Centrifugal pump main working principle: (1) the impeller is driven by the pump shaft rotation, located between the blade fluid doing work, the fluid by the centrifugal force, thrown from the center of the impeller to the periphery. When the fluid reaches the periphery of the impeller, the flow rate is very high. (2) The pump housing collects liquid that is thrown from the vanes and flows in the direction of the gradual enlargement of the volute-shaped passage in the housing to convert the kinetic energy of the fluid into static pressure energy and reduce the energy loss. Therefore, the role of the pump casing is not only to pool the liquid, it is more an energy conversion device. (3) Principle of Liquid Absorption: The high-speed rotation of the impeller forces the liquid in the center of the impeller to be thrown away at a high speed, so that a low pressure is formed in the center of the impeller. Therefore, the liquid in the lower tank is continuously sucked up. Barrage phenomenon: If the centrifugal pump in the shell before the start is full of gas, then start the impeller center gas is thrown there can not be formed in a large enough vacuum, so tank liquid can not be sucked up. This phenomenon is called gas binding. In order to prevent the phenomenon of gas binding, centrifugal pump should be filled with foreign liquid to fill the space before pump starts. This step is called filling pump. In order to prevent the liquid poured into the pump casing due to gravity flow into the lower slot, the pump inlet pipe at the inlet with check valve (bottom valve); if the pump position below the tank surface, then start without irrigation Pump. (4) The outer circumference of the impeller to install the guide wheel, so that the pump liquid energy conversion efficiency. The guide wheel is a fixed, bladed ring located on the periphery of the impeller. The bending direction of the blade is opposite to the bending direction of the impeller blade, the bending angle of the blade matches the direction that the liquid flows out from the impeller, guiding the liquid to change direction smoothly in the passage of the pump casing so as to minimize the energy loss and convert the dynamic pressure energy into High static pressure energy. (5) balance hole on the rear cover to eliminate axial thrust. The pressure of the liquid leaving the periphery of the impeller is already high and some of the liquid will seep to the rear of the impeller rear cover and the liquid inlet at the front of the impeller is under pressure and thus produces an axial thrust pushing the impeller to the pump inlet side. This easily causes the impeller and the pump housing contact wear, severe vibration will occur. The balance hole leaks part of the high-pressure liquid to the low pressure area to reduce the pressure difference around the impeller. But this will also reduce the pump efficiency. (6) shaft seal device to ensure normal and efficient centrifugal pump. Centrifugal pump in the work of the pump shaft rotation and the shell does not move, during which if the ring gap is not to be sealed or seal is not good, the outside air will infiltrate the low pressure area of ​​the impeller center, so that the pump flow, efficiency decreased. Serious when the flow is zero - gas tied. In general, a mechanical seal or a packing seal can be used to achieve a seal between the shaft and the shell.
Serological Pipette
Disposable serological pipettes with polyester fiber plugs are ideal for tissue culture applications. Crisp, black, highly legible permanent graduations prevent ambiguity and guarantee precise reading and accurate dispensing within ± 2%. Reverse graduations show volume removed or remaining on all pipettes larger than 1mL. Generous negative graduations provide additional pipetting volume. Yongyue's serological pipettes are made from transparent USP Class VI polystyrene sterilized by gamma irradiation. Each lot is free from pyrogens, DNases, and RNases.Yongyue's plastic serological pipettes are produced under the strictest protocols and offer the highest degree of accuracy.
The pipettes are supplied with an aerosol barrier plug that prevents both liquid and aerosols from contaminating the pipettors.
The serological pipettes are produced from crystal clear polystyrene (PS) and are color coded for easy volume identification. Available in 1mL, 2mL, 5mL, 10mL, 25mL and 50mL sizes.
In addition each Pipette now features:
Crisp and bold easy-to-read graduation marks
Reverse graduations on all volumes
Negative graduations on all volumes
1, 2 and 5mL pipettes feature one-piece construction
10, 25 and 50mL pipettes feature three-piece construction
1 ml Serological Pipette,50 ml Serological Pipette,10 ml Serological Pipette,5 ml Serological Pipette,25 ml Serological Pipette,Serological Pipette 2ml
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