China
Africa
Explore chapters and articles related to this topic
Gates and valves
Published in P. Novak, A.I.B. Moffat, C. Nalluri, R. Narayanan, Hydraulic Structures, 2017
P. Novak, A.I.B. Moffat, C. Nalluri, R. Narayanan
High-head (submerged) gates and valves transmit the load to the surrounding structure either directly through their support, e.g. plain (vertical lift), radial, or ring follower gates, or through the shell encasing the valve. The most common valves of the latter type are non-regulating disc (butterfly) valves (turning about a horizontal or vertical axis), cylindrical or sphere (rotary) valves. The main advantage of the latter is the clear water passage when fully open and hence a very low head loss coefficient, but their cost is higher than that of butterfly valves. The most frequently used flow regulating valves in closed pipe systems are sphere valves or pressure reducing valves. For terminal discharge regulation a frequent choice are needle, tube, hollow-jet and particularly Howell–Bunger (fixed-cone dispersion) valves.
Pumps
Published in Paul N. Cheremisinoff, Handbook of Water and Wastewater Treatment Technology, 2019
Valves are classified as either “rotary” or “linear.” In a rotary valve, the ball, disk, or plug is rotated to open or close the flow stream. A linear valve lifts the gate, disk, or plug up or down to open or close the flow stream. Ball valves are rotary. Flow goes through a port in the ball. To shut off flow, the ball is rotated until the port is closed. The ball may be a complete sphere, full ball, as shown in Figure 38, or a partial sphere. Standard port diameters range from 80% of inside pipe diameter to 100%, or full port.
Experimental investigation of operational E-PVC drying conditions on morphological properties of particles in a pilot-scale spray dryer
Published in Chemical Engineering Communications, 2023
Salem Mehrzad, Farzad Jamaati, Masoud Dorfeshan
The latex pump transfers the latex through the filter to the spray dryer. Latex is injected through the two-component spray nozzle into the spray dryer. Plant air is used for the two-component spray nozzle and filtered in the plant air filter and preheated in the plant air heater. The emulsion's water content is vaporized in the spray dryer using filtered and hot air. E-PVC powder and the air are sucked using a drying air blower to the E-PVC powder cyclone separator, where the E-PVC powder is separated from drying air. Filtered drying air escapes through the silencer to the atmosphere. The powder leaves the cyclone separator to the fluidization chute from where it is distributed to the rotary valve. From this rotary valve, the powder is directed to the milling and classifying machine. For the transfer of E-PVC off-spec powder conveying rotary valve is provided, which transfers the E-PVC off-spec powder to the E-PVC off-spec tank. The drying air is induced using the drying air blower. Atmospheric air passes through a fresh air filter. It is conditioned in the air dehumidifier unit and heated with fuel gas in the drying air heater and passes on the spray dryer.
Thermal performance of a single stage double inlet pulse tube refrigerator: experimental investigation and CFD simulation
Published in Experimental Heat Transfer, 2022
K.N. Sai Manoj, S. Anbarasu, S. Ghosh, S.K. Sarangi
Figures 1 and 2 depicts the schematic and experimental test-rig of the DIPTR. The system contains the (a) helium compressor, (b) rotary valve, (c) regenerator, (d) U-tube, (e) cold heat exchanger, (f) pulse tube, (g) hot heat exchanger, (h) orifice valve, (i) reservoir, and (j) double inlet valve. The compressor continuously pressurizes and depressurizes the gas to the DIPTR system through the rotary valve. The rotary valve (frequency of 2 Hz) is operated as an interface in connecting the HP and LP connections between the compressor and regenerator. The regenerator operates as a thermal energy storage device. Stainless steel screen size 250 × 250 mesh/inch and wire diameter 0.04 mm is used as packing material in the regenerator because of the effective heat capacity, LP drop, and low thermal conductivity. To maintain the temperature uniformity, copper mesh screen (size 40 × 40 mesh/inch and wire diameter 0.254 mm) is inserted at every tenth layer of the stainless steel mesh screen. The heat from the HP gas stream is absorbed by the packing material and it is precooled by the LP stream.
Thermo-hydrodynamic analysis and optimal design of a GM cycle cryorefrigerator using response surface methodology and particle swarm optimization
Published in Science and Technology for the Built Environment, 2019
Debashis Panda, Ashok Kumar Satapathy, Sunil Kr Sarangi
The computational domain and the grid point structure is shown in Figure 1. Computational domain consists of a “high pressure valve” (HPV), “low pressure valve” (LPV), a “regenerator” (REG), a “cold heat exchanger” (CHX), an “expansion chamber” (EC), and a “displacer” (DIS) from the left end (of Figure 1). Both HPV and LPV constitute the rotary valve (RV). Along the axial direction, the computational domain is discretized into n number of control volumes. The set of governing differential Equations 1-4 have been discretized by using “finite volume method” (FVM), unsteady terms by using first-order implicit method for the first time step and second-order implicit method for all future time steps. Axial terms are discretized using first-order upwind method for the boundary nodes and second order upwind method for internal nodes. A more detailed discussion about these methods may be found from references (Xu and Morie 2014; Xu and Morie 2012; Wang 1997; Cai et al. 1994; Zhu and Matsubara 2004a, 2004b; Arablu and Jafarian 2013; Boroujerdi et al. 2011). Final output of the set of coupled non-linear differential equations becomes a set of algebraic equations which are then solved by using iterative methods. After cyclic steady state has been achieved, the performance parameters (such as cooling power, compressor work, COP) will be computed.