Pleated Filter Cartridges Research Articles

The effect of pleat ratio on the effective filtration area of the large-diameter pleated filter cartridge

To solve the problem of point source dust in industrial production, we employed a large-diameter pleated filter cartridge (fold ratio α values of 1.23, 1.47, 1.7, and 1.8). However, its complex pleated structure affects the stable operation state of the dust collector. The experimental results show that with the gradual increase of the fold ratio of the filter, the filter cleaning efficiency ε increases at first and then decreases, and an α value of 1.47 shows the best results. The average effective filtration area Ae ¯ increases with increasing fold ratio over the same run time. The higher the dust concentration, the lower is the Ae ¯ ; the ratio of the average effective filtration area to the theoretical filtration area β ¯ decreased from 80.2% (α = 1.8) and 80% (α = 1.47) to 77% (α = 1.7).

Numerical study on the design of multi-staged, opposing pulsed-jet cleaning (M-OPJC) for pleated filter cartridges

Opposing pulsed-jet cleaning (OPJC) has recently been proposed as a method to improve the filtration media regeneration of pleated filter cartridges, specifically addressing the patchy cleaning issue typically encountered in conventional pulsed jet cleaning. In this study, we first investigate the effect of pressure ratio (PR, the ratio of pressures at the opposing nozzles) on the OPJC performance in terms of cleaning intensity, uniformity, comprehensive pressure, and cleaning efficiency for pleated filter cartridges. A new OPJC strategy, named multi-staged, opposing pulsed-jet cleaning (M-OPJC), is proposed to enable the movement of a high-pressure region (formed by the collision of the pulsed-jet airflows introduced from opposing nozzles) within the core of a filter cartridge during the cleaning. The M-OPJC divides one cleaning jet cycle into four jetting stages with different PR values. Among all the evaluated cases, the M-OPJC with PR = [1.00, 1.00, 1.33, 2.00] offers the best cleaning performance for a pleated filter cartridge. Compared to conventional pulsed-jet cleaning (i.e., M-OPJC with PR = [0, 0, 0, 0]), the M-OPJC method increased the peak pressure at the cartridge’s upper part by 325.93%, comprehensive pressure by 171.10%, and cleaning efficiency by 48.85%.

Modeling and Cleaning Performance Optimization of Conical Filter Cartridge of Gas Turbine Intake Filter

Intake quality is crucial to gas turbines’ operation. The cartridge filter in the gas turbine intake system filters the gas and outputs a highly clean gas into the gas turbine, while pulse cleaning technology ensures the continuous and efficient operation of cartridge filters. While the current cylindrical pleated filter cartridge used in pulse cleaning usually suffers from insufficient upper cleaning, the conical pleated filter cartridge can effectively solve this issue by providing a greater upper cleaning area with significant application prospects. Despite the existing potential, research on conical filter cartridge cleaning performance is limited; thus, this paper aims to investigate the advantages of pulse cleaning using a conical filter cartridge via numerical simulation. Results demonstrate that while the conical filter cartridge enhances the cleaning strength, cleaning uniformity decreases slightly. To address this shortcoming, this paper innovatively proposes a combination of scattering nozzles and conical filter cartridges to explore the impact of the installation position of scattering nozzles on the cleaning. The modeling and cleaning performance analysis in our research illustrates that the optimal cleaning effect can be achieved under specific conditions when the scattering nozzle is installed parallel to the conical filter cartridge’s inlet. The research work in this paper provides a solution for optimizing the pulse cleaning performance of conical filter cartridges.

