Mixer Pump Research Articles

Experimental study to make gas bubbles as proxies for oil droplets to test AUV detection of oil plumes

To prepare gas bubble plumes as proxies for oil in autonomous underwater vehicle field experiments, experiments were conducted to compare three microbubble generators, including a dissolved air flotation system, a microbubble diffuser, and a Nikuni Karyu Turbo Mixer (KTM) pump, based on sizes of bubbles and their practicability to be used in field experiments. The sizes of bubbles were measured with a Laser in-situ Scattering and Transmissometry sensor. A Ping360 sonar with a frequency of 750 kHz was tested to assess its ability to capture the generated bubbles. Among the three systems, the KTM pump generated the most stable bubbles with average diameters smaller than 100 µm. Detailed experiments were carried out in a towing tank to further test the size distribution of bubbles generated by the KTM pump. Smaller bubbles were found to remain at higher concentrations at the depth of bubble release, as larger bubbles having higher rise velocities surfaced quickly without staying in the water column. The bubble sizes were cross-validated with the measured residence time of bubbles. The bubble generating system based on the KTM pump is planned to be applied in future field experiments.

Veno-arterial extracorporeal membrane oxygenation for electrical injury induced cardiogenic shock support: a case report

BackgroundHigh voltage electrical injury (HVEI) of more than 1000 V is a potentially devastating form of a multisystem injury associated with high morbidity and mortality.We present the first case of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) as a life saving device for treating a patient with severe cardiogenic shock after a high voltage electrical injury.Case presentationA 26-year-old male sustained HVEI while working with a concrete mixer pump that came in contact with a high voltage cable of 10,000 V. He was immediately disconnected from the mixer pump, underwent cardiopulmonary resuscitation and was transported to the nearest medical centre with severe cardiogenic shock with an ejection fraction (EF) of < 10%.Upon arrival, he was in critical condition, sedated and mechanically ventilated, haemodynamically unstable and supported by intravenous (IV) inotropes after a few events of ventricular fibrillation, with an electrical entry point on the left hand and an exit point located on his right leg. Blood pH was 6.8, PCO2 53 mmHg, PaO2 of 57 mmHg, lactate 8 mmol/L, and Troponin 38,000 ng/dl. The EF was 10% with global severe left ventricular dysfunction. During cardiopulmonary resuscitation (CPR), including cardiac massage and few electrical shocks, he was immediately connected to the VA-ECMO via open right femoral approach with distal arterial leg perfusion.He was treated with IV broad spectrum antibiotics, and high volume fluids to prevent rhabdomyolysis-induced acute kidney injury, total parenteral nutrition, topical silver sulfadiazine cream, and Granuflex for severe electrical burns. He was gradually weaned from inotropes over the next 3 days, during which his clinical condition and bloodwork improved tremendously. His EF gradually increased to 50% and he was weaned from the VA-ECMO, and underwent decannulation 86 h after initialization. He was discharged on day 27 without any sequelae.ConclusionThe VA-ECMO treatment can be a lifesaving device for treating severe cardiogenic shock caused by high voltage electrical injury, and should be considered while treating these “high-mortality risk” patients.

Structural Analysis of Mechanical Seal Holding for Mixer Pumps

A mechanical seal is a device that used to reduce leakage containing pressure or ignoring contamination. Mechanical seal is the device used in centrifugal Pumps, Mixers, Agitators and Compressors to arrest or reduce the leakage. The mechanical seal standard API 682 provides the design guidelines for the seals which are fits below 110mm shaft diameter and 4.2 N/mm2 seal chamber pressure. Any seal more than these parameters required special engineering or guidelines needs from technical service. The main aim is to design the mechanical seal for more than 110mm shaft diameter and more than 4.2 N/mm2 pressure. Since the basic seal components are mostly standardized and already tested than the seal gland connections are seems to be critical for large shaft diameter and high or heavy pressure applications. Hence the stress and deflection of the mechanical seal gland is analyzed based on barrier pressure and seal chamber pressure with the help of Inventor and another critical area is the seal drive arrangements.

3D printed selectable dilution mixer pumps.

