A special point was the production of an Egger axial flow pump in size DN 800 in titanium grade 12 (RPP 805 LB 7.2)
The Egger elbow pump was produced for a client in Russia, for the evaporation of a slurry brine. The axial pump, which weighs over 2 t, hangs in the pipeline and is driven by a 160 kW motor via V-belt drive.
1, role: chemical pump is used to transport liquid and increase its pressure machine
2. Special requirements for pumps in chemical production:
(1) can meet the needs of chemical process
(2) high temperature and low temperature
(3) corrosion resistance
(4) wear resistance
(5) no leakage or little leakage
(6) it can transport the liquid in the critical state
(7) reliable operation
3. Classification of pumps:
(1) according to working principle and structure: positive displacement pump
(this kind of pump is divided into reciprocating pump and rotary pump), vane pump (this kind of pump can be divided into different impeller structure for centrifugal pump, mixed flow pump, axial flow pump and vortex pump), other types of pump
(2) according to the process use, it is divided into: process pump, utility pump, auxiliary pump, pipeline transport pump, etc
4, chemical centrifugal pump working principle: before the start of the chemical centrifugal pump, pump and suction pipe should be filled with liquid, this process is called pump.
After starting the motor, the motor drives the impeller to rotate through the pump shaft, and the vane in the impeller drives the liquid to rotate together. Under the action of centrifugal force, the liquid in the impeller is thrown to the outlet of the impeller along the blade passage, and is sent through the volute to the discharge tube.When the liquid in the impeller is thrown to the outlet of the impeller, the inlet center of the impeller has formed a low pressure, in the suction tank and the center of the impeller of the liquid between the pressure difference, the liquid in the suction tank under the action of the pressure difference, it is continuously through the suction pipeline and suction room into the impeller.In this way, the impeller in the process of rotation, one side of the continuous inhalation of liquid, one side of the continuous inhalation of liquid to a certain amount of energy, the liquid out.The centrifugal pump is thus continuously connected to work.
Centrifugal pump in the process of operation, often occur "gas binding" phenomenon, that is, the pump into the air, so that the pump can not work normally bottom valve is a check valve, before the valve closed
5. Classification of centrifugal pump:
(1) according to the impeller suction classification: single suction, double suction
(2) classification by series: single-stage centrifugal pump, multi-stage centrifugal pump
(3) classification by head: low pressure centrifugal pump, medium pressure centrifugal pump, high pressure centrifugal pump
6, rotor refers to the rotating part of the centrifugal pump, it includes impeller, pump shaft, shaft sleeve, bearing and other parts
7, the impeller is the centrifugal pump to do work parts, relying on its high-speed rotation of the liquid to do work and achieve liquid transport
8. According to the structure, the impeller can be divided into: closed impeller, open impeller and semi-open impeller
9. When the bending direction of the blade is opposite to the rotating direction of the impeller, it is called back curved blade; otherwise, it is called forward curved blade (back curved blade has higher efficiency).
10, the main role of the pump shaft of the centrifugal pump is to transfer power, support impeller to maintain normal operation in the working position
11, the commonly used shaft seal device has packing seal and mechanical seal
12, the packing seal is through the packing gland pressure packing, so that the packing deformation, and the shaft of the outer circular surface contact, to prevent the outflow of liquid and air inhalation pump.
The tightness of the packing seal can be controlled by adjusting the tightness of the packing gland.A reasonable degree of tightness should allow the fluid to drip out of the stuffing box, 15 to 20 drops per minute.When the conveying temperature of low-pressure centrifugal pump is less than 40℃, graphite packing or cotton packing with butter penetration are commonly used.Graphite impregnated asbestos packing is used for conveying liquids with temperature less than 250℃ and pressure less than 1·8MPa.For the transportation of petroleum products with temperature less than 400℃ and allowable working pressure of 2.5MPa, use metal foil to cover asbestos core packing
13. Mechanical seal structure and working principle:
Depending on the stationary ring and the moving ring of the end of the joint, and as a relative rotation of the sealing device, known as mechanical seal, also known as the end seal.
