Scraper Speed Research Articles

Additive manufacturing of high-performance SiO2-Al2O3-K2O (Na2O) ceramic components via binder jetting technology

To resolve issues such as high sintering temperatures and relatively low relative densities and bending strengths of sintered bodies during the preparation of ceramic parts using binder jetting (BJ) additive manufacturing (AM) technology. In this study, high-performance SiO2-Al2O3-K2O (Na2O) ceramics were fabricated using quartz, kaolin, potassium feldspar, and sodium feldspar as raw materials through BJ technology. Initially, the sintering process of the BJ ceramics was studied by adjusting the ratio of potassium feldspar to sodium feldspar and the sintering temperature, which enhanced the relative density and bending strength of the silicate ceramics. Subsequently, using response surface methodology (RSM), the effects of print layer thickness (A), scraper speed (B), and ink volume per unit area (C) on the performance of the ceramics after sintering were investigated. Results indicated that the optimal parameters of the BJ printing process were determined using RSM: A was 250 μm, B was 3.44 mg cm−3, and C was 35 mm s−1. Under these conditions, the sintered ceramics achieved optimal relative densities, closed porosities, and flexural strengths of 89.05 %, 10.85 %, and 69.19 MPa for relative density, closed porosity, and flexural strength, respectively.

Process optimization and modeling of Acer truncatum seed oil deacidification by molecular distillation

Acer truncatum seed oil (ATO) is a unique woody oil resource, but its high acid value resulting from traditional pressing methods falls short of meeting the necessary food standards. In this research, molecular distillation (MD) was employed for the deacidification of ATO and compared with conventional techniques such as alkali refining and solvent extraction. Predictive models for MD deacidification were established through single-factor experiments, orthogonal experimental design (OED), response surface methodology (RSM), and genetic algorithm - back propagation artificial neural network (GA-BP-ANN). Using RSM, a fitting model was obtained with R = 0.999 and Rpre = 0.990 through multiple linear regression. The constructed BP-ANN model (3-9-1) exhibited R = 0.998 and Rpre = 0.998, indicating slightly higher prediction accuracy. With GA-BP-ANN, the optimal process conditions are an evaporator temperature of 190 °C, condensation temperature of 40 °C, scraper speed of 324 rpm, yielding an acid value of refined ATO at 0.240 ± 0.001 mg g−1. Therefore, under appropriate conditions, the MD deacidification method can produce high-quality refined ATO. The developed orthogonal, RSM, and GA-BP-ANN models demonstrated excellent capabilities in optimizing and predicting the MD deacidification process, meeting even the strictest food regulations.

Analysis of the Operating Energy Variables Involved in Mechanized Khoa Production

Significant portion of the total milk production of India has been utilized for the manufacture of the Traditional Indian Dairy Products (TIDP). Khoa based products were traditionally produced in the Indian sub-continent since ancient times. Khoa produced by the mechanized methods can overcome the demerits of traditional manufacturing methods like insufficient use of energy, poor hygiene and sanitation, non-uniform product quality, etc. In the present study, steam jacketed open type hemispherical kettle equipped with spring loaded Teflon edged scraper blade assembly was utilized for the mechanized production of khoa. A standardized mixed milk having (6.0±0.1%) fat and (9.0±0.2%) SNF, was evaporated to the different level of concentration using a batch type vacuum pan. The performance of the mechanized manufacture of khoa was evaluated at different steam pressures (P1= 98.06 kPa, P2=147.1 kPa, P3=171.61 kPa), scraper speed (R1=0.67rps), and different level of milk concentration (C1=35 %TS, C2=40 %TS, C3=45 %TS) for first stage. During the second stage, effect of operating variables on process mechanization were evaluated at different steam pressures (S1= 49.03 kPa and S2= 78.45 kPa) and scraper speed (R2=0.33rps). The primary objective of present study is to carry out thermal and electrical energy analysis associated with mechanized khoa production, which has a significant role in process optimization, scale-up of the operation and to design and fabricate the mechanized system. The overall heat transfer coefficients (U-values) of the mechanized system obtained at various processing parameters ranged from 156.87 to 234.16 W/m2K during khoa manufacturing. The treatment C1 P1 S2 gave the highest U-values for sensible and latent heating. The mean U-values of sensible heating and latent heating were increased with an increase in steam pressure during khoa making in the mechanized system. The mean value of specific steam consumption (kg steam/kg water evaporated) for the optimized operating conditions was 1.950 (kg steam/kg water evaporated) for manufacture of khoa in mechanized system. The total heat losses of mechanized system during manufacture of khoa was 17.15 to 28.02 % at different operating conditions studied. The mean values of electrical power consumption ranged from 141 to 203 Wh under different operating conditions. Considering the energy consumption data, we can narrate that existing system is energy efficient with lower electrical energy consumption and can reduce the labour cost due to mechanization.

