CHAPTER 28 Pump Operation And Maintenace Flashcards
Where are rings on centrifugal pumps?
Where rings are found on dynamic centrifugal pumps at points for moving in the moving parts, are very close together like between the impeller, and the casing the smaller the clearance between the wear rings the smaller, the amount of water leaking from the discharge side of the pump to the suction pump in the higher, the pump efficiency Waring’s are easily and cheaply replaced are usually made of bronze and cast-iron, because they tend to wear, in a smooth manner.
Compression type packing
Made of soft pliable, yet durable material. Usually the packing material is lubricated by graphite or grease, called the Sacher end, not supposed to stop leakage entirely. It should only throttle the fluid, as lubrication comes from slight leakage of the fluid from the pump, or an emergency from a lubricant in the packing When the pressure in the stuffing box is below atmospheric pressure Aircon leak in when this is the case stuff in boxes provided with a ceiling, water connection and a lantern ring. The lantern ring is also called the ceiling cage, and it serves to distribute the ceiling water to the parking, which helps prevent air leakage and lubricate the parking.
Mechanical, seal, advantages, and disadvantages
Require less maintenance do not produce where of chefs or chefs leaves. Reduce leakage to a minimum can be designed to work under very high temperatures and pressures. Disadvantages are having a greater first cost than packing when they fail the pump must be taken out of service for a longer period to replace the seal all types of mechanical seals feature to flat ceiling faces with her at a right angle to the pump, one of the face is called a sealing ring, and is held in position by spring. The other ceiling face, which is in contact with the ceiling room is called the matting ring
Difference in rotating mechanical seal and stationary, mechanical seal
And both of them, the ceiling ring and spring, are held in place by the shell, but in the rotating seal, the ceiling ring spins with the shaft in the matting ring his stationary in the housing were with the stationary seal The ceiling ring is stationary in the housing in the matting ring rotates with the shaft.
Shaft, misalignment, and flexible couplings
Most electric motors drive centrifugal pumps directly. There are two types of misalignment that can occur the first being angular misalignment in the second being axial misalignment the motor and pump were connected by a rigid coupling. This could cause overheating excessive wear increase power consumption, vibration, and noise. Poor installation or assembly is one of the main reasons of unsatisfactory service. Flexible couplings are used because shaft misalignment can happen, even if the installation is perfect, they are not a cure all method. The original alignment still needs to be as close as possible straight edges can be used to check axial alignment, and a tapered feeler gauge is used for angular alignment for more accurate measurements, a dial indicator, which measures in thousands of an inch can be used
Two types of pump bearings
Number one shell or sleeve Baron
Number to bowl or roller bearing
Theoretically, the maximum lift of a pump at sea level is
10.34 m or 33.9 feet
The sum of static head and dynamic head is the what
Total head