14. The main performance parameters of the centrifugal pump are flow, lift, speed, power, efficiency, vacuum absorption and cavitation allowance, etc
15, the output of the pump in unit time of liquid, known as flow
16, unit weight of liquid, through the pump after the energy, known as the centrifugal pump head or head
17, centrifugal pump impeller per minute of revolution is called the speed, that is, the speed of the centrifugal pump is the number of revolutions per minute of the pump shaft
18,Power refers to the work done per unit time the work done by the pump to the output liquid per unit time is called effective power
The ratio of the effective power to the shaft power delivered to the pump spindle by the prime mover per unit of time is called the pump power
19. Due to the possibility of overload in pump startup or operation, the power of the motor selected by the manufacturer is 1.1~1.2 times of the power of the shaft
20. The relationship between the performance parameters of the centrifugal pump can be expressed by curves on the coordinate diagram.The performance curve that represents the relationship between the main performance parameters of the centrifugal pump is called the performance curve of the centrifugal pump. The performance curve of the centrifugal pump is divided into flow head curve, flow power curve and flow efficiency curve
21. Q-h curve, namely, flow head curve, represents the relationship between flow and head of the centrifugal pump.When the flow is zero, the head is a fixed value, with the increase of the flow, the head usually shows a downward trend
22. Q-n curve is flow power curve. With the increase of flow Q, axis power N rises gently.When the flow rate is zero, the shaft power is minimum and the outlet valve of the centrifugal pump is closed. At this point, the flow rate Q is zero and the starting power is minimum, which can prevent the motor from burning out due to overload
23. Q-- curve, that is, flow power curve.From the point of view of energy saving, people always want the pump to work at the highest efficiency point, but it is not realistic in the actual production. Normally, the pump should work at no less than 90% of the highest efficiency area
24. Adjustment of centrifugal pump:
(1), Change the flow regulation of the pipeline characteristic curve
① , throttle control of outlet pipeline
② , bypass regulation
(2), Change the flow regulation of the performance curve of the centrifugal pump
① , change the working speed of the pump
② , outside diameter of cutting impeller
25. Energy saving of centrifugal pump:
(1) choose the appropriate pump model to make the centrifugal pump work in the high-efficiency area
(2) reduce the pipe resistance and the required head of the pipe
(3) improve the impeller structure to improve the impeller's ability to do work
(4) reduce the impeller diameter or reduce the impeller speed
26,Reciprocating pump is a positive displacement pump.Characteristics of reciprocating pump: uneven flow, discharge pressure can be infinitely high, flow and discharge pressure independent, with self-priming capacity
27,Diaphragm pump is a special form of positive displacement pump.It relies on the back and forth encouragement of a diaphragm plate to change the volume of the chamber to inhale and expel fluid
28,Gear pump has self - priming capacity, flow and discharge pressure has nothing to do
29,Screw pump is the use of one or several screw sniffs together to transfer liquid volumetric rotor pump.
Characteristics: the medium is transported along the axial movement, the liquid flow is continuous and uniform, the pulse is small, the flow rate changes with the pressure is small, the operation is more stable than gear pump, five vibration and noise, high efficiency, with self-priming ability, long life and so on.However, the processing technology is complex and the manufacturing cost is high, so it is suitable for conveying oils (such as lubricating oil, fuel oil, etc.) with lubricating ability and without solid impurities and high-viscosity liquids (such as banana liquid, chemical fiber viscose, etc.).
30,A machine that pumps gas out of the equipment so that the pressure in the equipment is less than one atmosphere is called a vacuum pump
Vacuum pump classification: according to its working principle is divided into mechanical vacuum pump, jet vacuum pump and physical and chemical vacuum pump
31, magnetic drive pump and belong to the same without shaft sealing structure of the shield pump, only on the structure of the precise seal and no moving seal, used for conveying liquid can ensure a drop without leakage
32, communicate magnetic application in centrifugal pump with magnetic transmission principle, all is the use of magnet can attract the ferromagnetic material in between the body and the magnetic field has the characteristics of the magnetic effect, rather than a ferromagnetic material does not affect or rarely affect the size of the magnetic force, so can not contact through the magnetic conductors for power transmission, the transmission device called a magnetic coupling.