Effect of processing by batch type scraped surface heat exchanger (SSHE) onsensory attributes of bottle gourd (Lagenaria siceraria) halwa

The awareness among consumers for healthier and functional food has led to increase in the market size for valued added products. The present study was undertaken to manufacture valued added Indian indigenous dairy product, bottle gourd halwa in a multipurpose batch type SSHE. The performance of the developed SSHE was evaluated at three different steam pressures (1, 1.5 and 2 kg/cm2), scraper speeds (10, 20 and 30 rpm) by keeping batch size constant (5kg) during manufacturing of bottle gourd halwa. The products were evaluated for sensory characteristics with a 9-point Hedonic scale. The overall acceptability of the product was considered on the basis of sensory attributes. The bottle gourd halwa prepared in SSHE at 1kg/cm2 steam pressure and 30 rpm scraper speed (P1S3) had the score of 7.9 for flavour, 7.85 for body and texture and 7.4 for colour & appearance and the highest overall acceptability score (7.72)  as compared to the products prepared at other operating conditions. However, it was not equivalent to control for these attributes.

Thermal and electrical energy analysis of scraped surface heat exchangerduring Kheer making

Kheer is a cereal based sweetened and concentrated milk confection, very well-liked in India. The present investigation was undertaken to study the energy consumption of the developed batch type scraped surface heat exchanger (SSHE) for kheer making. The kheer was prepared by using SSHE at different levels of steam pressure (1.0, 1.5 and 2.0 kg/cm2), scraper speed (10, 20 and 30 rpm) and batch size (10, 15 and 20 kg). The thermal and electrical energy consumptions were determined. The rate of evaporation increased with increase in operating variables. The average rate of evaporation ranged from 11.84 to 25.65 kg water evaporated/h. The specific steam consumption by the SSHE during kheer making ranged between 1.568 and 1.702 kg steam/kg of water evaporated under different operating conditions of the machine. The total heat losses during manufacture of kheer in SSHE ranged from 12.9 to 18.9 %. The electrical power consumption of the machine during manufacturing of kheer varied from 230.1 to 260.5 W.

Optimization and Application of an Efficient and Stable Inhalation Exposure System for Rodents.

