- •Comprehensive reading
- •Comprehensive reading What is a Centrifugal Pump?
- •What is a gear pump?
- •How do gear pumps work?
- •What is a Piston Pump?
- •How do Piston Pumps work?
- •What is a screw pump?
- •How do screw pumps work?
- •What is a vane pump?
- •How do vane pumps work?
- •Unit one. Auxiliaries words and expressions
- •Air compressor
- •Starting
- •Stopping
- •Maintenance and operating troubles and remedy
- •Heat exchangers words and expressions
- •Heat exchangers. Plate type. Operation, maintenance and troubleshooting. Words and expressions.
- •Symptom cause remedy
- •Distillation systems oil/water separator. Sewage treatment.Incirator. Words and expressions
- •Text distillation systems
- •Oil water separators
- •Sewage treatment
- •Incinerator
- •Words and expressions
- •Sea Water Desalination
- •Vocabulary
- •Vocabulary Section
- •Only for advanced Section I -- Pump Operation and Maintenance
- •Predictive and Preventative
Lesson 1. Pumps
suction piping |
всасывающий трубопровод |
discharge piping |
нагнетательный трубопровод |
suction head |
высота всасывания |
discharge head |
высота нагнетания |
displacement pump |
насос объемного типа |
axial flow pump |
осевой насос |
centrifugal pump |
центробежный насос |
reciprocating pump |
поршневой насос |
rotary pump |
роторный насос |
air vessel |
воздушный демпфер |
relief valve |
предохранительный клапан |
adjusting screw |
регулировочный винт |
bonnet assy |
колпак |
rotary vane displacement pump |
роторный лопастный объемный насос |
gear displacement pump |
шестеренный (зубчатый) объемный насос |
screw displacement pump |
винтовой объемный насос |
casing |
корпус |
gland |
уплотнение |
driving shaft |
ведущий вал |
guide vane |
направляющая лопатка |
thrust bearing |
упорный подшипник |
bearing housing |
корпус подшипника |
diffuser piece |
диффузорная часть |
impeller |
крылатка |
volute |
улитка |
single-entry centrifugal pump |
односекционный центробежный насос |
liquid path |
отверстие для выхода жидкости |
discharge nozzle |
нагнетательный патрубок |
impeller rotation |
зд. направление вращения крылатки |
motor half coupling |
приводная полумуфта |
spacer |
шайба, распорка, прокладка |
bearing bush |
втулка подшипника |
motor support bracket |
приводная полумуфта |
soft packed gland |
мягкая набивка |
shaft coupling |
соединительная муфта валопровода |
globe valve |
тарельчатый клапан |
non-return valve |
невозвратный клапан |
check valve |
пробный клапан |
gate valve |
клинкетный клапан |
wedge face |
поверхность клина |
wedge gate |
посадочное место клина |
A pump is a machine, used to raise liquids from a low point to a high point. A pumping system on a ship consists of suction piping, a pump and discharge piping. Even pump has a power end, which may be a steam turbine or an electric motor and a liquid end where the liquid enters or leaves the pump. The typical characteristics for the pump are the suction head and the discharge head. The suction head is the pressure of the liquid entering the pump or the difference in the level of liquid with respect to the level of the pump on the suction side. The discharge head is the pressure of the liquid leaving the pump or the level of liquid with respect to the level of the pump on the discharge side.
There are three main classes of pumps in marine use: displacement, axial flow and centrifugal. Displacement pumps can be either reciprocating or rotary. The operating principle of the reciprocating displacement pump is the following. As the piston moves upwards suction takes place below the piston and liquid is drawn in, while the discharge valve is closed. Above the piston liquid is discharged and the suction valve is closed. As the piston travels down the operations of suction and discharge occur on opposite sides.
A relief valve is always fitted between the pump suction and discharge chambers to protect the pump against excessive pressure.
The rotary displacement pumps operate by means of rotary parts which trap the liquid at the suction side and force it through the discharge outlet. According to the type of rotary elements there are rotary vane displacement pumps, gear displacement pumps and screw displacement pumps.
An axial flow pump uses a screw propeller to axially accelerate the liquid. The outlet passages and guide vanes are arranged to convert the velocity increase of the liquid into a pressure.
In a centrifugal pump liquid enters the centre of the impeller and flows radially out between the vanes. A diffuser or volute is then used to convert most of the kinetic energy in the liquid into pressure. There are single entry or double entry centrifugal pumps.
Various valves are fitted to the pumps. These include the following: globe valves, non-return or check valves; relief valves.
Exercise 1. Answer the following questions.
What is a pump?
What does a pumping system on a ship consist?
What are the typical characteristics for the pump?
What is the suction head?
What is the discharge head?
How many main classes of pumps are used in marine use? What are they?
What is the operating principle of the reciprocating displacement pump?
How do the rotary displacement pumps operate?
What kinds of pumps are defined according to the type of rotary elements?
What for does an axial flow pump use a screw propeller?
What for are the outlet passages and guide vanes arranged?
What are two types of the centrifugal pumps?
Exercise 2. Give Russian equivalents for the following.
