Stainless Steel Belt Research Articles

Before and After: Evaluation of Microbial and Organic Loads in Produce Handling and Packing Operations with Diverse Cleaning and Sanitizing Procedures

Inadequate cleaning and/or sanitation (C/S) of food contact surfaces (FCSs) has been frequently reported during Produce Safety Rule inspections; however, limited data are available evaluating the effectiveness of C/S processes in produce operations. Different C/S practices were evaluated in four fresh produce operations for their efficacy in reducing microbial and organic loads on various FCSs. Microbial (aerobic plate counts; APC) and organic (ATP) loads were quantified during production, after cleaning, and after sanitizing, if applicable. Operations included: a berry packinghouse (BerryPK; wet cleaning), a blueberry harvest contractor (BerryHC; cleaning + sanitizing, C+S), and two mixed vegetable packinghouses (MixedV1; C+S, and MixedV2; rinsing + sanitizing, R+S). Following wet cleaning, significant reductions in APCs (p < 0.05) were seen on high-density polyethylene (HDPE) storage trays (n = 50) in BerryPK (3.1 ± 0.9 to 2.5 ± 0.7 log CFU/100 cm2). In BerryHC, a greater reduction in APCs was seen on HDPE harvest buckets (n = 25) following C+S (3.8 ± 0.5 to 1.1 ± 0.4 log CFU/100 cm2), compared to wet cleaning only in BerryPK. Stainless steel and conveyor belt FCSs (n = 16) in MixedV1 were sampled, and a significant reduction in APCs (p < 0.05) was observed when comparing in-use (4.8 ± 1.3 log CFU/100 cm2) to post-C+S (3.9 ± 0.7 log CFU/100 cm2). When similar FCSs (n = 17) were sampled in MixedV2, R+S also led to significant reduction in APCs (3.3 ± 0.6 to 1.9 ± 0.6 log CFU/100 cm2) (p < 0.05). ATP testing in fresh produce settings yielded inconsistent results, with no correlation between organic and bacterial loads detected during production (R2 = 0.00) across four operations, and weak correlations observed after cleaning (R2 = 0.18) and after sanitation (R2 = 0.33). The results from this study provide the foundational basis for future research on practical and effective C/S methods tailored to the produce industry.

DEVELOPMENT OF A PARALLEL GRIPPER WITH AN EXTENSION NAIL MECHANISM USING A METAL BELT

Aiming to expand the range of applications for parallel grippers, we propose an extension nail mechanism that can be mounted on a parallel gripper. We also propose an extension nail mechanism comprising a stainless steel belt, two transport belts, a triangular nail, and a drive unit. The triangular nail is connected to one end of the stainless steel belt, and the drive unit is connected near the other end. We achieve smooth sliding of the nails underneath objects by arranging the transport belts on either side of the stainless steel belt. By elastically winding one end of the stainless steel belt and each of the transport belts, the nail mechanism can be miniaturized while achieving large expansion and contraction. We achieve stable grasping operations by using the extension nail mechanism of the parallel gripper in accordance with the flexibility of the object.

Transfer efficacy of Escherichia coli O157:H7 between surfaces of green mature tomatoes and common food processing materials

The objectives of this study were: a) to evaluate E. coli O157:H7 survival on green mature tomatoes and squares of common food processing materials – stainless steel, plastic (HDPE), and vinyl conveyor belt (PVC) – post-drying, stored at 25 ºC in the humidified environment for four days; b) to determine pathogen transfer rates (wet, 90 minutes, or 24-hours drying post-inoculation), from inoculated tomato surfaces to uninoculated steel, plastic, and vinyl conveyor belt squares and conversely. It was shown that E. coli O157:H7 did not survive well on the surface of tomatoes, resulting in a decline from 5.3 log10 CFU.mL-1 90 minutes post-drying to 1.4 log10 CFU.mL-1 on day 4. Similarly, the pathogen did not survive well on the surface of food processing squares, with numbers declining over 4 days from 4.04, 4.44, and 4.19 CFU.mL-1 of rinsate 90 minutes squares post-drying to 0.72, 0.50, 0.83 log10 CFU.mL-1, which is close to the detection limit, for the steel, vinyl belt, and plastic, respectively. Successful cross-contamination between tomatoes and food processing surfaces was achieved during wet transfer; while transfer after 90 minutes inoculum post-drying and 24 hours were less successful. This can be explained by both lack of liquid media with suspended bacteria for transfer and fast pathogen die-off after desiccation. Dry transfers, as shown by the percentage of “positive” for pathogen presence tomatoes and squares, as well as bacterial counts, were more successful from tomatoes to squares, but not conversely. Special concern raised vinyl conveyor belt, where the surface picked up the most pathogen cells from the surface of tomatoes, resulting in 100% positive during 90 minute-dry transfers, followed by plastic (66.7% positive) and steel (55.6% positive). To summarize, we presented data on the possibility of cross-contamination between mature green tomatoes and common food processing surfaces, which may be interesting for the processors for risk evaluation.

