FIG.16 CHECKING THE BLOWING PRESSURE

The blowing pressure is controlled by raising or lowering the pressure control disc, thus increasing or decreasing the gap between the valve seat and the disc; the gap is set at approximately 2.5 mm (0.1in) on assembly. Adjustment is made by disconnecting the air relief valve and removing the lock pin coupling, and then rotating the pressure control disc. The pressure control disc must be locked in position after adjustment by replacing the lock pin coupling. The lock pin should engage one of the deep grooves in the pressure control disc; each groove represents approximately 0.2 mm (0.08 in) vertical movement of the pressure control disc.

The sootblower should be operated through several complete cycles, with steam on, to check that it is functioning correctly before finally putting it into service.

JULY 1996 FORM 13251

SECTION 5

OPERATING INSTRUCTIONS

General

The IK1M Sootblower can be operated from a remote panel or from push-buttons mounted on the sootblower terminal box or an individual starter box. Once started, the sootblower automatically completes its operating cycle and returns to the rest position ready for a further cycle.

Provision is made, also, for manual operation (Section 6.) 5.1 Operating Precautions

When the sootblowers are installed on a small boiler, the steaming capacity should be maintained at over 50% and the draft fans should be operating at a high rate of flow during the sootblowing period. This ensures that the amount of cleaning medium blown in is small compared to the amount of gases passing through the boiler, and also that the deposits removed by the sootblowers are carried through the boiler. If the firing rate is low, the sootblowing may agitate combustibles in the furnace and cause puffing.

On larger boilers, these precautions are not normally necessary, as the amount of cleaning medium blown in is usually small compared to the amount of gases passing through.

5.2 Blowing Schedule

When a steam generator is first placed into service, the tube surfaces have an immunity to ash and slag adherence. Consequently, it will appear, at first, that the recommended blowing pressures are higher than required. During this period, lasting for a few weeks, it may not be necessary to operate the sootblower very often. Later, after the tube surfaces have acquired a coating of residual slag, the deposits of slag and ash will be more difficult to clean and the recommended pressures will be more than likely required.

Before commencing blowing, reference should be made to the operating precautions given in paragraph 5.1. Normal recommended practice is to clean the boiler in the direction of the gas flow. The units nearest to the furnace operate first, followed by the superheater and economiser units. If heavy accumulations are to be removed, a few of the units in the rear passes of the boiler should be operated interchangeably with those in the first pass. This eliminates a heavy accumulation in the boiler output area. If a 'straight-through' schedule is employed, it is possible that accumulation removed from the superheater region will pile up in the economiser area. These recommendations are general ones, operating experience with the individual boiler is the most accurate guide.

SECTION 6

JULY 1996 FORM 13252

SECTION 6

MAINTENANCE INSTRUCTIONS

General

Maintenance instructions in this Section are grouped under the following headings for convenience: Operational Checks; Periodic Inspection; Annual Maintenance; and Major Overhaul. A maintenance schedule for each group is provided in Section 8, and Job Sheets, detailing the action to be taken, are provided in Section 12.

Lubricants, which should be kept readily available for maintenance purposes, are listed in Section 7.

6.1 Operational Checks

Checks should be made when the sootblower is operating to detect malfunctioning or blowing medium leakage. With the exception of blowing medium leakage, these checks are normally made by the operator.

6.2 Periodic Inspection

The sootblower should be inspected periodically to ensure that :-(a) All mechanisms are functioning correctly.

(b) All moving parts are adequately lubricated.

(c) Blowing medium is not leaking.

(d) Feed tube surface is in good condition.

(e) Lance tube/Element/Rake Arrg't surfaces are in good condition.

(f) Blowing pressure is correct.

The frequency of inspection will depend on operating conditions, but should be at least once per month.

6.3 Annual Maintenance

The IK1M Sootblower should be inspected annually for deterioration of all critical parts; these should be renewed, where necessary. Packing and lubricants should be renewed and mechanisms checked and adjusted, where necessary.

NOTE: Components on the carriage assembly which are sealed for life, should only be re-lubricated if dismantling has taken place. This does not apply to bearings and similar parts, which should be discarded and renewed.

Critical parts include the

following:-(a) Poppet Valve, including Air Relief Valve.

(b) Feed Tube.

(c) Lance Tube, Element or Rake Arrg't.

(d) Front Support Rollers.

(e) Limit Switches.

(f) Drive Nut.

(g) Guide Nuts

FORM 13252 JULY 1996 6.4 Major Overhaul

The IK1M Sootblower should be dismantled every three years for inspection and renewal of all wearing parts. Seals, packing and lubricants should be renewed at this overhaul. Wall sleeves and supporting steelwork should also be checked, and renewed if unserviceable.

NOTE Components on the carriage assembly which are sealed for life should only be re-lubricated if dismantling has taken place. This does not apply to bearings and similar parts, which should be discarded and renewed.

6.5 Manual Operation (Fig.17)

During maintenance, or in an emergency, the Sootblower carriage can be operated manually by using the retraction handle. After first removing the protective cap on the end of the gear reducer, the drive pin can next be removed and the square tang can now be turned with the handle. With the drive motor thus disconnected, turning the square tang clockwise results in the carriage travelling forward and the lance tube going into the boiler. Conversely, turning the square tang counter-clockwise results in the carriage returning towards the fully-retracted position.