Inhalation is a promising and challenging method in pharmaceutical and biological science research. A stable environment is critical in dynamic inhalation administration. However, the establishment of a stable inhalation system is very challenging. Indacaterol glycopyrronium bromide inhalation powder (IM/GP mixed powder) is composed of indacaterol maleate and glycopyrronium bromide powder to treat chronic obstructive pulmonary disease (COPD). The aim of this study is to build suitable inhalation conditions and then to evaluate the pulmonary safety of this drug in Sprague-Dawley(SD) rats. In the research, through the coordination of the atomization flow, air pump flow, and scraper speed, aerosols were stabilized at 200 ± 20% mg/m3, and then rats were nose-only administered with the IM/GP mixed powder, Ultibro, and lactose-magnesium stearate mixed powder at 2.6 mg/kg/day for 14 days and 14 days of recovery period, respectively. After exposure, hematology, inflammatory cytokines in rats bronchoalveolar lavage fluid (BALF) and serum, histopathological examination were performed. Results showed that the stability of powder aerosols can be realized under the atomization generation flow: 10 L/min, sampling flow: 2 L/min, system pumping capacity: 10 L/min and powder scraper speed: 8-10 L/min, and there were no significant adverse effects on body weight, clinic signs, hematology, and pathology in rats. Overall, the results suggested that the IM/GP mixed powder inhalation at the dose of 2.6 mg/kg/d can be reached when the aerosol concentration is within the range of 200 ± 20% mg/m3, and there were no pulmonary toxicity effects in rats.

Characteristics of residence time distribution in a continuous high shear mixer granulation using scraper rotation

Characteristics of residence time distribution (RTD) in a continuous high shear mixer granulation were investigated to promote the development of a continuous manufacturing process in the pharmaceutical industry. A continuous granulator with an impeller and a scraper was utilized. The tracer behavior in the continuous wet granulation was verified in impulse-response experiments with acetaminophen. The RTD of acetaminophen changed depending on the scraper speed (15–50 rpm), and the mean residence time could be adjusted by the scraper speed in the wet granulation. The impact of changes in the liquid-to-solid ratio (0.10–0.20) and the addition of binder were also examined, and the variance of RTD was influenced by both. The degree of axial mixing was quantitatively evaluated with a dimensionless index, the Peclet number (Pe). Higher scraper speed was found to suppress fluctuations of the axial mixing that occurred with changes in the liquid feed. Moreover, the transition of granule size distribution with the change in liquid feed reached a steady state more quickly under the higher scraper speed. These results show that scraper rotation can help to adjust the RTD and the axial mixing, leading to a more robust continuous granulation.

Flow-field analysis of a continuous gas–solid separation fluidized bed equipped with a moving scraper

Continuous gas–solid separation fluidized beds are one of the most widely used practical operation units for the dry separation of coal in China, particularly in Northwest China, and they can effectively promote the efficient and clean utilization of raw coal. In a continuous gas–solid separation fluidized bed, the bed flow field is the concrete manifestation of the fluidization characteristics. However, the complexity of the flow field increases under the action of a moving scraper. In this study, a combination of computational fluid dynamics (CFD) simulations and experimental measurements was used to study the changes in the flow field of a fluidized bed. The results showed that when the scraper moved, the local flow field (mainly characterized by the movement of medium particles) near the scraper was affected not only by the common airflow or bubbles, but also by the lateral driving force of the scraper. When the scraper speed was vl<6.0cm/s, it reduced the frequency of the formation of large bubbles and alleviated the random fluctuation of the nearby particle collision stress signals, which improved the fluidization stability of the bed. Additionally, the movement of the scraper affected the global flow field. The flow field shifted to the right near the scraper, with the direction of the scraper movement, while the flow field exhibited a leftward trend on the surface of the bed, accompanied by some vortices, in the middle and lower parts of the bed. Additionally, the critical height of the area, directly affected by the scraper, increased from 52 to 54mm with an increase in its operating speed from vl=2.96cm/s to vl=4.44cm/s, respectively. This provides a theoretical basis for further understanding the hydrodynamic characteristics of fluidized beds.