In this paper, we demonstrate the ability to 3D print tightly integrated structures with active valves, pumps, and mixers, and we use our compact chip-to-chip interconnects [Gong et al., Lab Chip 18, 639-647 (2018)] to move bulky world-to-chip connections to separate interface chips for both post-print flushing and post-cure device operation. As example devices, we first examine 3D printed pumps, followed by two types of selectable ratio mixer pumps, a linear dilution mixer pump (LDMP) and a parallelized dilution mixer pump (PDMP), which occupy volumes of only and , respectively. The LDMP generates a selectable dilution ratio from a linear set of possibilities, while the PDMP generates a denser set of possible dilutions with a maximum dilution ratio of 1/16. The PDMP also incorporates a new 4-to-1 valve to simultaneously control 4 inlet channels. To characterize LDMP and PDMP operation and performance, we present a new, low-cost video method to directly measure the relative concentration of an absorptive dye on a pixel-by-pixel basis for each video frame. Using this method, we find that 6 periods of the active mixer that forms the core of the LDMP and PDMP are sufficient to fully mix the fluid, and that the generated concentrations track the designed dilution ratios as expected. The LDMP mixes 20 nl per 4.6 s mixer pump period, while the PDMP uses parallelized input pumps to process the same fluid volume with greater choice of dilution ratios in a 3.6 s period.

Design module for the industry design and development of a novel gearless Wankel-like mixer–pump: The Lau–Wan mixer

This paper discusses a case study of a process that provides a holistic design experience by integrating two independent project modules of an undergraduate degree programme. The project proposed by an external party involves the design, manufacture and testing of a scaled prototype for microfluidics applications. The systematic and integrated approach described in the same format as the students’ project report resulted in a novel gearless Wankel-like pump that provided visual results that compare well with the external party’s numerical studies.

Transient thermal analysis for radioactive liquid mixing operations in a large-scaled tank

A transient heat balance model was developed to assess the impact of a Submersible Mixer Pump (SMP) on radioactive liquid temperature during the process of waste mixing and removal for the high-level radioactive materials stored in Savannah River Site (SRS) tanks. The model results will be mainly used to determine the SMP design impacts on the waste tank temperature during operations and to develop a specification for a new SMP design to replace existing long-shaft mixer pumps used during waste removal. The present model was benchmarked against the test data obtained by the tank measurement to examine the quantitative thermal response of the tank and to establish the reference conditions of the operating variables under no SMP operation. The results showed that the model predictions agreed with the test data of the waste temperatures within about 10%.

Analysis of Turbulent Mixing Jets in a Large Scale Tank

Flow evolution models were developed to evaluate the performance of the new advanced design mixer pump for sludge mixing and removal operations with high-velocity liquid jets in one of the large-scale Savannah River Site waste tanks, Tank 18. This paper describes the computational model, the flow measurements used to provide validation data in the region far from the jet nozzle, and the extension of the computational results to real tank conditions through the use of existing sludge suspension data. A computational fluid dynamics approach was used to simulate the sludge removal operations. The models employed a three-dimensional representation of the tank with a two-equation turbulence model. Both the computational approach and the models were validated with onsite test data reported here and literature data. The model was then extended to actual conditions in Tank 18 through a velocity criterion to predict the ability of the new pump design to suspend settled sludge. A qualitative comparison with sludge removal operations in Tank 18 showed a reasonably good comparison with final results subject to significant uncertainties in actual sludge properties.

Slurry pump contract

The Westinghouse Savannah River Company (WSRC) has awarded Curtiss-Wright Electro-Mechanical Corporation (CW-EMD) a $3.7 million contract. The contract is for four waste slurry mixer pumps for use at its Aiken, South Carolina high-level radioactive waste management tank farm. This is a short news story only. Visit www.worldpumps.com for the latest pump industry news

Physicochemical mechanisms controlling the periodic release of flammable gases from hanford tanks

