20320130406033

International Journal of Advanced Research in Engineering RESEARCH IN ENGINEERING
INTERNATIONAL JOURNAL OF ADVANCED and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME

AND TECHNOLOGY (IJARET)

ISSN 0976 - 6480 (Print)
ISSN 0976 - 6499 (Online)
Volume 4, Issue 7, November - December 2013, pp. 290-296
© IAEME: www.iaeme.com/ijaret.asp
Journal Impact Factor (2013): 5.8376 (Calculated by GISI)
www.jifactor.com

IJARET
©IAEME

DEVELOPING A TEST RIG FOR STRING WOUND FILTER CARTRIDGES
USING WATER AS THE MEDIUM
Mrs. Pragnya S.Kanade* and Dr. (Prof) Someshwar S.Bhattacharya*
*Textile Engineering Department, Faculty of Technology and Engineering,
M.S.University of Baroda, Vadodara-390001.

ABSTRACT
String wound filter cartridge is one of the most popular filter media available due to its lower
cost. The performance of this media is judged based on its performance in terms of its rating and
pressure characteristics which can be done using a destructive test method. As far as the complexity
of a testing apparatus is concerned in terms of instrumentation and controls required, single pass test
by far the simplest of all the destructive test methods. Since this is a special type of test all
laboratories/institutes may not have this testing facility. This paper gives an insight to the various
problems faced while developing a filter testing apparatus following single pass test method using
water as the media.
Keywords: Commercial Cartridge Winder, String Wound Cartridges, Test Method, Test Rig.
1. INTRODUCTION
Lot of work has been reported on the various test methods available for different filter types1,
. The performance of a cartridge can be done using destructive or non-destructive test methods
but a non-destructive test will be able to show the changes in the pressure/flow-rate conditions with
time along with changes in the number of particles observed in the filtrate. The measurement of
particles observed can be done in-line by the use of automatic particle size counters, while if off-line
measurement is opted for then the particle size analyzer (coulter counter) or optical microscope can
be used. Development of one such work is reported4 and this paper is further extension of the same
work. This paper shares the results showing how the test method has been validated. The objective of
the test method was to develop a testing facility for string wound filter cartridges so that its
performance can be judged.
2, 3 & 4

290

International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –

2. MATERIAL AND METHOD
The test rig was designed to work on single pass test method using water as the test medium.
Thus as far as the test equipment was concerned it was clear that the requirements would involve a
pump, flow meter and pressure measuring device. Literature recommends the use of a transparent
housing7 & 8 so that the cartridge can be observed during test trial also. Hence the initial design given
to the fabricator is as shown in figure 1, had a housing that was made from acrylic. The part labeled
tank was of stainless steel as provided by the fabricator whereas the pump was of tulu make of 0.5
H.P. The flow meter was of local make and the acrylic cylinder with an inner diameter of 80 mm was
given tangentially entry point so that the water spirals, creating a vortex before reaching the top.
The construction of the cylinder provided by the fabricator as per design supplied is already
shown in figure 2.
Pressure ports (inlet &
outlet)
Transparent
housing
Tangential entry

Exit point

Figure 1
Top and bottom discs were prepared. A flange was fixed on the top and bottom edges of
the cylinder using chloroform. Now the top and bottom discs prepared were clamped to the flanges
on the cylinder thus sealing the housing. ‘C’ clamps were used to fix the top flange on the top disc.
Care had to be taken that the water does not leak between the cartridge and the bushes provided
inside the housing. This was checked by fixing a test PVC pipe of 10” (without perforations) inside
the housing and running the pump, at the outlet no water was collected and this was the indication
of zero leakage between the test PVC pipe and the bushes.

291


Inlet of water to the housing (tangential)
Tangential entry

Figure 2

This design did not yield results and the reasons are mentioned as follows. The ‘C’ clamps
used for sealing did not prove to be effective with higher pressure. Leakage was observed in most of
the cases, which was taken care by providing PU fittings. To overcome the problem of higher
pressure, instead of mercury, CCl4 was used but then difficulty was observed in locating the
meniscus and taking the pressure readings. The tank used in this case was having a very small
capacity therefore if uninterrupted water supply was needed then its capacity would have to be more.
Hence two tanks were now added having larger capacity, one served as the mixing tank while the
other as the supply tank. The float in the flow meter kept fluctuating, which was stabilized by
introducing a by-pass valve. Since the exit point (figure 1) was kept open due to which the water
column did not develop sufficiently and hence bubbles would enter into the pressure ports provided.
This resulted in the inability to record pressure readings.
Hence it was decided to flip the entry point that is the entry point would now be at the top
while the valve at the bottom side, would be kept closed.