Air Entrainment and Surface Fluctuations in a Turbulent Ship Hull Boundary Layer

Air entrainment due to turbulence in a free-surface boundary layer shear flow created by a horizontally moving vertical surface-piercing wall is studied through experiments and direct numerical simulations (DNS). In the experiments, the moving wall is created by a laboratory-scale device composed of a surface-piercing stainless steel belt that travels in a loop around two vertical rollers; one length of the belt between the rollers simulates the moving wall. The belt accelerates suddenly from rest until reaching constant speed and creates a temporally evolving boundary layer analogous to the spatially evolving boundary layer that would exist along a surface-piercing towed flat plate. We report cinematic laser-induced fluorescence measurements of water surface profile histories, cinematic observations and measurements of air entrainment events, and air bubble size distributions and motions. To complement the experiments, DNS of the temporally evolving turbulent boundary layer were conducted, considering both the air and water phases. Because of cost considerations, only a portion of the belt was simulated at a lower Reynolds number, keeping the Froude number, however, at the same levels as in the experiments. The results of the experiments and DNS are found to be in qualitative agreement and are used synergistically to explore the physics of the air entrainment process; quantitative agreement is not to be expected given the differences in setup and Reynolds numbers. In the experiments and DNS, the free-surface motion is found to consist of a region near the belt with fast-moving uncorrelated large-amplitude ripples and an outer region of small-amplitude propagating waves. Entrainment events similar to plunging breaking waves are found in the experiments, and these and other entrainment mechanisms are examined in detail in the DNS. The spatial distributions of bubble numbers and velocities are reported along with their diameter distributions.

Air Entrainment and Surface Fluctuations in a Turbulent Ship Hull Boundary Layer

The air entrainment due to the turbulence in a free surface boundary layer shear flow created by a horizontally moving vertical surface-piercing wall is studied through experiments and direct numerical simulations. In the experiments, a laboratory-scale device was built that utilizes a surface-piercing stainless steel belt that travels in a loop around two vertical rollers, with one length of the belt between the rollers acting as a horizontally-moving flat wall. To complement the experiments, Direct Numerical Simulations (DNS) of the two-phase boundary layer problem were carried out with the domain including a streamwise belt section simulated with periodic boundary conditions. Cinematic Laser-Induced Fluorescence (LIF) measurements of water surface profiles in two vertical planes oriented parallel to the belt surface (wall-parallel profiles) are presented and compared to previous measurements of profiles in a vertical plane oriented normal to the belt surface (wall-normal profiles). Additionally, photographic observations of air entrainment and measurements of air bubble size distributions and motions are reported herein. The bubble entrainment mechanisms are studied in detail through the results obtained by the DNS simulations. Free surface features resembling breaking waves and traveling parallel to the belt are observed in the wall-parallel LIF movies. These breaking events are thought to be one of the mechanisms by which the air is entrained into the underlying flow. The bubble size distribution is found to have a characteristic break in slope, similar to the Hinze scale previously observed in breaking waves. Finally, several entrainment mechanisms are found in the simulations and their prevalence in the free surface boundary layer is assessed.