Difference
with respect to
by means of
to occur
according to
to have a power end
the operating principle
to flow radially
Exercise 3. Translate into English.
Насос объемного типа может быть двух видов: поршневой или роторный.
В зависимости от типа роторных элементов различают три вида насосов: роторный лопастный объемный насос, шестеренный объемный насос и винтовой объемный насос.
В центробежных насосах жидкость движется по центру крылатки и вытекает между лопатками.
Насосы оснащены различными клапанами, включая тарельчатый клапан, невозвратный клапан, пробный клапан и предохранительный клапан.
Comprehensive reading
Exercise 1. Read and translate the text.
Operation and maintenance instructions
Starting (the centrifugal pump and axial flow pump)
Open the suction check valve wide, opening at the same time the air vent on the top side.
Close the air vent as soon as liquid flows out of it.
Start the motor leaving the discharge valve closed.
Check that direction of rotation is as indicated by the arrow.
Slowly open the discharge check valve until operating requirements are reached.
Check on the ammeter that power requirements do not exceed the motor possible rating.
Check tightness of the packing gland. Leaks must be reduced to a few drops which is required to prevent harmful heating of the packings and the shaft.
During operation
The pump output is to be controlled by operating on the discharge valve and never on the suction valve which must always remain wide open.
Stopping
After switching off the motor close the suction and the discharge valves of the pump.
Exercise 2. Study words and expressions.
arrow |
стрелка |
direction |
направление |
requirement |
требование |
ammeter |
амперметр |
to exceed |
превышать |
rating |
расчетная величина |
tightness |
герметичность, зд: затяжка |
packing gland |
сальник, уплотнение вала |
output |
производительность |
to prevent |
предотвращать |
Pump Type |
Basic Description |
Key Features |
Applications Used |
Recommended Media (Fluid) |
Advantages |
Flow Rate Ranges |
Total Head Ranges |
Horse Power Ranges |
Centrifugal Pumps |
General name for pumps with one or more impellers. Many types and configurations for different applications. |
One or more impellers. Casing is volute or diffuser type. Electric motor driven, or other drive. |
All sorts of liquids can be pumps with them. Liquid should not contain air or vapors and have low viscosity. |
Water and relatively thin liquids (won't pump thicker oils). Can pump liquids with or without solids if proper impeller type is chosen. |
Best pump choice for lower viscosity (thin) liquids. Highest flow rates of all pump types. |
5 -200,000 gpm |
10 - 7,500 ft |
0.125 – 5,000 hp |
Axial Flow Pump |
Axial Flow pumps are a very high flow, low head type of pump. Also called a propeller pump. |
Single stage, high specific speed impeller for high flow low head. |
Flood dewatering, power plant circulating water pump, evaporator services, and irrigation. |
Water and relatively thin liquids. Can pump liquids with or without solids if proper impeller type is chosen. |
This pump type is the best type to achieve very high flow rate with very low head. |
5,000 200,000 gpm |
10 30 ft |
10 - 1,500 hp |
Piston Pump |
Piston pumps are a type of reciprocating positive displacement pump that has, double acting reciprocating pistons. |
Pump includes one or more double acting pistons, an inlet and outlet check valve for each piston. |
In applications where high pressure is needed. |
Water and other thin liquids, including liquids containing abrasives. |
Slower speeds may mean less maintenance. |
5 - 700 gpm |
50 - 5,000 psi |
1 - 500 hp |
Pump Type |
Basic Description |
Key Features |
Applications Used |
Recommended Media (Fluid) |
Advantages |
Flow Rate |
Total Head |
Horse Power |
Screw Pump |
Screw pumps use two inter-meshing screws, driven by timing gears, move oils and other viscous liquids. |
meshing screws don't drive each other. |
Fuel transfer, elevators, and if needed relatively high flow rates of viscous liquids. |
Oils, fuels, and other high viscosity liquids. Also handles two-phase liquid/gas mixtures. |
Highest flow rate of positive displacement pumps. |
50 - 15,000 gpm |
50 4,500 psi |
5 - 5,000 hp |
Gear Pump |
Liquid is pumped by passing between two meshing gears and the surrounding casing. There are internal and external gear types. |
Internal and external gear types. Doesn't handle solids or abrasive liquids. |
Most common pump for clean oils and other viscous liquids. |
Oils and other high viscosity liquids. Usually only suited for clean liquids (no solids). |
Most widely used for clean oil services. Few moving parts, simple construction. |
1 - 1,500 gpm |
10 - 2,500 psi |
0.5 – 2,000 hp |
Vane Pump |
Vane pumps use a rotor with vanes located in slots, rotating inside a shaped casing. As the rotor turns, the vanes move in and out of the slots. |
Sliding vanes are often made of carbon. |
An alternative to a gear pump for transferring oils and other viscous liquids. Also good for thinner liquids. |
Oils and other high viscosity liquids. Usually only suited for clean liquids (no solids). Also good for thin liquids like gasoline and water. |
Good for both thick and thin liquids, so often chosen for terminals and truck unloading where many types of liquids are handled. |
5 - 2,500 gpm |
20 - 200 psi |
1 -300 hp |