings, it saved .42 of a #1040 element. The retail price of the 1 micron element
is $5, and the #1040 is $90, so each of these prefilters saves $33 in system
cost. Since I am not sure of the accuracy of the above lifetimes, the actual
savings could be as small as $15. In order to avoid making a special housing
for these, I have used a the common houshold filter holders with the input and
output connections idenical for backwashing. To prolong prefilter life,
installations which use more than 2 ceramic filters in paralell should consider
useing prefilters in paralell to prolong their life.
WATER SOURCE
SELECTION
Since the
Katadyn ceramic does not remove most virus or chemicals, these should be
avoided or treated by other means. While the cleanist water avilable should be
used, two things should be kept in mind. Clear water can be loaded with
bacteria and protozoa which quickly clog the filter. While turbidity is not a
good indicatior, clay introduced by runoff is to be avioded whre possable
because the size distribution can allow it to deeply penitrate the ceramic as
explained above.
CHEMICAL REMOVAL THOUGHTS AND
OPTIONS
It may also
be desirable to remove various chemicals but it may not be worth the trouble if
precautions are taken in selecting the water source. Activated carbon and selective
ion exchange resins can do this but have a variety of limitations so it is
important to understand what you want to remove. In addition, as the filters
age they give no indication of their effeciveness. Overall, this cannot be
hippy proof. The most common problem with surface water will indicated by poor
taste due to various metabolites. This will also be true for water that has
been stored for a long time. This is also the easyest to detect and remove but
minerals can also have an undesirable taste and will not be removed by
activated carbon. Agricultrual runnoff is a potential source of herbacides and
pestacides as well as nitrates, (and clay which is another good reason to avoid
it). Toxic metals can result from mineing or other industrial activity.
Chemical contamination can result from small scale activity and be unsuspected.
In some areas arsenic occurs naturally. The first thing to realize is that as
these filters become saturated with a specific contaminant, they let more and
more pass thru. If you can't detect it and don't know how much is in the feed
water, you can't be certain that any filter is doing it's job. While free
chlorine and many odors are easily detected and removed, many organic chemicals
require varying degrees of long contact with high activity activated carbon and
are not easily detected. As the system flow goes down contact time (and
effectiveness of the activated carbon) increased. This is another advantage
this system has over those that are pumped to a high pressure by an impatient
operator to get high flow for a short time. To reduce growth of organisms in
the filter, organic particles must be excluded by placing this after the
bacterial particle filter, or it must be cleaned frequently. One activated
carbon filter worthy of consideration because it combines small size and
unusually low flow resistance with very small uniform pore size and high
capacity is a polyolefin bonded powdered activated carbon briquette with a
surface area of 2,200,000 sq ft and a pressure drop of .9 PSI at 1 GPM sold by
Cole-Parmer as cat # E-01508-93 for $26. The Anetek CDC-10 is an alternative
(1.3 PSI @ 1 GPM). An alternate approach adds the ability to remove some
fluoride, lead, cadnium, mercury, and arsenic with hydroxyapatite charcoal. The
granular blend, called R1022, is a more general purpose activated carbon and
can be cleaned so it can be used as the first prefilter but it requires more
attention than the above briquette. Without reactivation, it's life is less
than the briquette. It is available in 80 cubic inch packages from The Rockland
Corp. as stock number 8111 for $18.20. Each package should be able to treat 1/4
GPM. See the section on useing this media. I think everyone useing city water
should have this at home since it has good removal propertys and good life at
no increase in price.
Selective ion exchange resins are useful
to remove metals such as lead, cadnium and mercury which may be introduced by
mining or pesticide use. One problem with these is that they have a poor shelf
life, requiring annual replacement.Catalysts are available without this problem
but they are expensive. Another problem
is that they can support growth of microorganisms. This makes these materials
most suitable for applications requireing small ammounts of water regularly
where a known problem exists. If you want to pursue this, here are two sources:
(1) Western Water International manufactures
Aqua Space Compound filters useing "patented, certified NASA
technology". 7715 Penn Belt Dr., Forestville, MD 20747 301-568-0200
(2) Seychelle Environmental Technologies,
Inc. Seychelle water filtration products are the most tested products in the
world using EPA and ANSI/NSF protocols.