AbstractHanford tanks contain more than 60 million gallons of high‐level wastes produced by decades of extracting plutonium from irradiated uranium fuel. The wastes were concentrated to a thick slurry consistency by evaporation prior to storage to minimize space. The resulting concentrated waste properties introduced unanticipated, detrimental conditions affecting workers' and the public's health and safety and involving the release of potentially flammable gases. The released gases consist primarily of hydrogen, nitrous oxide, and ammonia.Dilution and sluicing were initially proposed to mitigate the flammable gas safety conditions. As a result of evaluations, the mechanisms and conditions that are thought to control the accumulation and spontaneous release of flammable gases were identified and confirmed. The technical rationale was established for developing operational approaches to mitigate the periodic generation of flammable gases in existing tanks and to avoid any reoccurrence of this serious safety problem during future waste management activities. The chemistry of the two highest risk tanks was examined to test the potential for reversing the conditions causing gas buildup and the consequences of sluicing without appropriate chemical conditioning. The identified mechanisms apply equally to the remaining flammable gas tanks at Hanford as well as to other waste tanks in the DOE complex, particularly those at Savannah River. Passive means of mitigating the flammable gas condition require less than 1:1 dilution, and sluicing wastes from tank 106‐C can be accomplished without creating a flammable gas condition.Carbonate equilibria reactions and their effect on aluminum speciation are largely overlooked and provided the key for explaining the episodic release of flammable gases from tank wastes. The reaction of atmospheric carbon dioxide with a sodium hydroxide‐rich waste solution produces carbonate precipitates. More importantly, this reaction lowers the pH of the waste and precipitates aluminum hydroxide as a gel. The wastes contain substantial amounts of complexing agents such as ethylene diamine tetraacidicacid (EDTA), hydroxy ethylene diamine triacidic acid (HEDTA), and their degradation products. These complexing agents stabilize the aluminum hydroxide gel together with chromium, manganese and iron hydroxides, and oxybydroxides under the resulting pH conditions. These complex species may coprecipitate and accumulate as a metastable layer in the middle and lower levels of th tank. The complexed aluminum hydroxide acts as a binding agent trapping other particulates in a microcrystalline mat. Microcrystalline particles such as sodium nitrite provide the structural strength for the mat.Once the gas accumulation below the gel layer achieves a critical buoyancy sufficient to rupture the microcrystalline mat, a gas release event occurs. The cycle of gas buildup and release continues each time the buoyancy of the trapped gas exceeds the hydrostatic pressure and the gels' plasticity modulus. Stokes Law predicts a particle settling rate in the tank of less than 50 days, well within the bistorical periodicity of GREs.Laboratory tests, forming the basis of a recent patent application, verify that large quantities of complexed aluminum hydroxide gel are produced by passing carbon dioxide through simulated waste solutions (Hobl, 1993) equivalent to those found in tank 101‐SY. It was confirmed that a simple adjustment of pH witll redissolve the gel, thereby reducing viscosity and safely facilitating continuous flammable gas release. Additional experiments were undertaken to provide a basis for understanding the role of complexed aluminum hydroxides in the CO2/NaOH/Al(OH)3 (complexing agents)/NaAlO2 system.This article examines a plausible mechanism for the periodic release of flammable gas and considerations for: (1) remediating existing flammable gas tanks through a combination of chemical treatment and mixer pumps; (2) diluting, combining, retrieving, and storing wastes; (3) preventing clogging of transfer lines; (4) sludge and soil washing; and (5) cribs, ponds, basins, and ground‐water cleanup. This study provides a singificant breakthrough for tank waste management by explaining key mechanisms controlling episodic release of flammable gases. The breakthrough provides the bases for removing the tanks classified as flammable gas from the wathclist and has broad operational applications with a potential for billions of dollars in cost savings.

The design and testing of a cryogenic mixer pump

A primary driver of the design of a cryogenic tankage for on-orbit use is the pressure response of the system. It has been proposed to control the fluid state via the use of axial jet mixing. The concept behind this process is to circulate slowly a small amount of the cryogen thereby increasing the interfacial heat transfer, resulting in an isothermal fluid state. If the bulk temperature of the fluid can be known (i.e. the fluid is not thermally stratified), then accurate predictions of the tank pressure can be made, allowing one to determine the number and cycle times of any required pressure reductions. This paper presents the results of a mixer pump development programme for use in liquid nitrogen, liquid hydrogen or liquid helium, and the associated test programme that is to be conducted with this component. The pump requirements, design and operating parameters are presented along with a discussion of the full test programme and expected test results. This component will also allow the elimination of direct ullage venting via its incorporation into an active pressure control system.