AXIAL PUMP Senator. Libya

8/9/2019 AXIAL PUMP Senator. Libya

http://slidepdf.com/reader/full/axial-pump-senator-libya 1/40





Axial and Mixed flow:

Axial and Mixed Flow Pumps are the normal choice for

high-volume, low-pressure pumping duties and

particularly for large-scale primary water supplies, flood

control, irrigation and drainage. Such types are available in

a wide range of sizes and capacities.

It is a general characteristic of such pumps that the power

input curve is much flatter than that of a centrifugalpump, thus input power demand does not vary very much

with the working point. Hydraulic performance, however,

differs appreciably.

Rotodynamic Pumps




Axial flow pumps generate head pressure through an axial

motion developed by a combination of propeller and

internal vane design. The combination induces fluids to

travel strictly along the axial of the pump drive shaft.

The mixed flow pump employs a chamber /impeller /vane

design to impart both an axial and radial motion to fluids

traveling downstream.

Rotodynamic Pumps

This powerful motion is created by lifting the fluids with an

impeller, while simultaneously forcing fluids out against the

bowl like impeller chamber.




The outward movement known as an upper diffuser

section. By combining axial and centrifugal motion, the

mixed flow pump generates greater head pressure to

downstream fluids than is possible with a single motion

axial pump.

These differences are noted in the generated comparative

H-Q curve.

Rotodynamic Pumps




Rotodynamic Pumps

Q

η,HP,

Hd

Q

η,HP,

Hd

Q

η,HP,

Hd

Q

η,HP,

Hd

Q

η,HP,

Hd

Q

η,HP,

Hd




Rotodynamic Pumps

In the case of a mixed flow pump,

the H-Q curve tends to be steep,

with the point of maximum efficiency

displaced towards maximum

capacity.




Rotodynamic Pumps

The H-Q curve of an axial flow pump

has substantial falling characteristics

although the actual head obtainable

is much lower.

Efficiency is higher over a greater

(percentage) range of head than for

a centrifugal pump.




Rotodynamic Pumps

General form:

Driver Head

shaft

Seal

Pump

shaft

Impeller

Discharge

elbow

Column assembly

Bowls

Suction

bell

Axial and mixed flow pumps are

commonly mounted vertically,directly over a sump. This is most

often the case when the source of

water is a river or reservoir.

Fluids enter through a flared suctionbell that has been reinforced by

heavy vanes.




Rotodynamic Pumps

General form:

Driver Head

shaft

Seal

Pump

shaft

Impeller

Discharge

elbow

Column assembly

Bowls

Suction

bell

The vanes, in addition to lending

support to the suction bell, act todirect the liquid flow parallel to the

drive shaft as it travels upstream.

Once past the suction bell, fluids

encounter either an axial propeller or a mixed flow impeller.




Rotodynamic Pumps

General form:

Driver Head

shaft

Seal

Pump

shaft

Impeller

Discharge

elbow

Column assembly

Bowls

Suction

bell

While differing in design, both are

always dynamically balanced, one-piece castings, mounted on a

stainless steel pump shaft.




Rotodynamic Pumps

Driver:

Driver Head

shaft

Seal

Pump

shaft

Impeller

Discharge

elbow

Column assembly

Bowls

Suction

bell

The drive shaft may be encased in a

tube or open, with supports properlyspaced for intermediate shaft

bearings. Positive drive is provided

by a heavy-duty drive key and thrust

collar.

A variety of drivers may be used,

however, electric motors and right

angle gears are most common.




Rotodynamic Pumps

Driver:

Driver Head

shaft

Seal

Pump

shaft

Impeller

Discharge

elbow

Column assembly

Bowls

Suction

bell

These types of drivers can be

grouped into two categories:1. Hollow shaft drivers - the pump

shaft extends through a tube in the

center of the rotor and is connected

to the driver by a clutch assembly atthe top of the driver.




Rotodynamic Pumps

Driver:

Driver Head

shaft

Seal

Pump

shaft

Impeller

Discharge

elbow

Column assembly

Bowls

Suction

bell

These types of drivers can be

grouped into two categories:2. Solid shaft drivers - the rotor

shaft is solid and projects below the

driver-mounting base. This type

driver requires an adjustablecoupling between the pump and

driver.




Rotodynamic Pumps

Column assembly:

Driver Head

shaft

Seal

Pump

shaft

Impeller

Discharge

elbow

Column assembly

Bowls

Suction

bell

The column assembly is of two basic

types, either of which may be usedon close coupled units:




Rotodynamic Pumps

Column assembly:



1. Open line shaft construction

utilizes the liquid being pumped to

lubricate the line shaft bearings.




Rotodynamic Pumps

Column assembly:



2. Enclosed line shaft construction

has an enclosing pipe around the

line shaft and utilizes oil, grease or injected liquid to lubricate the line

shaft bearings.




Rotodynamic Pumps

Column assembly:

The column assembly will consist of

column pipe, which connects thebowl assembly to the discharge

head and carries the pumped liquid

to the discharge head, the shaft,

which connects the bowl assembly

to the discharge head, the headshaft, which connects the line shaft

to the driver.