不锈钢化学着色颜色控制技术研究

本文通过CS350电化学工作站测试了不锈钢着色的电位–时间曲线，分别比较了控制430不锈钢片着色的：时间一致、电位一致、电位差一致和达到终点电位后至电位稳定等四种情况下的彩色不锈钢颜色的重现性。结果表明：控制时间一致、电位一致、电位差一致，均难保证彩色不锈钢颜色的良好重现性，而当着色电位达到稳定的终点电位时，彩色不锈钢颜色的重现性很好。这种控制不锈钢着色达稳定的终点电位法，可望成为不锈钢连续卷带着色颜色控制的较好方法。In this article, the potential vs time curves during the coloring process of the 430 stainless steel were tested by CS350 electrochemical workstation. The color reproduction of the colored stainless steel was controlled by same coloring time, same coloring potential, same potential difference and being colored to stable end potential. The results show that, when controlled by same coloring time, same coloring potential and same potential difference, it is difficult to guarantee good color reproducibility of the colored stainless steel. However the color reproducibility of colored stainless steel controlled by reaching the stable end potential is excellent. This stable end coloring potential method for controlling the coloring of stainless steel is a promising method which can be used in continuous coloring of stainless steel belt.

Service Life Extension of Stainless Steel Wire Mesh Belts for Sintering Furnaces

The service life of stainless steel wire mesh belts in sintering furnaces is limited, because material deterioration results in wire fracture. A newly developed humidification system establishes a furnace atmosphere that maintains a protective oxide scale on the belt surface throughout the sintering process and at the same time creates an environment that is reducing to the sintered metal compact. This work includes thermodynamic calculations of the furnace atmosphere dew points that satisfy these oxidation / reduction criteria. Scanning Electron Microscopy, combined with Energy-dispersive X-ray Analysis, and mechanical testing methods have been used to compare belts that have undergone the same length of service in a nitrogen-hydrogen atmosphere and in an atmosphere that was modified using the newly developed humidification method. The material examinations have revealed that the new humidification system significantly extends the service life of stainless steel belts.

Attachment ofSalmonella serovars andListeria monocytogenes to stainless steel and plastic conveyor belts

In poultry industry, cross-contamination due to processing equipment and contact surfaces is very common. This study examined the extent of bacterial attachment to 6 different types and design of conveyor belts: stainless steel-single loop, stainless steel-balance weave, polyurethane with mono-polyester fabric, acetal, polypropylene mesh top, and polypropylene. Clean conveyor belts were immersed separately in either a cocktail of Salmonella serovars (Salmonella Typhimurium and Salmonella Enteritidis) or Listeria monocytogenes strains (Scott A, Brie 1, ATCC 6744) for 1 h at room temperature. Soiled conveyor chips were dipped in poultry rinses contaminated with Salmonella or Listeria cocktail and incubated at 10°C for 48 h. The polyurethane with mono-polyester fabric conveyor belt and chip exhibited a higher (P<0.05) mean number of attached Salmonella serovars (clean: 1.6 to 3.6 cfu/cm2; soiled: 0.8 to 2.4 cfu/cm2) and L. monocytogenes (clean: 4.0 to 4.3 cfu/cm2; soiled: 0.3 to 2.1 cfu/cm2) in both clean and soiled conditions. The stainless steel conveyor belt attached a lower (P<0.05) number of Salmonella serovars (clean: 0 to 2.6 cfu/cm2; soiled: 0.4 to 1.3 cfu/cm2) and L. monocytogenes (clean: 0.4 to 2.9 cfu/cm2; soiled: 0 to 0.7 cfu/cm2) than the polymeric materials, indicating weaker adhesion properties. Plastic conveyor belts exhibited stronger bacterial adhesion compared with stainless steel. The result suggests the importance of selecting the design and finishes of conveyor belt materials that are most resistant to bacterial attachment.

Hydrogen Embrittlement on High-Speed Stainless Steel Belts Used for Tin Plating Chip Lead Frame

The 300 series stainless steels generally exhibit good corrosion resistance in common use. However, a premature fracture event caused by hydrogen embrittlement was encountered on 300 series stainless steels which was used as belt hanging chips in a tin plating process for the chip lead frame. The cause of the fracture was carefully studied. A metallurgical microscope and photoelectric direct reading spectrometer were used to examine the metallographic structures and chemical compositions of the matrix material. A scanning electron microscope and energy disperse spectroscope were also applied to analyze the micro morphologies and micro-area composition of the fracture. Meanwhile, the chemistry and hydrogen content of the process media were inspected by ion chromatography and hydrogen analyzer. In addition, the finite element method was employed to simulate the effect on the belt from the service conditions. The analysis results revealed that the unqualified material selection, the aggressive media, and the inappropriate technological parameters were the main causes of the failure. Furthermore, the mechanisms of hydrogen embrittlement were discussed, and countermeasures and suggestions were put forward.

