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Assessment of Oriental Water Filter Age (Lifetime)


I’ve labored with 3D-printing business for many years: the actual spraying of the fabric (not dispense the molten materials by means of a die). We used 300 dots per inch to create strong objects and the print head contained 1200 nozzles. Constructing one Eight-inch-high object was equal to printing 5,000 pages.

Delivering a print head with clean material was of paramount significance for printing reliability and longevity. To measure this drawback, a unit of measure was developed to guage the purity of the material sprayed. That is referred to as conductivity testing. To perform the check, the liquid was placed within the check equipment and the fluid degree was stored constant – this might give a gentle fluid strain. Downstream of the vessel was standardized filter materials. The liquid was allowed to stream by way of a filter and knowledge was collected. To create a conductivity diagram, you plot the real-time move price of the liquid by means of the filter material (Y-axis) with the entire amount of liquid passing by way of the filter (X-axis). The chart exhibits a straight line with a adverse slope: high on the left and reducing on the correct.

The straight slope provides us the speed at which the filter is clogged, or in different words, a measure of the purity of the fabric. The minimum stream fee is decided by the performance requirements needed to properly spray the fabric. The full quantity of material sprayed is decided by the advertising requirements. Use this chart to find out what number of cubic meters (or kilos) of material could possibly be sprayed before the movement fee drops under a suitable degree.

 Conductivity 2

The check meter is superb for verifying the purity of the material. , so we will use this to estimate the efficiency of rural water filters.

Nevertheless, we’ve no management over the standard of water in an city space. Modifying the check technique to estimate the efficient filter area adds far more worth to characterizing the water filter efficiency status.

This sort of check can be straightforward to repeat for water filters and the results can be highly reproducible. The system used to guage the standard of 3D print media described above is giant and requires further gear that may make it troublesome for most backpackers to mimic.

So, in this article, I recommend a faster and easier to make use of check that, whereas not as correct, is straightforward to reproduce and is user-friendly enough for most backpackers.

The aim of this check is to determine the actual age of a backpack water filter in comparison with

I developed this check technique utilizing the Sawyer Squeeze and Sawyer Mini filters as they are in all probability the 2 hottest filter fashions used by the light-weight backpacking and tenting group.

You’ll be able to estimate the lifetime of your Sawyer filter with a reasonably easy check setting. The check requires measuring the stream fee of the new filter to find out the baseline.

Darcy's regulation is used to describe the move of liquid by means of a filter medium. Nevertheless, this requires that there are not any particles within the liquid. By including the idea that the filter will develop into clogged over time, you’ll be able to estimate the filter life by calculating the discount in effective filter area. By observing the movement fee, you’ll be able to estimate the quantity of filter remaining within the filter (effective remaining filter space). In addition, you’ll be able to see the rinse impact to revive filter life.


Supplies Required

  • Saw Filter (or some other filter capable of gravity filtering mode)
  • 1 liter Smartwater Bottle [19659016] Digital Scale


Step 1: Drill Gap for Smartwater to the bottom. The opening ought to be small enough (~ three/16 ”or 5mm) to stop your finger from leaking into the bottle. This is required to stop the formation of a vacuum during filtration into the water bottle, which affects repeatability by altering the movement fee.

  IMG 2988

  IMG 2989

Step 2: Make certain your filter is moistened: I put the mine in a full glass of water in a single day.

Step 3: Fill the sink (or bucket of water) full of water.

Step four: Immerse the bottle utterly in water and take away any trapped. air. Do the same with the filter and fasten the two, holding them underwater. Within the following picture, the meeting is totally submerged underneath water.

 IMG 2986

Step 5: Place your finger over the opening in the bottom of the water bottle and raise the bottle / filter assembly out of the water. Water should not circulate from the filter (there may be a number of drops of residue and it is wonderful.)

Step 6: Place the bowl on the scales and cargo the scales. Step 7: Suspend the bottle / filter in a bowl. Launch your finger from the vent and activate the stopwatch.

 IMG 2985   IMG 2987

Step 8: When the size reads 500 grams (16.9 oz). , report the time (in seconds) and finish the check.

Check Results

Check by reference a model new (unused) Sawyer Squeeze filter and a used Sawyer Squeeze filter. The filter I used has been my go-to filter for the final five years. I have not been cautious to rinse the filter or perform maintenance after my travels. I also haven’t any clear concept of ​​how a lot water has been via the filter.

The check was performed 3 occasions. For good repeatability, I decided not to embrace extra playback occasions. The identical batch of water was utilized in all experiments and the water temperature remained constant. After the check, the filtered water was poured again into the primary water tank. The experiment was restricted to 500 ml (16.9 oz) for two reasons. First, I was frightened concerning the results of a lowered strain head over time (h). Because the water degree drops, the move velocity will increase and should improve errors in measurements. Second, my digital scale goes out after three minutes, so the quantity change (ΔV) had to be controlled.