292


Figure 3
The changed filter testing arrangement is as shown in figure 3. the tangential entry point is at
the top and the pipe fittings were changed to plastic to reduce weight. But still it can be seen the
overhange shown in terms of bypass caused a lot of pressure to come on the acrylic entry point that
was pasted on to the cylinder. Besises there were several bends due to which also the actual pressure
exerted would change.
Since several trials had to be taken while setting up the testing rig, leakage was observed at
the tangential entry point. This was rectified by using M seal, silicon and even chloroform was used
but some how the problem persisted. Hence it was decided to make use of the ready-made housings
normally seen in the household filtration units. The line diagram of the apparatus developed is shown
in figure 4. This also shows the use of supply tank while the mixing tank is not shown. Here it is
important to note that a stirrer is shown inside the tank meant for the purpose of creating churning
action thereby preventing the particles from settling. The revolution of both the stirrers was
maintained almost same around 40 rpm. The radial arrangement of the blades inside the tank was set
different to create better effect.

293


Figure 4

RESULT AND DISCUSSION
The testing equipment developed was supposed to be working on single pass and constant
flow-rate conditions5 & 6. If in the operating condition some definite value of flow-rate is fixed upon.
Then for the entire period of test time the same has to be maintained, which would obviously result
in the increase in pressure. Unlike the test conditions where constant pressure is aimed at would
result in reducing flow-rate. It should be visualized that the water would be artificially contaminated
by a known test contaminant. Initially the cartridge would be clean but when persistent attack of
contaminated water occurs on it, it will become loaded with those particles. This will reduce its
porosity thereby reducing the flow-rate. Now if this has to be maintained constant then there had to
be some arrangement whereby the flow-rate could be brought back to the original. Bypass valve seen
in the figure 4 would help in achieving the said purpose. To verify, test trials were conducted on
several cartridges, a few have been shown to prove that the test-rig developed works on constant
flow-rate. Figure 5 shows the pressure characteristics of a cartridge given code of A1 where as figure
6 shows the same plot for cartridges coded A2 and A3. As it can be seen that the inlet pressure
continuously increases as the flow rate is made to remain constant. The outlet pressure almost
remains constant since this water is discharged to the atmosphere. The pressure drop shows the same
characteristics as the inlet pressure with lower magnitude.

294


PRESSURE CHARACTERISTICS OF A1
16.000

Inlet pressure
Outlet pressure

PRESSURE DROP (PSI)

14.000

Pressure drop

12.000
10.000
8.000
6.000
4.000
2.000
0.000
0

20

40

60

80

100

120

140

TIME (MIN)

Figure 5

PRESSURE CHARACTERISTICS OF A2 and A3

14.000

PRESSURE (psi)

12.000
Inlet A2

10.000

Otlet A2
8.000
Inlet A3
Outlet A3

6.000
4.000
2.000
0.000
0

20

40

60

80

100

120

140

TIME (MINS)

Figure 6

These cartridges were produced on newly fabricated winder; hence it was necessary to
compare its performance with a commercially used winder. The figure 7 shows test results of a
cartridge produced on commercial filter winder.

295

PRESSURE CHARACTERISTICS OF CARTRIDGE PRODUCED
ON COMMERICAL FILTER WINDER
inlet pressure

16

outlet pressure
14

pressure drop

PRESSURE (psi)

12
10
8
6
4
2
0
0

20

40

60

80

100

120

140

TIME (MIN)

Figure 7

CONCLUSION
Thus a filter winder has been successfully developed working on single pass test method with
water as medium and providing constant flow-rate conditions. Though transparent housing could
have been an added advantage, the results are nevertheless satisfactory. The same equipment can be
modified to work on multi-pass test method provided, the necessary instrumentation is included. The
analysis of the filtrate has been done using microscope but with a multi-pass test method, use of
automatic particle size counters would become inevitable.
REFERENCES
1. Williams C.J, 1992. Testing the performance of spool-wound cartridge filters, Filtration &
Separation, 29(2), 162-168.
2. Hoeg A., 2009. A better way to rate filter performance, Korane J.K. (Ed.),
www.machinedesign.com/archive/better-way-to-rate-filter-performance, accessed August
2013.
3. Jourdan M.-F. and Peuchot. C, 1994. New test methods for evaluation of water cartridge filters,
Filtration & Separation, 31(5), 427-434.
4. Mrs. Kanade P.S, Dr. (Prof) Bhattacharya S.S, “ Influence of winding parameters on the
performance of string wound filter cartridges – Part – I”, The filtration journal, Vol.13 no. 4
Oct 2013, pp 222-231
5. ASTM F 795-88, Standard practice for determining the performance of a filter medium
employing a single-pass, constant rate, liquid test, Dec 1988 (964).
6. ASTM F 796-88, Standard practice for determining the performance of a filter medium
employing a single-pass, constant pressure, liquid test, Dec 1988 (970).
7. Williams C J and.Edyvean R G J. Testing cartridge filters in aqueous media: Interpreting the
results – The pitfalls and problems. Part – I: Evaluating the performance methods. Filtration &
Separation 1995; 32: 157-161.
8. Celio M, Arruda A C F. Application of X-ray computerized tomography to characterize particle
retention within depth filters. Part. Part. Syst. Charact. 2000: 17, 28-32

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