Failure analysis of belt/roll tribological pair used for the production of eucalypt fiber panels

The premature failure of a large agglomeration machine used for the annual production of 360,000 m 3 of eucalypt fiber panels was investigated to identify the nucleation and growth mechanisms of cracking in PH stainless steel belts (126 m × 2.9 m × 3.0 mm). These belts are used to compress a cushion composed of eucalyptus fibers and glue, being the pressure transmitted from the pistons by the action of numerous case-hardening steel rolls. Examination of the belt working interfaces (belt/rolls and belt/eucalypt fibers) indicated that the main cracking was nucleated on the belt/roll interface and that there is a clear relationship between the crack nucleation and the presence of superficial irregularities, which were observed on the belt/roll working surface. Used rolls showed the presence of perimetric wear marks and 2 μm silicon-rich encrusted particles (identified as silicon carbide). Lubricant residues contained the presence of helicoidal wires, which were originated by the release of the stainless steel cleaning brush bristles, and 15 μm diameter metallic particles, which were generated by material detachment of the belt. The presence of foreign particles on the tribological interface contributed to an increase of the shear stresses at the surfaces and, consequently, the number of the contact fatigue crack nucleation sites in the belt/roll tribo-interface. The cracking was originated on the belt/roll interface of the stainless steel belt by a mixed rolling/slip contact fatigue mechanism, which promoted spalling and further nucleation and growth of conventional fatigue cracks. Finally, the system lubrication efficiency and the cleaning procedure should be optimised in order to increase the life expectancy of the belt.

Inactivation of Listeria monocytogenes/Flavobacterium spp. biofilms using chlorine: impact of substrate, pH, time and concentration.

To determine the effect of chlorine on mixed bacterial biofilms on stainless steel (SS) and conveyor belt surfaces. Biofilms were exposed to pH-adjusted (6.5) and non-pH-adjusted solutions of chlorine (200, 400 and 600 ppm) for either 2, 10 or 20 min and survivors enumerated. There were significant differences in cell death relating to chlorine concentration and exposure time for the cells attached to the SS, with solutions adjusted to pH 6.5 being more effective at reducing numbers. In contrast, on conveyor belt surfaces cell numbers decreased by less than two logs after 20 min regardless of treatment. Chlorine effectiveness is dependent on its concentration, solution pH, exposure time, the nature of the surface and the microbial species present. SIGNIFICANCE AND IMPACT OF THE STUDY the interests of food safety it is important that sanitizer users are aware of the conditions that effect their performance.

Transfer of microorganisms, including Listeria monocytogenes, from various materials to beef.

The quantity of microorganisms that may be transferred to a food that comes into contact with a contaminated surface depends on the density of microorganisms on the surface and on the attachment strengths of the microorganisms on the materials. We made repeated contacts between pieces of meat and various surfaces (stainless steel and conveyor belt materials [polyvinyl chloride and polyurethane]), which were conditioned with meat exudate and then were contaminated with Listeria monocytogenes, Staphylococcus sciuri, Pseudomonas putida, or Comamonas sp. Attachment strengths were assessed by the slopes of the two-phase curves obtained by plotting the logarithm of the number of microorganisms transferred against the order number of the contact. These curves were also used to estimate the microbial population on the surface by using the equation of A. Veulemans, E. Jacqmain, and D. Jacqmain (Rev. Ferment. Ind. Aliment. 25:58-65, 1970). The biofilms were characterized according to their physicochemical surface properties and structures. Their exopolysaccharide-producing capacities were assessed from biofilms grown on polystyrene. The L. monocytogenes biofilms attached more strongly to polymers than did the other strains, and attachment strength proved to be weaker on stainless steel than on the two polymers. However, in most cases, it was the population of the biofilms that had the strongest influence on the total number of CFU detached. Although attachment strengths were weaker on stainless steel, this material, carrying a smaller population of bacteria, had a weaker contaminating capacity. In most cases the equation of Veulemans et al. revealed more bacteria than did swabbing the biofilms, and it provided a better assessment of the contaminating potential of the polymeric materials studied here.