Inhibition of Dust Re-Deposition for Filter Cleaning Using a Multi-Pulsing Jet

The re-deposition of detached dust during online pulse-jet cleaning is an important issue encountered during filter regeneration. To reduce dust re-deposition, multi-pulsing jet cleaning schemes were designed and experimentally tested. A pilot-scale pulse-jet cleaning dust collector was built with one vertically installed pleated filter cartridge. The effects of pulse duration and interval on the pulse pressure were tested, and the dust re-deposition rate and mechanism were studied and analyzed. It was found that, for the single-pulsing jet, the pulse duration had a critical value of approximately 0.080 s in this test, above which the pulse pressure remained at approximately 0.75 kPa and did not increase further. For the multi-pulsing jet with a small pulse interval (less than approximately 0.10 s), the pulse flows superimposed and reached a higher pulse pressure with a slight inhibition of dust re-deposition. For the multi-pulsing jet with a long pulse interval (over 0.15 s), dust re-deposition was clearly inhibited. The re-deposition rate decreased from 63.8% in the single-pulsing scheme to 24.4% in the multi (five)-pulsing scheme with the same total pulse duration of 0.400 s. The multi-pulsing scheme lengthens the duration of reverse pulse flow, resulting in more elapsed time for the detached dust to freely fall, and inhibiting the re-deposition of dust. The elapsed time in the five-pulsing jet scheme with the recommended pulse duration of 0.080 s and interval of 0.25 s was 2.8 times higher than that of the single-pulsing jet with the same total pulse duration.

Improved Pulsed-Jet Cleaning of Pleated Cone Filter Cartridges Using a Diffusion Nozzle

A pleated filter cartridge with an additional pleated filter cone installed on the cartridge base, i.e., a pleated cone filter cartridge, has been proposed to increase the filtration area and to improve medium regeneration by reverse pulsed-jet cleaning. In this study, the pulsed-jet cleaning performance of a pleated cone filter cartridge in a dust collector was investigated using a diffusion nozzle (as compared to that of a round nozzle). The effects of tank pressure (TP), jet distance (JD), and inner cone height (HC) on the distribution of static pressure acting on the inner surfaces of the cone filter cartridges were evaluated. The filtration pressure drops and emitted dust concentration of cartridges during the dust collector operation were also measured. It was found that, using a diffusion nozzle, the pulsed-jet pressure at the upper portion of the filter cartridges was increased, compared to that of a round nozzle, particularly for cartridges with a low HC and a short JD setting (e.g., a factor of 7.0 was observed when HC = 560 mm and at a JD setting of 150 mm). The pulsed-jet cleaning of a pleated cone filter cartridge using a diffusion nozzle can decrease the residual filtration pressure drop, prolong the cleaning interval, and reduce the average dust concentration emission from cone filter cartridges.

Performance characterization of a novel compact dust collector with pleated filter cartridges

A compact dust collector loaded with four pleated filter cartridges is numerically studied by Computational Fluid Dynamics (CFD). The performance of the dust collector is evaluated during filtration and during backwashing, and the predictions are compared with the experimental results. In the filtration operation, the upper right corner entry design effectively guides the airflow to the two sides of the four cartridges through the air opposite-side-wall impacting and rebounding. A relatively poor filtration is found at the right side of the left lower cartridge. The CFD predictions agree well with the experimental data in terms of showing better backwash cleaning performances of the lower cartridges and at the cartridge front positions. During the 50 ms pulse-jet backwashing, the difference between the maximum and minimum air mass flow rates through a total of 16 × 2 inject holes is less than 4.0%. The high pressure of 0.5 MPa draws the air flowing from the normal exit, which acts as the majority of the backwashing air (ca. 73.7%). The hydrostatic pressure acting on the four cartridges is greater than 1750 Pa in 80% of the pulse-jet cleaning time.

Improved performance of the opposing pulsed-jet cleaning by annular-slit nozzles for pleated filter cartridges

The opposing pulsed-jet cleaning with round nozzles has been recently introduced to reduce the patchy cleaning often faced during the regeneration of pleated filter cartridges in dust collectors. Additional to the primary nozzle for jetting a cleaning flow, the above technology applies an auxiliary nozzle installed at the cartridge base to launch a second flow for the cleaning. To further improve the performance, this study proposed to adopt an annular-slit nozzle as the primary-one in the above cleaning. The numerical modeling was applied to investigate the flow and pressure fields in a dust collector under the above cleaning with the settings varying the jet distance, h, from 0 to 700 mm, the delay time, Δt, from −0.125 to 0.125 s, and the pressure ratio, PR, from 0 to 4. The peak intensity and uniformity of the static pressure on the inner wall surfaces of filter cartridges during the cleaning were selected as the indicators for the cleaning performance. It is found that the cleaning performance in the cases with an annular-slit nozzle was found to be generally better than that in the cases with a round nozzle. Using an annular-slit nozzle, the air entrainment effect was enhanced, and the collision of both opposing jet flows was occurred in the position much closer to the cartridge opening. The cleaning in the case of Δt > 0 s was in general better than that in the cases of Δt < 0 s (with the optimum achieved at Δt = 0.025 s). The reasonable PR was in the range of 0.5 to 1.5 to realize effective jet airflow collision. The cleaning intensity and C.V. in the cases with an annular-slit nozzle and under the suggested settings of h = 300 mm, Δt = 0.025 s and PR = 1.5 would achieve the values of 1,050 Pa and 0.13 respectively, resulting in the 27 % and 63 % improvement on average (compared to those in the case using a round nozzle).

