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Maintenance today.Tom completed some routine work on the Small Exhauster big end bearing. In the pix the bearing shells have been removed for inspection and adjustment. meanwhile, John took the opportunity to process 1500 liters of fuel and pump from the receiving area to the bulk storage tank.
After several successful operating open days we are beginning to understand the various eccentricities of the new boiler. Minor tweaking continues, and this week we installed a diagnostic ammeter to the control panel, and modified the electrical circuits to allow continued feed water dosing with the pump selected to manual.
With operations using some fuel , today we took the opportunity to transfer 2500 litres from temporary storage to the main tank, refilling the facility. We still have another 1800 litres in temporary storage. Open day today and after some tweaking, the boiler met all expectations. With six machines running, the high/low fire was modulating at 99 -94 PSI, and steam pressure was modulating 99 - 85 PSI.
For record, the following parameters are noted: Oil pressure at Burner input = 8 PSI. Oil pressure at High-fire nozzle = 14 Bar (reduced from 16 Bar) Oil temperature = 190 degrees F. On-board oil lock out thermostat set 90 deg. On-board oil heater thermostat set 100 deg. (these two readings indicate the thermostat indicator scale and do not indicate actual oil temp) Back-end temp = 800 deg +/- 10 degrees. Back-end explosion flap set at open 30mm at the flap lowest measurable position. Routine work day today and much achieved. Our volunteer sparkie ran a new 6.0mm sub-main direct from the Engine room switchboard to the boiler, providing increased electrical quality and security. Also general lighting fixtures containing PCB's were removed and/or replaced. Our volunteer electronics guru cleaned, adjusted and recorded the boiler no-flame photocell circuit. Our (fast becoming) expert pipework volunteer, re-ran boiler drain pipework, while others made various temporary fixes permanent, and nozzle research continued. A test run indicated that while we are on the right track, and operational, more boiler control tweaking will probably be required.
On the outside, a couple of survey students took positional readings on the chimney, and we look forward to hearing the results. Sunday 27/July/2014.
A good run today for the first full open day with all the machines running and supplied from the new boiler. During last weeks commissioning a few issues were identified and we began to address these today. The two new thermostats fitted to the on-board fuel heater were tweaked and a neon indicator added to the low temp lock-out thermostat relay. No further low oil temp lock-out occurred. Boiler back-end over temperature became an issue, even when we fitted a smaller 6.0 gal/hour nozzle. While on high-fire we had abundant steam generating capacity, but back-end temp restricted the use of this setting. We did manage to find a suitable compromise between machine speed and high-low fire modulation to achieve a stable operating condition, (a short high-fire cycle - a few minutes - when operating pressure could be achieved before a backend temp trip) Observations clearly demonstrated available steam output was restricted only by back-end temp and, given this sorted, the boiler was capable of producing well above our routine demand. We are working on a solution. |
GWM Operations Group BlogAuthorJohn is a Dunedin Gasworks museum operations group volunteer. Archives
January 2015
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