Test of the EURATOM LCT coil (NbTi conductor) with forced flow He II cooling

The EURATOM LCT coil, a D shaped NbTi coil, was tested in the TOSKA facility at Forschungszentrum Karlsruhe with pressurized forced flow He II cooling. A suitable cryogenic system based on an existing 1.8 K He II 300 W liquifier was designed for cooling the coil by pressurized forced flow He II circulated by pumps across heat exchangers immersed in a He II bath. Three types of pumps (piston, centrifugal, thermomechanical) were used. The cryogenic system worked well under usual operation and fault conditions. No significant differences were found between He I and He II forced flow cooling. The D-shaped coil was reinforced by stainless steel belts keeping the D shape in single coil operation mode. No backlash was found between the coil and its reinforcement structure in agreement with predictions of the finite element analysis. The coil achieved ∼11 T as predicted from single strand measurements and previous tests in the frame of the Large Coil Programme. The results are an encouraging step in using this technology in large superconducting magnet systems for magnetic confinement in fusion research.

Comparison of Solvent Elimination Systems for the Analysis of Dyes and Pesticides by High-Performance Liquid Chromatography Fourier Transform Infrared Spectrometry

Two systems have been compared for the on-line production of infrared spectra of compounds separated by high-performance liquid chromatography (HPLC). System 1 had a thermospray interface to evaporate the mobile-phase solvents and deposit the solutes onto a moving stainless steel belt, for direct analysis by reflection–absorption IR spectrometry. In system 2, the column effluent was split 1:6 and pumped through an ultrasonic nebulizer. The spray was desolvated at reduced pressure in a heated transfer tube and the solutes deposited onto a ZnSe window for direct analysis by transmission IR spectrometry. When system 1 was used for the analysis of reactive dyes, eluent containing ammonium acetate caused a large background spectrum, as a film of unknown composition was formed on the surface of the stainless steel belt. An alternative procedure, without ammonium acetate, was developed with a mixed-mode column containing C18 and cation exchange particles, but variable retention times were obtained. System 2 could be used satisfactorily with eluents containing ammonium acetate, and it produced dye spectra of better resolution than those obtained with system 1. When the dyes were examined under a microscope, the material on the ZnSe window was more uniform and more evenly distributed on a narrower track than were the deposits on the stainless steel belt. Consequently, the peak shape of the IR chromatograms was better with system 2, and a lower detection limit was achieved for reactive blue 74 (9 ng). When mixtures of the pesticides metolcarb and carbofuran were analyzed, a thermospray temperature of 196 °C was required to desolvate the effluent from the HPLC column in system 1. At this temperature, thermal degradation of the pesticides occurred, and no spectrum was recorded from the belt surface. However, with system 2, deposition of the pesticides was achieved at 90 °C, without degradation, and IR spectra/chromatograms were obtained. Overall, the study showed that the infrared chromatograph (IRC) was the more efficient and flexible interface for HPLC Fourier transform infrared (FT-IR) spectrometry.

Coupling of High-Performance Liquid Chromatography to Fourier Transform Infrared Spectrometry Using a Heated Gas Flow Modified Thermospray

A thermospray was modified and used to couple high-performance liquid chromatography (HPLC) to Fourier-transform infrared (FTIR) spectrometry, which was applicable to both normal- and reversed-phase HPLC. Column effluents from the HPLC system were desolvated by thermospray and solutes were deposited as individual spots on a moving stainless-steel belt (0.025 mm thickness×13 mm width) substrate, which continuously transferred the analytes into the diffuse reflectance (DRIFT) accessory of the FTIR, enabling identification of deposited solutes by measurement of the IR spectrum. The thermospray temperature and thermospray height were shown to influence the deposition of solutes. By use of a heated external nitrogen gas flow, desolvation of the reversed-phase HPLC eluents was improved and reduction of power supply in the thermospray capillary was achieved. Thus lower thermospray capillary temperatures could be used. The IR spectra of the separated individual components showed good agreement of the spectral features to those of standard FTIR spectra and no thermal degradation was found to occur.

