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Monday (2019.1.14) https://bbs.hcbbs.com/thread-2260284-1-1.html 1. Like vane centrifugal pumps, positive displacement pumps can also experience cavitation. (True) 2. Under normal circumstances, centrifugal fans have a high air volume, while axial flow fans have a high pressure. (False) Tuesday (2019.1.15) https://bbs.hcbbs.com/thread-2261759-1-1.html 1. When performing dynamic balancing on components, the testing speed of the dynamic balancer should be the same as the actual operating speed of the component. (False) 2. Among the materials used for the end faces of mechanical seal friction pairs, both graphite and SiC possess certain self-lubricating properties. (True) Wednesday (2019.1.16) https://bbs.hcbbs.com/thread-2263133-1-1.html 1. The hydrostatic pressure in the pump body = 1.5x the design pressure, with the design pressure being less than the nominal pressure of the outlet flange. (True) 2. The total length of M16x80 double-ended studs according to GB898-1988 standard is equal to that according to GB901-1988 standard. (False) Thursday (2019.1.17) https://bbs.hcbbs.com/thread-2264588-1-1.html 1. Pumps are equipped with many auxiliary pipelines, and the minimum bending radius of each pipeline depends on its diameter; the larger the diameter, the greater the minimum bending radius. (True) 2. Electromagnetic and ultrasonic flowmeters are non-contact type flowmeters that avoid interfering with the flow of the medium. (True) Friday (2019.1.18) https://bbs.hcbbs.com/thread-2265502-1-1.html 1. Internal spring and bellows-type single-end face mechanical seals are suitable for applications involving media containing large particles. (False) 2. The metal surfaces in contact with O-rings in static seals need to undergo additional hardening treatments. (False) Saturday (2019.1.19) https://bbs.hcbbs.com/thread-2266997-1-1.html 1. The outer surface of stainless steel pump bodies is usually not painted. (True) 2. Grease can be stored for a long time, and there is no such thing as it becoming expired or ineffective. (False) Have a great weekend!