5. Condenser Tube Cleaning System5. Condenser Tube Cleaning System

Nuclear Plant & Heat Exchanger Engineering Section

P&ID P&ID around Condenser Tube Cleaning Systemaround Condenser Tube Cleaning System

Tube Cleaning System DescriptionTube Cleaning System Description

Condenser

injector

strainer

circulating pump

ball distributor

ball collector

ball sorterFRP Piping

The online tube cleaning system prevent fouling and deposit (scale, sludge, bio fouling and so on) inside the condenser tubes by circulating sponge rubber balls with the cooling water.

A ball distributor ensures even distribution of balls to the injectors.

Then the balls are pushed through the tubes by the C.W.

Then, the balls are collected by a strainer fitted on the condenser outlet CW pipe.

A ball circulating pump propels the balls into the circulation piping which in turn will re-inject them in the inlet C.W pipe.

A ball collector located between the pump and the injectors in enable to stop and collect the ball when necessary (for strainer grids backwashing for example).A ball sorter allows the automatic selection of worn out balls whose diameter is under inside tube diameter, and which are then not efficient any more.These balls are slightly larger than the tube ID and

are injected upstream the condenser through one or several injector for proper distribution.

Ball Strainer Ball Strainer Pressure tapings

Electrical actuators

The ball strainer consists of:-a strainer shell flanged and internally lined,

-two pressure tap

-one flange ball outlet pipe,

Electrical actuators

-one manhole for inspection

Ball Recirculation UnitBall Recirculation Unit

Ball pump

Ball sorter

Ball outlet valve (actuated valve)

Ball collector

Collector outlet valve (hand valve)

Ball Collector Ball Collector The collector mainly consists of a vertical cylinder tank.

The inside volume of the collector is divided by an internal perforated sheet in two volume.

One volume (upstream) in which flow the water and balls,

The ball collector is fitted with one hand valve, and one ball collecting actuated valve.

-Ball collecting actuated vale closed: Water circulation without ball

-Ball collecting actuated valve open: Water circulation with balls

second one (downstream side) through which only water flows (without balls).

The position on the ball collecting actuated valve is automatically controlled as follows.

Ball Injectors Ball Injectors

cooling water flow

ball flow

The ball injectors are fitted with support flanges on each cooling water inlet pipe.

The ball injectors are installed in such a way that the balls enter counter flow in the cooling water system, in order to obtain their even distribution.

Ball Distributor Ball Distributor

The ball distributor splits the flow of recirculation circuit (water and operating balls) towards the injectors. An internal flap enables the adjustment to get an even distribution of balls between the outlets.

Electrical Control Panel Electrical Control Panel The panel control:Grid position of the ball

strainerStart-up and shut-down

sequence of the ball pumpCirculation or collection ballsLow voltage current

instrumentationOperation of the systems

Differential Pressure Monitoring System Differential Pressure Monitoring System

DP level 1 (automatic backwash cycle) :

DP reading value with clean grid + 15 mbar

DP level 2 (emergency backwash) :

DP reading value with clean grid + 30 mbar

Ball Specification Ball Specification

Material : Sponge rubberBall diameter : 22 mm

( Tube inner diameter is 20.83 mm )Number of balls per system : 1000 pcs

Operation 1/2Operation 1/2 Automatic mode

･ operating to reach the highest performances of the condenser

Stand-by / off mode ･ to change worn balls by new ones or for

maintenance purpose

Trip mode ･ for long outage of the plant unit

How to operate the system in automatic mode

･ A timer “circulation time per day” allows to enter for each CTCS the number of hours balls will circulate through the condenser tubes each day.

＊ continuous mode(24hours per day)is recommended

･ In the backwash function, collection time is 20 min. and backwash time is 30 min.

Operation 2/2Operation 2/2

Preventive Maintenance 1/2Preventive Maintenance 1/2Cleaning balls

Every 2 weeks size of circulating balls has to be checked up.

Ball strainer1) visual check of the D/P : once a week2) check the grid actuator internal heater : yearly3) internal lining, grids, shafts : at outage

Preventive Maintenance 2/2Preventive Maintenance 2/2 Control panel

1) check the internal heater resistance and led : yearly

Ball pump1) lubrication : every 2,500 running hours2) alignment with motor : as defect noticed3) leak of mechanical seal : as defect noticed

Ball collector (as defect noticed)1) check the internal lining 2) clean sight glass

Ball distributor (as defect noticed)1) clean the sight glass2) to even distribution of balls / adjust the internal flap

Ball monitor 1) check the sorted- ball diameter/ eventually adjust

the ball sorter calibration gate

Corrective Maintenance 1/2Corrective Maintenance 1/2

Grid actuators1) no maintenance normally required.2) part replacement.

D/P transmitter1) no maintenance normally required.

Corrective Maintenance 2/2Corrective Maintenance 2/2

Ball pump1) collective maintenance.2) part replacement.

Manual ball valve1) no maintenance normally required.2) part replacement.

Valve actuator1) no maintenance normally required.2) limit switches adjustment.3) part replacement

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