Effect of jet airflow deflection on cleaning performance of filter cartridge.

Pleated cartridge filters are widely used to remove dust in industrial processes. However, pulse-jet cleaning is not uniform on the filter cartridges. The phenomenon of pulsed jet airflow deflection exists during pulse jet cleaning, which causes a large impact on the local area of filter cartridge and shortens the service life of the filter cartridge. But perhaps due to the lack of effective testing methods, the impact of pulsed jet deflection on dust cleaning is often ignored. Under more comprehensive conditions, such as jet pressures, jet distance, and jet-hole diameter, the influence of the pulsed jet airflow deflection on the cleaning performance of the filter cartridge has been discussed systematically, by testing the peak static pressure on the side wall of the filter cartridge. The experimental results show that the sidewall peak static pressure of the face-flow surface of the filter cartridge is greater than that of the back-flow surface due to deflection, and the difference between the two is proportional to the jet-hole diameter and jet pressure. After installing the diversion nozzle, the results show that the peak static pressures of the face-flow and back-flow surfaces are basically the same. Therefore, it is proved that the diversion nozzle can effectively correct the jet airflow deflection.

Modeling of the Effects of Pleat Packing Density and Cartridge Geometry on the Performance of Pleated Membrane Filters

Pleated membrane filters are widely used to remove undesired impurities from a fluid in many applications. A filter membrane is sandwiched between porous support layers and then pleated and packed into an annular cylindrical cartridge with a central hollow duct for outflow. Although this arrangement offers a high surface filtration area to volume ratio, the filter performance is not as efficient as those of equivalent flat filters. In this paper, we use asymptotic methods to simplify the flow throughout the cartridge to systematically investigate how the number of pleats or pleat packing density affects the performance of the pleated membrane filters. The model is used to determine an optimal number of pleats in order to achieve a particular optimum filtration performance. Our findings show that only the “just right”—neither too few nor too many—number of pleats gives optimum performance in a pleated filter cartridge.

The relationship between peak pressure and parameters of pulse-jet cleaning in a sintered plastic filter

ABSTRACT Sintered plastic filters are recently favored in industrial filtration systems because of their advantage of high filtration precision and long service life. In order to embody experimental characterization of pulse-jet cleaning of sintered plastic filters, tests were concluded on a self-made pulse-jet cleaning experimental platform. The cleaning characteristics of sintered plastic filters were investigated with varied pulse-jet parameters of tank pressure, nozzle diameter, and jet distance (the distance between nozzle and filter opening). The relationship between pressure distribution and pulse-jet cleaning parameters was established. The results showed that peak positive pressure on the corresponding sintered plastic filter inner wall increased with the increasing tank pressure. With the increasing jet distance, peak pressure first increased, then decreased, and with the increasing nozzle diameter, the optimum jet distance decreased gradually. At the optimum jet distance, the peak pressure with a nozzle diameter of 6 mm was the best, which was confirmed through the jet flow photographed by schlieren. The mathematical model obtained by curve fitting was s = (d – a)/2. These results indicated that there was a direct relationship between the peak pressure and the parameters of pulse-jet cleaning in a sintered plastic filter. It provided theoretical support and application foundation for industrial dust-cleaning design. Implications: Sintered plastic filter is a new generation of high efficiency dust collector. Generally, its characteristics can be divided into three major categories as follows. 1) In terms of materials, the sintered plastic filter is made of PE substrate and coated with PTFE membrane, which makes it have stable chemical properties and can be used in high humidity, high oil, and other special situations. 2) In terms of dust cleaning, sintered plastic filter has high dust-cleaning efficiency of ultra-fine dust because of the unique membrane, which is not only limited to the surface of the filter plate, but also penetrates into the interior of the interstice. 3) In terms of structure, the sintered plastic filter is a rigid wavy porous structure filter of nine cavities formed by special sintering process of polymer material. This filter elements of integrated rigid design make its physical structure strong, not easy to deform and damage, and with a longer service life than traditional filters (bag filters and pleated fabric filter cartridges). In order to embody experimental characterization of pulse-jet cleaning of sintered plastic filters, tests were concluded on a self-made pulse-jet cleaning experimental platform described in this article. The cleaning characteristics of sintered plastic filters were investigated with varied pulse-jet parameters of tank pressure, nozzle diameter, and jet distance (the distance between nozzle and filter opening). The relationship between pressure distribution and pulse-jet cleaning parameters was established. These results indicated that there was a direct relationship between the peak pressure and the parameters of pulse-jet cleaning in a sintered plastic filter. It provided theoretical support and application foundation for industrial dust-cleaning design.