Their primary goal is to make water safe to drink that is contaminated
from suspended pollutants, microbiological, toxic chemicals from industry and
agriculture, heavy metals such as lead, copper, mercury, and radiological
contaminants. CONTACT:
970-920-6500, 714-361-6655, or
email:icd@rof.net
PUMPS
Since the energy required to filter water
is proportional to the pressure, it is desirable to use a low pressure for a
long time rather than a high pressure for a short time. I can think of three
reasonable ways of producing moderate pressure for a long time: (1)
Continuously operated pump powered by motor, human or other power source. (2)
Pressure developed by gravity from water stored above the filter outlet. (3)
Gravity developed pressure amplified by a hydraulic ram. The first case is
great if you have electricity or the filtration system is large enough to keep
a person pumping continuously. A hand operated piston force pump is efficient
and easy to use but is not commercially available. Would someone like to make
some? For an electric pump, a diaphragm pump operating near it's maximum
pressure is efficient and reliable. The two that seem the most suitable are
made by Flojet and are now sold by J.C. Whitney. Stock # 81JZ4553W costs $39.95
and is dvertized as pumping 1.1 gpm @ 35 psi while useing 3.5 amps @ 12 volts.
Stock # 72JZ8421A costs $49.95 and is advertized as pumping 3.3 gpm @ 35 psi
while useing 7.0 amps @ 12 volts and could be suitable at 6 volts pumping 1.6
gpm. J. C. Whitney is not known for accuracy and I have not checked these specs.
The best small diaphragm pump is the Shurflo 8009-541-236 (COST ~$80) which is
a good match for 2 #1040 elements when operated at 12 volts. Specs are .75 GPM
@ 30 PSI & 2.8A, 5000 Hr brush life; .65 GPM @ 50PSI & 3.5A; 60 PSI
max. In the second case, if the water is naturally available at the desired
height, connecting a pipe to it is all that is needed but this will usually be
the case only when small ammounts of water are needed or when the site is
chosen to suit the water source. When only small ammounts of water are needed
it can be carried up to an elevated reservoir and allowed to flow back to the
filter by gravity, pumped up by hand if you have a suitable pump, or a
reservoir such as a 5 gallon bucket or dromedary bag can be hung from a tree by
means of a pully and rope, the water poured in at ground level and hoisted to
the desired height. I don't like this solution because I am worried that
someone will drop the bucket. For
example if a height difference between the middle of the input resivour and top
of the receiving resivour is only 10 feet and a single 1040 filter is used with
the suggested cleaning schedule and a 20% initial loss of capacity is assumed,
10*.433*13.85*(1-.2)= 48 gallons per day or 2 gal/hour could be produced. If
the bucket is used, the filters and tubing can be stored in it. Whenever a
resivour that may run dry is used, atleast one of the filters should have an
air vent to remove the air in the lines when it is filled.
The third solution, a hydraulic ram, is
very nice for taking water from a mountain spring or stream or spring but needs
to be adapted to the site, requires some care in installation and an abundant
source (which is not unusual). The major components are reverse flow input
screen, (a 20 - 30 mesh screen seems sufficient to keep the valves working
smoothly), supply tube if needed, stand pipe if input tube is used, rigid drive
pipe , overflow valve, check valve and air tank to cushion the output. While I
do not have detailed data and have not done any testing, it is reasonable to
expect a cheap but
well
installed hydraulic ram to increase the total head by 6 to 8 times the head
seen by the ram with an efficiency of 50%, greatly reducing the number of
filter elements required. For example a 2" ram set for maximum production
and having a 10 foot drop from a 30 gpm source thru a 40 foot drive pipe could
deliver 2.3 gpm or 3300 gpd at 30 psi (at the pump output) which is sufficient
for distribution to a small network or atleast 6 1040 elements in paralell. A
single 1" ram useing 4.5 gpm under the same conditions would produce about
420 gpd useing a single #4 filter under reasonable operating conditions (280
gallons for a 16 hour day). Here are some design ideas for these pumps: The
supply tube and stand pipe should be as large as practical inorder to deliver
the available head to the pump, the drive pipe length should be 3 to 6 times
the head. For input flows near the minimum, the drive pipe should be near the
maximum to store more energy in the pipe, for flows near the maximum the drive
pipe should be short to reduce frictional losses. The drive pipe must be rigid, the ideal material for the drive
pipe is steel but it is most commonly schedule
40 PVC. Some have thought that PVC should be avoided due to the environmental
impact of producing and disposing of it. I think this is well founded but the
alternatives must be considered. A PVC drive pipe would be the largest use of
PVC by a large measure but the alternatives are steel or a radially glass
reinforced plastic. The overflow and check valves are somewhat matched because
they must work together. The trip point on the overflow valve (and resulting
pump output) can be adjusted by adding or removing weight from the poppet. The
check valve should have an opening back pressure of around .5 psi. Efficent
operation requires the pump to be rigidly mounted. Clamping the check valve
outlet to a bracket which is mounted to a couple of large rocks or stakes would
work. There are several choices for the local storage tank which must be
closely coupled to the check valve. As the number of filter elements being fed
increases, the minimum size of this tank increases. In all cases a vertical
4" pipe of suitable length can be used. It needs a port on top to inject
air (a tire valve and bycycle pump is good). Since air is disolved in the
pressureized water, occasional air additions will be required. This can be
avoided by installing a flexable bladder in the tank. A suitably sized
innertube could be put into the tank. If used, it must be folded, producing
stress points. To prevent problems a large tube with a small enough ammount of
air to prevent excess stress at the folds is required. For short term use this
is probably not worthwhile but for a permanent instalation it is a real convenience.