Evaluation and prediction of overall heat transfer coefficient of Scraped surface heat exchanger during kheer making

Scraped surface heat exchanger (SSHE) is one of the adaptable equipments for products which are viscous, containing suspended constituents which tend to deposit and form layer on the heat transfer surface. The study was undertaken to evaluate and predict the overall heat transfer coefficient (U) of SSHE for making kheer. The performance of the developed SSHE was evaluated at three different steam pressures (1.0, 1.5 and 2.0 kg/cm2), scraper speeds (10, 20 and 30 rpm) and batch sizes (10, 15 and 20 kg) during kheer making. There was significant increase in the U-value with increase in operating steam pressures, batch sizes and scraper speeds. The quality of the kheer prepared in SSHE at optimized condition (i.e. 1 kg/cm2 steam pressure, 20 kg batch size and 30 rpm scraper speed) was found superior in terms of the sensory attributes, having U-value of 1197.40 W/m2K, steam side heat transfer coefficient (ho) was 8634.60 W/m2K and product side heat transfer coefficient (hi) was 2251.53 W/m2K. The regression equation was developed for predicting the U-value.

Control of residence time of pharmaceutical powder in a continuous mixer with impeller and scraper.

The control of residence time in a powder mixing process was investigated toward the development of a continuous pharmaceutical manufacturing system. A powder mixer equipped with an impeller and a scraper, which was designed for a continuous granulation machine, was used. The mixing homogeneity and dynamic behavior of the powder in the mixer were investigated by using a tracer, acetaminophen, in impulse- and step-response experiments. The homogeneity of the mixture was guaranteed by the high rotation speed of the impeller, independent of the speed of the scraper. The mean residence time of the powder was controlled by changing the scraper speed. The hold-up weight in the mixer was also changed by the scraper speed. In the measurement of the hold-up weight, the scraper speed also affected the powder filling density. These results confirmed that the scraper equipped in the mixer transported powder towards the exit of the mixer, and that both the scraper's rotation speed and its shape are key parameters for flexibly controlling the residence time of powder in the mixer. These experimental results can provide useful information for adjusting the residence time in order to optimize conditions for the corresponding continuous granulation system.

Investigating the performance of ice slurry system and the growth of ice crystals using seawater

This study investigates ice slurry systems, their transport characteristics, and seawater ice crystal formation through microscopy. Here, the salinity of seawater was set to vary between 10 and 30 ppt (part per thousand) and was used to form ice slurries. Pump flow rates were adjusted to be in between 5 and 30 L/min, while the scraper speed was set to vary at 350-550 RPM in positive correlation with the speed. It was discovered that ice slurries generated with a salinity of 10 ppt seawater had a significantly positive effect on ice production rate. Additionally, such ice slurries resulted in an intended reduction on the formation time of the ice slurries, while the flow and stirring rates were maintained between 10 to 15 L/min and 400 to 450 RPM, respectively. Additionally, the transport characteristics of the ice slurry were affected in terms of the increase in flow rate, salinity, and ice mass fraction. As an interesting threshold, the diameter of the ice crystals increased as storage time increased, and seawater concentration decreased, which was followed by agglomeration and the Ostwald ripening phenomenon. For cold storage applications, therefore, a low salinity of seawater (10-20 ppt) and 60 % ice mass fraction were recommended to deliver the best intended performance in an ice slurry system.

Performance Evaluation of Three-Stage SSHE for Continuous Manufacturing of Burfi

Burfi was manufactured in three-stage scraped surface heat exchanger by adding sugar directly into preheated milk by varying scraper speed in all three stages with different steam pressure in all three stages. The performance evaluation of the machine was evaluated during continuous mechanized manufacturing of Burfi. The average overall heat transfer coefficient were 1600, 950, and 410 W/m2 K for first, the second and third stage of TFSSHE, respectively. The specific steam consumption was found out to be 1.12 to 0.93 kg steam per kg of milk processed with mean value of 1 kg steam per kg of milk processed. The electricity consumption was found out to be 6.0 to 8.34 kWh per 1000 kg of milk processed with a mean value of 6.83 kWh per 1000 kg of milk processed. The sensory evaluation score of the burfi manufactured in the SSHE was obtained 20.6 out of a total of 25.