Reverse pulsed-flow cleaning of pleated filter cartridges having an inner pleated filter cone

Different from conventional pleated filter cartridges, which apply pleated filter media as the cartridge sidewall, seal one end as the base and open the other end as the entrance for cleaning flow, ones with inner pleated filter cones, called as cone pleated filter cartridges, have been recently proposed to increase the filtration area and to improve the efficiency of the reverse pulsed-flow cleaning. This work investigated the cleaning performance of cone pleated filter cartridges via the numerical modeling. Our modeling shows that, for a cone pleated filter cartridge cleaned by a reverse pulsed-flow, a high- and low- pressure zones were developed in the inside spaces close to the open and sealed ends of filter cartridges, respectively, and the variation of static pressure was observed in the radial cross section of filter cartridges was negligible. For cone pleated filter cartridges with a low cone height HC (i.e., < 660 mm, the cartridge height), a negative pressure zone was found in the inside region near the open end of cartridges. Two events of pressure waves were experienced during the cleaning of cone pleated filter cartridges. Between both wave events, the first one was significantly affected by HC. As the HC was increased, the overall cleaning intensity developed inside the cartridges was topped for filters with HC = 760 mm and then decreased. In addition, the cleaning uniformity of cone pleated filter cartridges was generally improved compared to to that for ones without pleated filter cones.

Nitrogen pulse jet cleaning of the pleated filter cartridge clogged with adhesive hygroscopic dusts

The pleated filter cartridges are widely used in industrial production to control particulate emissions and recover valuable particulate matter, where pulse jet cleaning is a major method for filter regeneration. However, for strong hygroscopic and adhesive dust such as Polyacrylamides (PAM), during pulse-jet cleaning the compressed air forms a low temperature zone at the nozzle and will release water to the environment, causing the particles to adhere on the filter after absorbing moisture, resulting in ineffective filter regeneration. Therefore, a higher cleaning pressure or other methods are required to clean the filter surface. In this article, we have proposed a method to collect adhesive dust using dry gas injection and verified its feasibility through pilot experiments. The compressed air injection source was replaced with nitrogen, the curve of system pressure drop shows that nitrogen has good performance in the peeling of adhesive dust from the surface of the pleated filter cartridge. This highlights the effect of the moisture content in the cleaning compressed air on the regeneration of filters clogged with adhesive hygroscopic particles. Therefore, the feasibility of the nitrogen injection was validated, which provides a basis for the future systematic research of industry to collect adhesive dust.

Performance optimization of rectangular flat pleated filter with slit nozzle for dust cleaning

This work attempted to explore the causes of incomplete cleaning on the top of rectangular flat pleated filter cartridges, and designed newly developed slit nozzle to remove the caked-on dust of the dead zone. In this study, 7 slit holes (length 39 mm × width 1 mm) were designed to compare the peak pressures on the surface of the filter with circular nozzle (7 holes per pipe and the diameter of each hole is 7 mm) under the pulse pressures of 0.3 and 0.4 MPa, the jet distances of 20–100 mm, the filtration velocity of 0.8 m/min and the dust mass concentration of 20 g/m3. The experimental results showed that the optimum distance of circular nozzle was 20 mm, while that of slit nozzle was 20–40 mm, which can enlarge the application range of jet distance. Under the optimum distance, the pressure difference between the upper measuring point P1 and P4 was above 1000 Pa with circular nozzle, while that between the point P1 and P4 was below 400 Pa at the same conditions with slit nozzle. The experimental results also showed when the jet distance was less than 40 mm, the residual dust and systematic resistance under slit nozzle were lower than those of circular nozzle. The newly developed slit nozzle overcame the cleaning difficulty on the top of the filter cartridge and was beneficial for the industrial application.