For pumps driving 1 - 2 filter elements, a tank can be made from a 2" pipe
the bladder designed for the purpose availavle for $24 from the Ram Co. can be
used. The specialized parts shown below are available from the Ram Co., 247
Liama Lane, Lowesville, VA 22967, 800-227-8511. The PVC check valve below may
work better than the brass one, the poppet tees are overpriced and available
locally. The maximum fall into the pump is 15' and the maximum practical lift
above the pump outlet is 11 times the input fall.
SIZE FLOW
RANGE CHECK VALVE WASTE VALVE
GPM PVC Brass housing cap poppet
1" 1-5
RP10LVC $18.88 $19.75 RP10WVH
$10.65 RP10WVC $5.46 RP10PF $11.71
1.5"
2-10 RP15LVC $23.54 $27.55 RP15WVH $13.12 RP15WVC $6.59 RP15PPA $18.63
2" 3-30
RP20LVC $31.58 $35.50 RP20WVC
$15.30 RP20WVC $7.70 RP20PPA $18.63
size complete
pump The complete pump prices may have
changed. Also it is not
1" RP10000 $108 certain what air tank is used. The tanks with the Ram Co.
1.5"
RP15000 $139 bladder are too small for
systems using more than 2 filter
2" RP20000 $175 elements and are a bit questionable for the 2 element case.
SIZING EXAMPLE
First decide
how much water you want. Lets say you want 50 gallons over 12 hours or perhaps
in a 24 hour day but only attended for 12 hours, which is reasonable for a
medium kitchen without many neighbors. Now lets say you want long term life for
the filter in any condition rather than high immediate output. (You could
rework this for good output with clean water input.) My asumption means that
you want to use the #1040 element. If you look at my chart or table, you see
that if you clean the filter when the flow reaches half the new clean filter
value and allow for another 20% loss as explained in the article, the minimum
instantanious flow will be 3.7 gallons/12 hr day at 1 psi or 5.6 gallons
averaged over a cleaning cycle. If the water is clean and the pressure low, the
time between cleanings will be long so the 3.7 gallons is used, realizing that
you will usally have more. Then you can guarantee the 50 gallons from a single
#1040 element if the pressure is 13.5 psi which you can get from a 31 foot
fall. This is reaching the practical limit of what a manually fed system could
achieve so you may want to consider the options:
1. Are you
comfortable with this fall requirement. The answer depends on
who is useing it and the terrain.
2. Require
less peek water production, you always have the option of
cleaning the filter early to meet the
occasional peek demand.
3. Change to
a #1700 element and get the same output with a 20 foot fall.
4. Put 2
#1040 elements in parallel and get the same output with 15.5' fall.
5. By useing
a large receiving tank (in this example
32 gallons is
sufficient) and providing continuous input
from tank or spring, the
operating time is increased to 24 hrs/day
and peak demands are leveled out.
Then the average flow in my table can be
used with confidence provided the
filter does not require cleaning overnight.
Then the 50 gallons per day is
obtained with a head of 2.3*50/13.85/.8=
10.3 feet which is three times
better
than the initial design above. It is also much more convenient to
mannage one large tank than many 5 gallon
buckets (though you could put a
few buckets together - in series for the
output or in paralell for the
input).
CLEANING THE
FILTERS
The sole
advantage of a cleanable filter is longer life and reduced operating cost.