Evaluation of gel permeation chromatography to Fourier transform infrared spectrometric detection using a modified thermospray for analysis of polystyrene samples

A heated gas flow modified thermospray was used to couple gel permeation chromatography (GPC) to Fourier transform infrared spectrometry (FTIR) for the analysis of the standard polystyrene samples. Effluents from the GPC column were evaporated and the solutes were deposited as a series of spots on the surface of a moving stainless steel belt (0.025 mm thickness × 13 mm width). The belt continuously transferred the spots into the diffuse reflectance (DRIFT) accessory of the FTIR spectrometer, enabling identification of the deposited solutes by measurement of the diffuse reflectance IR spectrum. The IR spectra of the separated components showed excellent agreement of the spectral features to those of standard FTIR spectra and no thermal degradation was observed.

Effect of Cleaners and Sanitizers on Listeria monocytogenes Attached to Product Contact Surfaces

A variety of chemical cleaning and sanitizing compounds were evaluated for their ability to remove and/or inactivate surface adherent Listeria monocytogenes. Adherent cells were obtained by incubating 1-cm2 chips of stainless steel or plastic conveyor belts with a multistrain cocktail of L. monocytogenes for 24 h at 25°C. Resistance of adherent cells to sanitizers was dependent upon the surface studied, being greatest on polyester/polyurethane followed by polyester and stainless steel. Biofilm removal with cleaners followed the same pattern as sanitizers with the polyester/polyurethane surface being most difficult to clean. Complete biofilm removal and/or inactivation was obtained in many cases where the surface was first cleaned prior to exposure to sanitizer. The data support conventional wisdom in that cleaning must precede sanitizing in order to remove and inactivate microorganisms. Listeria biofilms should be controllable by combining Good Manufacturing Practices with the discipline of a Hazard Analysis Critical Control Point Program.

Basic handling characteristics of wood fuels: Angle of repose, friction against surfaces and tendency to bridge for different assortments

Basic handling characteristics were measured for sawdust, fuel pellets, fuel chips, hog fuel and chunkwood. The aim was to find relations between the basic handling characteristics and easily measurable fuel properties to facilitate the design of feeding systems in heating plants. The angle of repose was 25–55° and increased with the increasing ratio of particle length to thickness and with the increasing content of hooked or long particles. The angle of static friction, 10–40°, was affected more by the kind of surface than the fuel and followed the ascending order: coated plywood, urethane rubber, particle board, stainless steel, concrete and rubber belt conveyor. The tendency to bridge varied considerably and increased with greater content of hooked or long particles, a deeper fuel bed depth over the opening and a higher moisture content. The results indicate that more attention should be paid to the particle shape.

Design of a prototype braking simulator

This paper describes the fundamental design aspets and subsequent development of an elaborate laboratory rig for the accurate measurement of braking system performance. It consists of a fully-instrumented moving stainless steel belt assembly with superimposed texture passing over end pulleys and driven by a variable speed motor. The test wheel forms part of a test axle having torisional strain gauges, a partial drum brake, a slip-ring assembly, a rotational accelerometer unit, a speed sensor and a variable-inertia disc mounted in line. The stimulator permits as many as ten variables to be preset independently prior to or during any test run. The rig can be used to simulate hydroplaning behaviour and to test tread pattern design, and also to evaluate the effectiveness of locked-wheel, constant slip and anti-skid pulsed braking systems. The entire wheel support system can be removed if desired, and a second super-structure substituted to evaluate the high-speed friction and wear behaviour of tread rubber and plastic block samples

High performance magnetic separator for removal of partially magnetic particles from shredded waste

This paper describes a high-performance magnetic separator developed specifically for use with sliding-ramp nonferrous metal separators and designed to remove all particles that are even slightly magnetic from the waste stream. It consists of a magnetic pulley used in combination with an inclined, plane magnet array (similar to the one used in the nonferrous metal separator) and a stainless steel belt. Tests of the separator on shredded municipal waste are described in which the feedrate was varied up to a maximum of 0.8 ton/h.