Optimization of Scraped Surface Heat Exchanger Process Parameters for Manufacture of Bottle Gourd Halwa

The present investigation has been aimed to study the effect of various process parameters of scraped surface heat exchanger (SSHE) on the sensory characteristics of fresh bottle gourd halwa. The horizontal SSHE designed and fabricated at the Institute was used to manufacture bottle gourd halwa. The freshly prepared bottle gourd halwa samples were analyzed for their sensory characteristics prepared at different scraper speed (R1, R2, R3 at 20, 30 and 40 rpm respectively), and operating steam pressure (G1, G2, G3 at 0.75, 1.0 and 1.5 kg/cm2 respectively) for varying batch size (B1, B2, B3 of 2, 3 and 4 kg respectively). A uniform quality product with respect to flavor, body and texture, color and appearance, and overall acceptability (sensory scoring) was obtained employing the combination of treatments G2B3S2 among the rest of combinations. Cost analysis of bottle gourd halwa prepared in SSHE under operating condition G2B3S2 was computed at `150.35; the raw materials cost and operating cost was `116.82 and `33.53, respectively.

Molecular Distillation-Induced Deacidification of Soybean Oil Isolated by Enzyme-Assisted Aqueous Extraction: Effect of Distillation Parameters

Soybean oil isolated by enzyme-assisted aqueous extraction (EAE) was subjected to molecular distillation-induced deacidification, and the effects of evaporator temperature, scraper speed, and feed flow rate on oil quality (acid value, color, peroxide value, p-anisidine value, tocopherol content, and fatty acid content) were evaluated to determine the suitable deacidification conditions. Fatty acid content was largely unaffected by evaporator temperature and scraper speed, while an increase of these parameters decreased tocopherol content as well as acid, peroxide, and p-anisidine values and resulted in Lovibond color deepening. The increase of feed flow rate had an opposite effect on the above quality indices. As a result, molecular distillation of EAE-produced soybean oil under suitable conditions (evaporator temperature = 180 °C, scraper speed = 220 rpm, feed flow rate = 4 mL/min) was found to afford a high-quality deacidified product in an environmentally friendly way.

Investigations into ice scaling during eutectic freeze crystallization of brine streams at low scraper speeds and high supersaturation

Eutectic Freeze Crystallization (EFC) is a potentially cost-effective method to treat reverse osmosis (RO) brines, through the simultaneous crystallization of ice and salt. A major operational challenge, limiting the implementation of EFC in industry, is the formation of an ice scale layer on heat exchanger surfaces. This research determined the influence of the heat transfer driving force, hydrodynamics and brine composition on the severity of ice scaling during continuous EFC of a Na2SO4-H2O system. Experiments were conducted in a hybrid crystallizer-separator with a scraped 2 L crystallization zone. The research focussed on high heat transfer driving forces and slow scraping rates. A unique induction time for scale formation was observed for each set of process conditions. The induction time increased with the increase in scraper speed and decreased as the heat transfer driving force increased. The increase in induction time at higher rotational Reynolds number was attributed to faster distribution of supersaturation, as the flow regime became more turbulent, and more efficient scraping of ice off the wall. The scaling potential decreased as the magma density increased until a certain threshold was reached where it increased again due to the solids impeding effective mixing and heat transfer. Scaling tendencies were reduced during crystallization of multi-component brine streams as compared to binary streams.

Studies on fluidization characteristics of a continuous gas-solid fluidized bed with dynamic scrapers