Wastful cleaning will eleminate this advantage. Katadyn supplies a cleaning
tool they call a brush but is realy a rigid (curved to fit the filter) very
course abrasive which will take off a large ammount of ceramic. If this tool is
used, the advantage of a cleanable filter is largely lost. I do not know why
they have provided this tool for these filter elements, but the approaches they
used in some versions of their pocket filter are much better. I estimate an
increase of life of five times or more when using the method I describe here as
compared to the Katadyn "brush". (I have used water pressures of 30
PSI or less in my work while the Katadyn KFT filter can operate as high as 112
PSI which might drive the contamination slightly deeper, so my method could
require modification when used with the KFT filters under some water
conditions. Some users report that my method has worked well on there KFT.) I
estimate 75 cleanings for the LPK1700 and 300 for the #1040 element when Katadyn's
recommended end of life point is used, but this will vary somewhat depending on
the nature of the contamination.
The first problem is to know when to clean
the ceramic filter. With a continuously pressurized or gravity powered system
never clean the filter if you are producing sufficient water. If you are not,
measure the flow and compare it to the flow graph. One approach is to match the
measured flow to the instantanious flow on the graph and read the average flow.
If these numbers are lower than you would like, clean the filter. Ceramic
filters in the home made bottom opening housings are best cleaned by
disconnecting the outlet tube, inserting the protective plug to maintain the
cleanliness of the element's
interior,
remove it from the housing, install the protective cap, IMMERSE the element in
water and clean. Filters in 2.5" housings need not be dismounted for
cleaning. If the element is not discolored, if it is shiny, or if it is slimy
the first step is to brush it with a bristle brush. The bristles should be
similar to those in a medium softness flat bottomed tooth brush or a very short
bristled paint brush. This is to remove the surface slime. If it does not
remove the slime it is too soft and if it removes a noticable ammount of ceramic,
it is too stiff. Do not use a stiff scrub brush because it will gouge the soft
ceramic. If a suitable brush is not available, a fine nylon scouring pad with
little abrasive may be used. See the parts list below. In every case, GENTLY
brush the ceramic as uniformly as possable with an abrasive pad. The common
Scotch Brite abrasive pads used for cleaning kitchenware will do but Niagra
light duty scouring pads are easyer to use for in some cases because they are
less abrasive. If there is a dark deposit on the filter, brush it until the
easily removed discoloration is removed. If the surface is not darkly colored
it is probably covered with slimy microbes. In this case it is hard to know how
much cleaning to do. There is no point to an incomplete cleaning but excessive
cleaning is a complete waste of the ceramic, so start with slight cleaning with
the abrasive. The best indication of the ammount of ceramic removed during
cleaning is the color of the wash water. The best check on the quality of the
cleaning is the flow rate after the element is reinstalled. Make the
measurement after the filter has passed 1 gallon of water to insure that the
air has been purged. If the flow is less than expected, clean more throughly
next time to se if that is helpful. Deep contamination will reduce the flow and
not be removed by normal cleaning, so if a little more cleaning has no effect
on flow, take that as the clean filter value for future reference. To
reinstall, rinse the neck of the element, remove the protective cap, insert the
element in the housing, rinse the neck, install the nut or tube fitting on the
vilter element (IMPORTANT - TIGHTEN THE NUT OR CAP, DON'T TWIST THE FILTER
ELEMENT with much force. The ceramic is not very strong.) remove the protective
plug, purge the air from the filter (optional), allow some water to flow thru
the filter, and install the outlet tube. The 1 micron pleated media filter is
readily cleaned of large particles but not necessarily of small ones or of
biological slime. To attempt to clean the filter, connect incomming water to
the outlet and connect the inlet to a drain, introduce air into the filter
housing till it is about 2/3 full of water, invert, turn on the water and
shake. (Clearly the prefilter housing is connected by flexable tubing and
easily moved. The other filter housings are best held rigidly.) If this cannot
be done, the next best method is to remove the element from it's housing and
agitate it along it's axis while submerged. If these filters are to be cost
effective, they must be effectively cleaned.
The powdered AC filters must be placed
after the bacterial filter to prevent clogging, it should be disinfected by
passing 3% hydrogen peroxode through it before useing if it has been unused for
over a week.
The granulated AC filters should be
constructed so they can be disasembled for cleaning. The media can be poured
into hot water and simmered for atleast 20 minutes. This provides partial
activation as well as removing particulates.
MORE USEFUL
PARTS
Pressure
guages, In normal use pressure should not exceed 70% of full scale.
60 PSI, 1 PSI
grad 2% accuracy 1.5" dia 3847K2
$7.21 from McM
30 .5 2%
1.5 3846K3 $10.53 McM
15 .5 cal @ 5 psi 2 $4.00 WR
Flexible pvc
tubing, easy to use for short lengths such as internal plumbing
and runing to
a near by container, can pinch off but lower pressure tubing
is more
durable when pinched off.