The following desk summarizes my outcomes with the brand new filter, the used filter, and the same used filter after the backwash system. :

New filter Used filter Used, newly rinsed

(in seconds)

57 103 99
105 105 97
57 100 98
common 56.7 102.7 98.0

Darcy's concept and knowledge analysis the regulation was first used by means of a fluid permeable to the motion of the picture (e.g., move of water via filth and sand). Designers have used Darcy's regulation for decades as a result of of the nature of the filter's efficiency. The essential equation is outlined under:

Okay = (ΔV * L) / (Δt * A * h)


  • Okay = hydraulic conductivity (volume / unit time) / filter space
  • . ΔV = change in water quantity
  • Δt = change in time
  • L = pattern size
  • A = area of ​​filter medium
  • h = strain head

. Designed filters are easier to research in comparison with clay techniques because a number of variables are beneath management.

Okay (hydraulic conductivity) is usually a design specification. A and L are determined by the bodily design of the filter. For this check, Okay, A, and L. are all constants as a result of of the performance of the same filters.

Darcy's regulation was formulated with the idea that the liquid doesn’t include impurities (particles). We will modify the formulation by assuming that as the filter becomes clogged, the effective filter space decreases.

Bearing in mind the check protocol, the preliminary quantity (V) is outlined as an entire flask and the ultimate volume occurs at the finish of the check outcome after 500 ml (16.9 oz) has been filtered. In addition, h (strain head) is geometrically fastened as a perform of bottle dimensions.

Since Okay is a real fixed between two filters of the identical structure, we will rewrite Darcy's regulation for each new and used filters: [19659002] (V * L) / (new * new * h) = Okay = (V * L / tused * used * h)

V, Okay, L & h are principally constant during all repetitive exams, in order that they depart the equation.

The components is now decreased to:

1 / (tnew * Anew) = 1 / (tused * Aused)

This can be rearranged:

Aused / Anew = tnew / tused

the ratio of space to space of ​​the brand new filter is proportional to the inverse of the time distinction of the stream charges.

Knowledge Evaluation

check knowledge in the Darcy & # 39; s Regulation components above, we will examine the efficiency I used to the brand new filter:

  • On this case, 56.7 / 102.7 (information / used) = 55%. Assuming new = 100%; In my case, backwash (3X) had little or no effect on the circulate fee (102.7 seconds versus seconds). The water quality is unknown and is filtered. volumes range. Here is a chart that speculates what can happen through the life of a filter.

     flow over volume

    . Every colour represents a special backpack. For example, the reducing slope of the strains may be a perform of particles clogged by the water column (steep strains symbolize the filtration of water at greater particle concentrations). Vertical spikes characterize attempts to re-filter. Check Outcomes

This easy check provides an concept of ​​the efficient floor space of ​​the water filter medium (in a sense it represents the gasoline gauge of the filter life).

No significant conclusions may be drawn from the results of background flushing because the historical past of the filter used is just not properly documented. Extra subject info is needed to make clear the effectiveness of again flushing, descaling, or other mechanisms to improve filtration.

In a great world, outcomes might be measured (for example) on 10 samples of new Sawyer filters to create a baseline vary for brand spanking new filters. Users can then repeat the check protocol to guage the precise effective filter floor or service life of the system used. If successful, the database might be expanded to incorporate different gravity / compression filters.

Filter Sort vs. Water Quality

Water quality throughout the world (world) could be very variable, so it’s a must to select the proper filter for the proper circumstances. When camping in and round gulf canyons and warm water sources, I often deliver my MSR MiniWorks filter as a result of I can simply clean the filter component, even in slurry-laden water. In any other case I exploit the Sawyer press for 90% of my travels.

Sawyer Press vs. Mini

Once they first appeared, the said lifetime of the Sawyer press was one million gallons (3.8M liters) of water!

A million gallons is an absurd amount of water. I knew that the one approach they might declare these numbers was to do one thing by testing continuous move (i.e., conductivity) utilizing some sort of pure model water. Sawyer was pressured to desert these claims because they might not verify the claim confidentially and had nearly zero reality.

Sawyer Mini claimed to have a filter capability of up to 100,000 gallons (380,000 liters). out of the water. It's high quality, but the Mini has an order of magnitude less filtering materials than urgent. After greater than 5 years of use and abuse, check outcomes show that my unique Sawyer Squeeze filter still has 55% of its lifetime. In terms of equivalence, it is the similar as about five Sawyer Mini filters! For my part, the Sawyer press is superior in terms of move, longevity and, above all, stability (or latitude relative to its capability to withstand clogging of problematic water sources). The most important disadvantage to compression for most people is weight. Nevertheless, the Sawyer Squeeze filter weighs just one.0 ounces (28.three gm) greater than the Sawyer Mini.

This check protocol proved very useful to me in deciding to stick with Sawyer Squeeze in terms of its efficiency – weight ratio vs. Mini, particularly in phrases of its durability (longevity).

Disclosure: Some (however not all) of the links in this assessment may be "affiliate links", which signifies that you click on to link to our affiliate partners (often a reseller website) after which make a purchase order with that reseller, we get a small reward. This helps us fund editorial tasks, podcasts, reference webinars and far more, and we drastically recognize it! Thanks on your help of Backpacking Mild!

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