Improvement of Constructions and Methodological Approaches in the Development of Two-Stage Gas Purification Devices Equipped with Parallel Flat Filter Cartridges Interconnected within One Vessel

The article presents improved approaches to increase throughput capacity of a two-stage natural gas purification device by placing a row of parallel flat filter cartridges interconnected within one vessel with the inlet and outlet nozzles attached from different sides of the filter at the same height. The use of two-stage filters with the inlet and outlet nozzles attached from different sides of the filter allows to reduce the distance between adjacent gas reduction lines. Placing of the inlet and outlet nozzles at the same height decreases the height of the wall constructions required to place the reduction lines. The use of proposed gas purification devices allows the following: to increase the purification device capacity due to compact placing of the filtering surface in a unit volume of its vessel; to perform flexible increase in the filtering surface of the purification device due to the possibility of placing additional purification units into the device without reconstructing gas reduction cabinet; to reduce the cost of purification by increasing the total area of filtering cartridges and, consequently, reducing the number of cleaning operations; to reduce the area of the place allocated for purification device, as well as to reduce heating costs. We obtained the dependence regarding definition of specific integral area of parallel pleated filter cartridges, taking into account the filtering surface shape and geometrical parameters of the pleats. As a result, we came up with a formula to evaluate the efficiency of placing filtering surface within the vessel of the proposed purification device with parallel filtering cartridges, as compared with the most advanced analogue with a single cylindrical filter cartridge.

Characterization of pressure drop through two-stage particulate air filters

A common form of particulate air filters is the pleated filter. The pressure drop and particle removal efficiency are the most important performance indicators of this filter. A computational fluid dynamics (CFD) tool was utilized to predict the pressure drop of a two-stage filter cartridge. In the CFD analysis, the flow through the porous medium was used as an indicator of the pressure drop in the filter. The pressure drop of the two-stage filter was predicted through an experiment involving a single-stage filter at 1 m/s. The pleated filter cartridge size was 361 × 277 × 25 (L × W × H) mm3 and the pitch of the pleats was 3.8 mm. Four classes of filters (E10, E11, E12, H13) were used in the experiments. The filter resistances of the four grades were estimated through the single-stage filter experiment, and the pressure drop of the two-stage filter was predicted at 0.5–1 m/s. To verify the predicted CFD analysis values, two-stage filters were fabricated and tested at 0.75 m/s. For the E12 + H13 combination filter, the analytical value was 111 Pa, which agreed with the experimental value of 109.9 Pa. The other filters exhibited an error of <2%.

Effects of Overall Length and OD on Opposing Pulse-jet Cleaning for Pleated Filter Cartridges

ABSTRACT Opposing-pulse-jet technology has been proposed as a solution for regenerating filtration media by minimizing the incomplete cleaning of pleated filter cartridges. In this study, we investigated the effects of a pleated filter cartridge’s overall length and outer diameter (OD) on the performance of opposing-pulse-jet cleaning via numerical modeling. For each pleated filter cartridge, the delay time, Δt (defined as the delay in launching the secondary nozzle), was varied to analyze the intensity and the uniformity of the static pressure distribution in the core of the cartridge. It was found that two opposing jet flows collided much more intensely in the core when the length of the overall cartridge, L, was short, and the OD was small. For a given L, the pressure pulse’s performance was maximized by varying Δt. The pulse intensity and uniformity in the filter core can be represented as a bimodal (double-peaked) function of Δt. In general, the pulse intensity was greater when Δt > 0 s than when Δt < 0 s (when the secondary jet was launched before the primary jet).