Scrapers are important inner components in continuous fluidized beds in the state where they are most commonly used industry. Dynamic scrapers have significant effects on fluidization characteristics. A lab-scale continuous air dense medium fluidized bed (CADMFB) was designed, and the influences of operational parameters were studied. Moving scrapers lead to velocity gradients in the horizontal direction among magnetite particles in different bed heights, which assisted in loosening of the dense medium bed. Hence, bed pressure drop and minimum fluidization airflow rate were lower than those in beds with static scrapers. If the scraper velocity is kept constant, minimum fluidization airflow rate increases with increasing scraper distance. But the ratio of standard deviation to average bed pressure drop increases with the increase in the scraper distance, which indicates a decrease in bed stability. Minimum fluidization airflow rates also increased with increasing scraper velocities, but a fast scraper speed may also cause bed pressure fluctuations. Dynamic scrapers can inhibit the generation of big gas bubbles. Optimum scraper velocities for various scraper distances can be calculated by v>Lg0.6π0.21.43Q0.2. Results indicate that 50 mm was the ideal scraper distance, and the optimum scraper velocity was about 0.35 m/s. Results also show that fluidization in boundary zones between dynamic scrapers and static sidewalls was worse than that of middle zones of CADMFB.

Вплив відхилення напруги на технологічні та енергетичні характеристики скреперних установок для прибирання гною

The voltage deviation from the normalized values has negative consequences, among which the most significant are the violation of the normal course of technological processes, simple enterprises and the issue of poor quality products, shortening the life of electrical equipment, increase in electricity losses in the elements of the power supply system. Economic losses, caused by low quality of electric energy, have two components: electromagnetic and technological. The electromagnetic component is determined mainly by the loss of active power and the change in the life of the electrical equipment. The technological component of losses is due to the influence of the quality of electricity on the productivity of technological installations and the cost of production. The purpose of the study is to determine the effect of voltage deviation on the technological and energy characteristics of scraper plants for cleaning manure. Due to the deviation of the voltage, the angular velocity of the motor changes, which, in turn, causes the change in the technological characteristics of the working machines. For steady-state installations, the change in angular velocity is inversely proportional to the square of the voltage deviation, and the output is directly proportional to the angular velocity of the electric motor .. When voltage decreases, the scraper speed and the performance of the scraper unit for manure removal increase indirectly. The law of the change of these values is determined by the law of changing the angular velocity of the engine when the voltage changes. The voltage deviation causes the loss of active power in the electric drive of the scraper unit. Variable power losses in the electric drive of the scraper installation are inversely proportional to the square of the voltage. When voltage increases, they decrease in comparison with nominal, and at decrease - increase Continuous power losses, on the contrary, when voltage decreases, decrease, and with increase - increase. Since permanent losses of power are less than variable losses, when the voltage decreases, the loss in the engine increases, and at increase - somewhat reduced. As a result of the conducted research it was established that when the voltage decreases by 20%, the efficiency of the scraper installation decreases by 4%, and the specific power consumption increases by 11%. Key words: scraper installation, electric drive, voltage deviation, productivity, scraper speed, technological characteristic, power characteristic

Experimental Study on Mechanical Vapor Compression Treatment of Landfill Leachate

. This essay dealt with the treatment of landfill leachate by means of mechanical vapor compression. The influence of different feed rate, feed temperature and scraper speed was studied on the heat transfer coefficient of wiped film evaporator. The experimental results showed that the larger the feed rate, the smaller the heat transfer coefficient. The feed temperature and the scraper speed had the optimal value. At this time, the heat transfer coefficient reached the maximum value.

Effect of scraper movement on the separation performance of air dense medium fluidized bed

Experimental studies on the influence of scraper movement on the fluidization of air dense-medium fluidized bed (ADMFB) have been conducted. The maximum bed pressure drop is about 3% when the scraper speed changes from 0 to 0.5m/s. The minimum fluidized velocity Umf decreases as the scraper speed increases. At the same time, the bed density only declines by 3.7%, and the density standard deviation decreases significantly which is mainly caused by the horizontal motion of the medium. The separation tests indicated that the most appropriate scraper speed is between 0.1m/s and 0.3m/s and it was reasonable to move the scraper at the appropriate rate to get the better separation performance.

Optimization of the Scraper Speed and Improvement of the Refrigerant Path for the Evaporator of the Soft Ice Cream Machine

Optimization of the Scraper Speed and Improvement of the Refrigerant Path for the Evaporator of the Soft Ice Cream Machine