Boiler feed pumps (BFPs) are one of the most critical auxiliary machines supporting a thermal power plant or steam intensive process. Any unplanned downtime of a BFP can interrupt boiler function, completely stop power generation, and cause unexpected plant or process outages. In some cases, a BFP failure can even lead to a low-water casualty of a boiler resulting in possible boiler-tube damage. Thus, a high degree of reliability and functionality is crucial for pumps in this service. BFPs must be designed specifically to operate reliably under severe conditions such as rapid load changes and frequent starts & stops while maintaining the high discharge pressures associated with the application without unacceptable wear and tear.
Beyond these typical design and operational challenges inherent to BFPs, Coffin’s core industries-served have exhibited unique challenges that have shaped Coffin’s superior BFP design over the past century.
High reliability and low maintenance are critical requirements, as power plants cannot abide plant outages. A BFP failure can result in a total plant shutdown, or a ship being stranded at sea or in a collision if the failure occurs while the vessel is maneuvering. CTPI is world-renown for providing robust, highly reliable feed pumps, and boasts shipboard pumps that continue service after 30+ years!
A small package footprint and ease of installation is required in limited-space machinery spaces and engine rooms – BFPs must be compact without compromising performance. CTPI offers the smallest BFP through unparalleled high-speed operation and the use of a single pump & turbine shaft in steam-turbine driven configurations.
Operation with a wide range of capacities is required of all marine BFP’s since shipboard-boiler loads vary significantly depending on whether a vessel is in port or at anchor, maneuvering, slow steaming, or operating at full sea speed. CTPI BFPs accomplish this with the capability to operate at varying speeds. Our steam-turbine-driven BFPs have inherent variable-speed capability and can be supplied with a patented constant-discharge-pressure or constant-differential-pressure governor. The same features can be incorporated into CTPI’s electric-motor-driven BFPs using variable-frequency drive technology. In addition, the use of multi-vaned diffusers significantly reduces the radial-reaction forces that can act on centrifugal-pump impellers during operation at off-design capacities. Also, all impellers are balanced with both front and back wearing rings to minimize axial thrust. A robust rolling-element thrust bearing absorbs any residual axial thrust, which can change during variable-flow operation.
Quick startup of a standby BFP can sometimes be necessary. CTPI’s BFPs do not require a warm-up period or pre-lubrication of bearings prior to startup and can be brought up to full speed very quickly.
Unattended operation of BFPs is often a necessity due to reduced crew size. As a result and to meet ship-specification requirements, CTPI’s BFPs can be furnished with various alarms and trips. In addition, a complete condition-monitoring system is available.
Any leakage of feedwater from a BFP must be replaced, usually with makeup produced by a vessel’s onboard distilling plant. In addition, this water will often end up in a vessel’s bilges after which treatment using an OWS is required. To virtually eliminate this pump leakage, all CTPI BFPs are fitted with mechanical seals.
Reduced overhaul periods and downtime mean that BFP routine maintenance must be completed quickly. Because CTPI BFPs are designed to facilitate in situ maintenance, all normal wear parts can typically be replaced in 8 to 12 hours without the need to remove pump or turbine housings.
Onshore applications typically serve commodities and power-generation markets where cost-competitiveness of capital equipment is often the most important factor considered during procurement. Through superior design of high-speed, compact pumps, Coffin strives to offer the most cost-competitive BFP possible over its lifetime.
Coffin parts and service are available on a 24-hour basis, anywhere in the world. All parts provided are inventoried at our parts and service centers or factory locations in:
- New Jersey, USA (HQ)
- Louisiana, USA
- Rotterdam, Netherlands
- Singapore, Malaysia
- Abu Dhabi, UAE
- Tokyo, Japan
- Busan, Korea
- Rio de Janeiro, Brazil
Pumps are often subject to dynamic motion and high G-forces in heavy seas – CTPI’s BFP components, including housings, shaft, bearings, bolting and mounting baseplates are designed to be able to resist dynamic loads and still perform reliably.
Long term inclined operation may be required given certain vessel trim/list conditions – BFPs must be able to maintain adequate lube oil system performance despite inclined operation and significant sloshing.
Shock survivability for Naval combatants is a critical BFP requirement to ensure the reliability of the steam system after severe shock loads. CTPI is proud of its pump models that have successfully passed high-impact shock tests and the hundreds of installations aboard US Navy vessels, as well as our participation in the ongoing LHD Wasp-Class BFP replacement project!