Pleatco Filtration purchases TVS Filters

Pleatco Filtration has bought TVS Filters, a designer and manufacturer of pleated filter cartridges, gas turbine inlet filters and other filtration products for complex industrial air filtration applications.

Numerical study of opposing pulsed-jet cleaning for pleated filter cartridges

Pleated filter cartridges are recently favored in industrial filtration systems because of their advantage of the large filtration area. Their use, however, places the serious concern of incomplete/patchy cleaning via reverse pulsed-jet technique. A new pulsed-jet technique, named opposing pulsed-jet cleaning (previously colliding pulse jet cleaning), had been proposed and experimentally evidenced to improve the cleaning quality of pleated filter cartridges. In the above cleaning, a second cleaning nozzle is installed at the cartridge base and its exit, facing the cartridge core, is used to launch a second pulsed-jet flow in addition to the primary one. Via the numerical modeling, this work investigated the detail flow mechanisms in the cleaning process and the effects of delay time, Δt, and pressure ratio, PR, on the cleaning performance. It was found that, within a certain range of Δt, the later-initiated jet from the second nozzle would collide with the former-launched jet from the primary one, and the flow impinging location could be moved inside the pleated cartridge, resulting in wider filtration media area covered by the impinging jet flow energy (compared with that using only the primary nozzle). The cleaning performance could also be improved by the increase of PR when Δt > 0. When Δt = 0, the cleaning quality reduces as the PR value increases to 1.5 and remains the same when the PR value is greater than 1.5. Under the scenario of Δt < 0, the cleaning performance improves as the PR increases and then reduces as the value of PR further increases.

Effect of novel built-in rotator on the performance of pleated cartridge filter

Large quantities of PM (particulate matter) produced in the construction process poses hazard for both the workers' health and the whole environment. Despite the wide application of cartridge filters to PM collection, incomplete cleaning often occurs during pulse-jet cleaning of common nozzles. In this study, a built-in rotator used in a larger-diameter pleated filter cartridge was developed to improve the effect of pulse-jet cleaning. Then, the pulse-jet cleaning performances between the built-in rotator and the common nozzle were compared. The results show that the pressure drop of the built-in rotator is similar to that of the non-built-in one under the same superficial filtration velocity. The number of rotations grows with the increase of high-pressure air, while it first increases and then remains stable with the sustained pulse time. For the common nozzle, the cleaning effect is influenced by the nozzle diameter and the jet distance. The optimum jet distance declines with the increase of nozzle diameter. Compared with the common nozzle, the pulse-jet cleaning frequency of the built-in rotator reduced from 11 to 9, the average pulse-jet cleaning interval extended from 4667s to 5402s, the average residual pressure drop decreased from 118.39Pa to 86.04Pa and the average pressure drop reduced from 243.01Pa to 232.52Pa. Despite the average peak dust emission concentration increased from 13.52mg/m3 to 14.34mg/m3, the average dust emission concentration decreased from 2.56mg/m3 to 2.51mg/m3. Therefore, it is proved that the built-in rotator can improve the performance of pleated cartridge filter.

Effects of cleaning mode on the performances of pulse-jet cartridge filter under varying particle sizes

In order to solve the problem of pollution induced by particulate matters, bag filters and pleated cartridge filters have been widely applied to industries. However, the effects of cleaning mode on the performances of filters under varying particle sizes are rarely studied. In this paper, the influence of cleaning mode on the pressure drop and dust emission concentration under varying particle sizes were studied through experiments. The results show that the smaller the particle size is, the faster the pressure drop increases, and the higher the dust emission concentration becomes. In the cleaning process, the smaller the particle size, the greater the residual pressure drop, and the worse the cleaning effect. The cleaning frequency rises with the decrease of particle size under the clean-on-demand (C-D) mode, while the maximum pressure drop grows with the decrease of particle size under the clean-on-time (C-T) mode. For the medium and fine particulate matters, the average dust emission concentration and the average pressure drop under the C-D mode are both slightly larger than those under C-T mode. By comparing the quality indexes under different cleaning modes, it can be found that for medium and fine particulate matters, the use of the C-D mode can ensure more excellent filtration and cleaning performances, while for large particulate matters, the choice between the two modes has very limited influence on the filtration and cleaning performances of pulse-jet cartridge filters.