electrostatic precipitator rapper control basics

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Electrostatic Precipitator Rapper Control Basics

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MRC-NT Rapper Control

Precipitator operating and optimizing products

Components

Features

Functions

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MRC-NT Rapper Control


How is a rapper constructed?

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Purpose of a Rapper Control System

Energize rappers, electric vibrators, and air solenoids.Permit adjustment of the frequency and duration of energization.Permit adjustment of the energization intensity.Identify faulty devices and type of fault

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Purpose of a Rapper Control System - Continued

Allow for storage of multiple programs for various operating conditions.

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Major System Components

Keypad and Display UnitPower BoardPower Supply CardOutput CardPower ModulePower and Control Transformer


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Keypad and Display UnitPower BoardPower Supply CardOutput CardPower ModulePower and Control

Transformer


DisplayBacklit Liquid Crystal (LCD)AlphanumericFour Lines of TextTwenty Characters per line

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Keypad Sixteen Key

Tactile FeelHermetically SealedDual Function

Parameter SelectionNumeric Selection

Individually Labeled

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The Keypad and Display Unit is used for field programming the control.

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The Power Board contains a duplicate processor that contains the backup program and any field changes that have been made. The Keypad and Display Unit could actually be removed after programming is complete and the rapper control will continue to operate. This board also directs the firing pulse to the appropriate output card and point on that card.

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The Power Supply Card contains the low voltage power supplies that feed the card rack and the Keypad and Display Unit.

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The Output Card acts as a switch to send the rapper firing pulse to the appropriate output point/rapper.

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The Power Module converts the AC from the Power Transformer to full wave DC to power the rapper coil. It also sends the firing pulse to the card cage where it is directed to the proper output by the Power Card.

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The Power transformer supplies the AC voltage to the Power module, while the Control transformer provides the AC voltage to the Power Supply Card.


Cycle Clock•An MRC can have any number of cycle clocks.

•Each cycle clock controls a chosen group of rappers. The timing of the cycle clock is the time period between consecutive energization of the same rapper in a rapper group.

•A rapper group is any number of rappers controlled by a cycle clock.

•The cycle clock is programmable between one second and 100 hours in one-second increments.

•Upper and lower limits of cycle clock timing are be pre‑programmed into the MRC.


Wait Cycle Clock

•Each cycle clock has a counterpart wait cycle clock.

•The wait cycle time is the time period between energization of the last rapper in a rapper group and the re-energization of the first rapper in the same group. •The wait cycle clock for rappers is programmable from zero seconds (no wait) to 100 hours in one-second increments.


Rapper Intensity

There are three ways to adjust rapper/vibrator intensity:

1. Each device individually

2. Each group of devices individually

3. All devices simultaneously

For magnetic impact type rappers, the intensity is measured and adjusted in inches of hammer travel.


Repetitive Energization

The rappers in each group can be programmed to energize from 1 to 9 times before the next rapper in the same group is energized.

Select

Any rapper can be selected to display its operating parameters (intensity, wait and cycle clock number, and wait and cycle clock timing).


Step

Once a rapper has been selected, the control can be advanced sequentially to display all rapper parameters, one at a time.

Repeat

Repeatedly energizes any chosen rapper every 3 seconds, for troubleshooting purposes.


Sequence

Energizes all rappers in a chosen group at a faster than normal clock time. This rapidly cleans the electrodes associated with a chosen rapper group.

It is useful if excessive sparking caused by buildup is noted, or to clean various areas of the precipitator prior to internal inspections.

This parameter also allows all rappers in all groups to be energized in sequence at a fast rate, and allows all internal electrode surfaces to be cleaned rapidly during precipitator offline periods.


Master Intensity

•Allows the intensity of rappers in the same group or on the entire precipitator to be increased or decreased simultaneously.

•This is very useful for fine-tuning the rappers/vibrators during fuel switching.


Multiple Program Storage

•Six separate and distinct rapper programs are available to the user.

•They are mutually exclusive of one another and allow field programming of timing and intensity for such operating conditions as high loads, upset conditions, varying fuel sources, special maintenance routines, etc.

•Once programmed into memory, the separate programs can be called into use with a few simple keystrokes.

•The factory default program is always available for immediate recall.


Rapper Failure Alarms

•The operation of each rapper is constantly monitored as it is energized. Should a fault occur (short or open rapper coil or field wiring), the single rapper is removed from service; the operation of the other rappers/vibrators is unaffected.

•When a rapper is removed from service, the number of that rapper is displayed by pressing the alarm check key.

•If more than one rapper has been removed from service, repeatedly pressing the alarm check key will display these rappers in numerical order.

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Typical Rapper Roof Layout

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Typical Rapper Control

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Typical Rapper System

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Questions?

electrostatic precipitator rapper control basics

Documents

products keypad

various operating conditions

rapper firing pulse

appropriate output card

card rack

output card acts

permit adjustment

appropriate output pointrapper