1/4"ID
3/8 OD 36 PSI max @ 73 deg 5233K56
$10/100 Ft McM
1/4 3/8
75 73 62501 $.13/Ft WR
5/16 7/16
30 73 5233K59 $13/100 Ft McM
5/16 7/16
46 70 FK-06405-09 $8.75/50 Ft CP
3/8 1/2
26 73 5233K63 $15/100 Ft McM
3/8 1/2
41 70 FK-06405-12 $9.75/50 Ft CP
3/8 1/2
50 73 $.20/Ft WR
1/2 5/8
20 73 5233K66 $20/100 Ft McM
1/2 5/8
28 70 FK-06405-18 $13/50 Ft CP
Silicone
rubber, Durometer
5/16 7/16
10 50 A 70
5236K14 $.73/ Ft in mult of
5' McM
5/16 7/16
>10 70 A 70
5236K69 $.73/ Ft in mult of
5' McM
2" .066 wall 80 psi polyester reinforced, lays flat until pressurized,
easyer than rigid tubing
to carry
5295K35 $.67/ft < 100
ft, $.55/ft >95 ft, mult of 5' McM
3" .078 wall 70 psi 5295K39 $1.12/ft < 100
ft, $.93/ft >95 ft, mult of 5' McM
1 micron
pleated polyester prefilter, 6 sq ft area in a
9 3/4" x 2 3/4" dia
cartridge 45235K43
$5.85 McM
Powdered
activated carbon briquette, polyolefin bonded with 2200000
sq ft effective surface E-01508-93 $26
CP
Katadyn 1040
element $90
post paid in USA Leh
(Better prices may be
available, contact me for current info.)
Katadyn 20743
element $75 post paid in
USA Leh
(Better prices may be
available, contact me for current info.)
PVC holder
for 1040 element from 2.5" pipe, includes air vent and 6" outlet
tube with pinch off clamp,
element mounting nut, press on
cleaning cap, mini wash
bottle $20 WR
For screw on quick connect mounting
adapter for more secure
outlet hoze connection especially with
outlet pressure above
5 PSI, specify 1/4 or 3/8" hoze
connection add $3 WR
Nut only for your own holder $3 WR
Cap with 3/8" FPT outlet only, for your
own holder (mounts filter
element to holder and provides 3/8"
FPT outlet) $6 WR
PVC holder
for 1700 element from 2" pipe, includes air vent and 6" inlet &
outlet tube with pinch off clamp, screw on
quick connect mounting
cap (provides quick connection to 1/4 or
3/8 hoze (specify which)) & cleaning cap, mini wash bottle $12
WR
Cap with 3/8" FPT outlet only, for your
own holder $6 WR
Multi element
assemblys useing these holders and pressure guage can be made to
order, specify circular (up to 6 elements
for carying in a bucket) or
linear (with it's own housing and optional
empty position for post filter)
Bulk head
connector, suited for mounting a tube to the bottom of a bucket
1/4" hoze barb $4, with holder for
prefilter or screen $9 WR
3/8" hoze barb $5, with holder for
prefilter or screen $9 WR
1/2" hoze barb $4.50, with holder for
prefilter or screen $10 WR
Life guage -
a flexable tape measure (Katadyn suggests the end
of life is when the diameter is 1.5"
but if there are no thin spots,
a low pressure system can use them a
little longer. If you find any
micro cracks in the filter element, you
reached end of life.) $1 WR
Cleaning pan,
Don't forget to have something to clean the Katadyn elements
in. It is best to lay the filters
horizontally partially submerged when
cleaning but a 5 gallon bucket would do.
Source Codes:
McM McMaster-Carr Supply Co., POB 4355, Chicago,
IL 60680 708-833-0300
CP Cole-Parmer Instrument Co., 625 E. Bunker
Court, Vernon Hills
IL 60061 800-323-4340
Leh Lehman Hardware,POB 321, Kidron, OH
44636 330-857-5757
RC Rockland Corp, 12320 E.Skelly Drive, Tulsa,
Ok 74128 800-258-5028
WR Wayne Robey, 215 S. 6th St, Lafayette, IN
47901 765-742-7850
All prices
subject to change without notice, prices marked WR are only intended for those
participating in Rainbow gatherings since this is a not for profit undertaking
on my part. Others may enquire. Shipping is additional unless otherwise
indicated. I can supply any parts listed herein but for additional shiping
charges which will vary with my inventory.
revised 08/8/99 by Wayne Robey