The screw driver is a common tool used to turn the screw to make it in place. It usually has a thin wedge head, which can be inserted into the slot or notch of the screw head. electric screwdrivers,best screwdrivers,felo screwdrivers Shangqiu Zhengtu Hardware Technology Co,.Ltd , https://www.ztlighter.com
There are mainly one character (minus sign) and cross (plus sign). There are also common hexagon screw drivers, including two kinds of hexagon and hexagon. Each screw driver has different specifications and can be customized.
According to different head types, screwdrivers can be divided into one character, cross, meter character, star (computer), square head, hexagon head, Y-shaped head and so on. One character and cross are the most commonly used in our life, such as installation and maintenance. It can be said that as long as there are screws, screwdrivers will be used.
Hexagonal head is not used much, commonly used in the hexagonal wrench, such as some machines a lot of screws are with hexagonal hole, convenient for multi angle force. We don't see many big ones. Small ones are often used to repair mobile phones, hard disks, notebooks and so on. We call small screwdrivers clock batch. We often use star T6, T8, cross pH0, ph00 and so on.
Centrifugal pump works
(1) The impeller is driven by the pump shaft to rotate, and the fluid located between the blades performs work. The fluid is subjected to centrifugal force and thrown to the periphery by the center of the impeller. 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. (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.