Rotodynamic Pumps

Column assembly:

Column pipe may be either threaded

or flanged and may contain bearingsif required for the particular unit.

Note: Some units will not require a

column assembly, having the bowl

assembly connected directly to the

discharge head.

Note:




Rotodynamic Pumps

Discharge head assembly:






Rotodynamic Pumps

The discharge head supports the

driver and bowl assembly as well assupplying a discharge connection

(the underground discharge

connection will be located on one of

the column pipe sections below the

motor stand).





Rotodynamic Pumps

A shaft sealing arrangement is

located in the discharge head to sealthe shaft where it leaves the liquid

chamber. The shaft seal will usually

be either a packing box or

mechanical seal assembly.





Rotodynamic Pumps

Bowl assemblies:

The bowl assembly consists of

impellers rigidly mounted on thebowl shaft, which rotate and impart

energy to the fluid.

The bowls (or diffusers) contain the

fluid at increased pressure and directit vertically to the next stage and

eventually to the column pipe.




Rotodynamic Pumps

Bowl assemblies:

The suction bell or case directs the

fluid into the first stage impeller.Bearings are located in the suction

bell, discharge case, and between

each impeller.

Impeller




Rotodynamic Pumps

Bowl assemblies:

The rotating element is mounted in

an individual housing, which isusually replaceable and situated just

above the section bell, close to the

pump inlet.

The housing may be bronze,stainless steel or any other material

similar to the impeller.Why?

Impeller




Rotodynamic Pumps

Bowl assemblies:

The same resistance to shock.

The same thermal extension. Why?To keep a clearance between

impeller and casing as

designed (performance of the

pump).

Impeller




Rotodynamic Pumps

Bowl assemblies:

After emerging from the housing,

fluids travel past an upper diffuser chamber and out through the guide

case.

The guide case, consisting of a

column pipe and discharge elbow is

of welded steel plate or cast iron.




Rotodynamic Pumps

Bowl assemblies:

Sections are flanged or bolted

together.A registered fit is used to maintain

proper alignment on all mated parts.




Rotodynamic Pumps

Pullout options, which make for

easier maintenance and inspection,are a common feature of these

pumps, the best designs permit

removal of the entire bowl assembly

(including all rotating parts, diffuser,

impeller housing and suction bell)through the outer shell, without

disturbing either the discharge or

floor plate connections.

Pullout options:



Channel impeller pumps:

Rotodynamic Pumps

A channel impeller pump employs an impeller with

turbine-type blades mounted on the periphery running in

an annular channel (or channels) surrounding the

periphery of the wheel.

In practice, only two main subtypes emerge, known

generally as the peripheral pump and side channel pump

respectively.



Rotodynamic Pumps

The main difference is in the form and positioning of the

channels:


The peripheral pump has a double-sided channel in whichthe liquid circulates, this channel being located partly in

the cylindrical part of the casing and partly in the side

plates.

The side-channel pump has two channels cut in the sideplates only, adjacent to each side of the impeller blades.



Rotodynamic Pumps

Characteristics are quite different, eg the side-channel

pump is self-priming and can develop a much higher

head, although its efficiency is lower. Hence, the two are

distinct types.


The peripheral pump is also known as a regenerative

pump.



Rotodynamic Pumps

H-QEfficiency

BHP

H E A D , B H P & E f f i c i e n c y

100%

Peripheral

Capacity




Rotodynamic Pumps

H-Q

Efficiency

BHP H E A D , B H P & E f f i c i e n c y

100%

Side-channel

Capacity




Rotodynamic Pumps

H-Q

Efficiency

BHP H E A D , B H P & E f f i c i e n c y

100%

Side-channel

Capacity

H-Q

Efficiency

BHP

H E A D , B H P & E f f i c i e n c y

100%

Peripheral

Capacity




Rotodynamic Pumps

Centrifugal

Regenerative

Axial flow

Axial flow

Capacity

H E A D

Regenerative pumps have a

substantially straight and

sleep H-Q curve.

Pressure developed tends to

rise sharply with decreasing

capacity making this type

unsuitable for discharge

regulation by throttling. Power output falls with increasing

capacity.




Rotodynamic Pumps

Mixed flow

Axial flow

Centrifugal

Rotodynamic

Turbine

PUMP

Positive displacement

Diaphragm

Piston

Plunger

ReciprocatingRotary

Gear

Lobe

Sliding Vane

Screw



Turbine pumps (Regenerative):

Rotodynamic Pumps

Turbine pumps obtain their

name from the many vanes

machined into the periphery of

the rotating impeller. Headsover 900 feet are readily

developed in a two-stage

pump.




Rotodynamic Pumps

The impeller, which has very

tight axial clearance and uses

pump channel rings, displays

minimal recirculation losses.The channel rings provide a

circular channel around the

blades of the impeller from the

inlet to the outlet.




Rotodynamic Pumps

Liquid entering the channel

from the inlet is picked up

immediately by the vanes on

both sides of the impeller andpumped through the channel

by the shearing action. The

process is repeated over and

over with each pass impartingmore energy until the liquid is

discharged .

Date post:	30-May-2018
Category:	Documents
Upload:	senatorlibya
View:	220 times
Download:	0 times

AXIAL PUMP Senator. Libya

Documents