m O @ 80% B D E F | 9 2 Activity 3 Name Introduction to Fluid Power ** POWER-260
ID: 1766372 • Letter: M
Question
m O @ 80% B D E F | 9 2 Activity 3 Name Introduction to Fluid Power ** POWER-260. ASSOCIATED LEARNING ACTIVITIES Analysis of Hydraulic Pump Information Sheets This activity involves procedures designed to show how a fluid component manufacturer presents technical information about the pumps they design, manufacture and market. Appended to this activity is a typical technical information sheet for a series involving pumps with several displacements. Read the sheet carefully and then answer the following questions. Activity Questions 1. Describe the general characteristic of this pump series including pumping mechanism type, housing material, bearing type, etc.. 2. What is the continuous pressure rating of this pump series? 3. What is the operating speed rating of this pump series? In what type of installation would it be critical to know the range of acceptable operating speed? 4. Discuss the information provided relating to inlet line pressures. Why is there a difference in acceptable pressure drops between the indicated operating speeds? Why do you think the pressure is limited when the inlet line is charged? 1 e 9 E AddressExplanation / Answer
1. The given pump data refers to displacement pumps.
For this type of pump the flow is approximately constant with increasing pressure, but reduces slightly due to higher leakages at higher pressures.
The flow rate is approximately proportional to rotational speed and displacement (in3 or cc/rev)
Typically the pumping mechanism can be one of the following:
a) Bent axis axial piston pumps
b) Swash plate pumps with axial pistons
c) Radial piston pumps with eccentric cam ring
d) Radial piston pumps with eccentric shaft
e) Externat gear pumps
f) Internal gear pumps
g) Screw pumps
h) Vane pumps
i) Others
Typically the materials of construction are
-Casing-Alloy/stainless steel
-Shaft-Alloy/stainless steel
- Internals(gears,pistons etc.) Alloy/stainless steel
Bearing types typically are
-Taper roller bearings for bent axis axial piston pumps
-Axial roller thrust bearings for swash plate pumps with axial pistons
-Etc.
2. The continous pressure rating the maximum pressure the pump can generate. From the given data
Continuous pressure rating= 2500 psi( 172 bar)
3. The operating speed rating is (range) is 1200-3600 RPM.
In gear pumps, the oil enters the pumping chambers along the gear circumference. On entering the pump, the fluid quickly attains the rotational speed of gears and is hence subjected to centrifugal forces. These forces try to push the oil back to the inlet line and out of the pumping chamber. Therefore, the maximum pump speed should be limited and the inlet pressure should be high enough to avoid this back flow phenomenon.
4. The data related to acceptable inlet line pressure are not available here.
However, the following may be noted with regard to suction line pressure drop.
Cavitation occurs when the suction line absolute pressure falls below the saturation vapour pressure corresponding to operating pressure of the fluid. If there is excessive friction pressure drop in the suction line, the saturation vapour pressure may be reached and cavitation starts. Cavitation produces loss of capacity, high wear in internals and noise.
In addition to static friction pressure drop the suction line also experiences pulsating pressure drop due to pulsating nature of the pump flow. This pulsating pressure drop depends on operating speed of the pump. Hence the restriction on acceptable pressure drop in suction line is more restrictive at higher operating speeds.
The discharge pressure is kept limited (by use of relief valve etc) such that the pump casing and downstream equipment including pipes and tubes etc. are protected from overpressure.
(Please note that 4 subquestions need to be answered as per Chegg guidelines)
-
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.