Keep the Good, Replace the Weak Link

Boiler feed regulating valves at a UK power station

Much critical plant is mechanically sound but let down by one unreliable component. Replacing the whole asset means pipework or civil work, long outages and high cost. Re-engineering only the weak link keeps the serviceable, fit-for-purpose equipment that would be costly and disruptive to replace.

At a large UK power station, IPT Engineering and Beck did exactly that on the boiler feed regulating valves. The upgrade was designed jointly by Beck and IPT, manufactured by Beck, and installed and commissioned with IPT’s support.

The Problem

Sound valves, unreliable actuation

The feed regulating valves control water into the boilers. The 1980s high-pressure valves were sound, but their original linear hydraulic actuators were not.

Valve positioning was not repeatable, making feedwater regulation harder than it should be
The actuators needed regular maintenance, with recurring costs at every outage
The standby (start-up) valves had been out of service for several years for the same reasons, which made boiler start-up difficult for the operators
No usable OEM design data or drawings were available, and possible undocumented trim changes affected the stem dimensions
Any added load on the high-pressure pipework needed structural approval, and work had to fit planned outages and permit windows

How We Did It

Re-engineer the actuation, leave the valve alone

The station had already converted its ID and FD fan dampers from linear hydraulic drives to Beck rotary electric actuators. Their success gave the confidence to tackle the more demanding feed regulating valves.

Survey what is there. With no drawings, IPT measured the valves in place: stems and threads, bonnet bolt patterns, gland and trim positions, lever geometry and stroke.
Size on evidence. The seating force was worked out from published engineering data for comparable boiler feed valves and confirmed by further checks, avoiding both under-sizing and an oversized, slow drive.
Engineer the interface. Beck and IPT designed a fulcrum mounting kit that bolts to the existing bonnet. It turns the rotary actuator’s output into the valve’s original linear stroke, so the valve is unmodified and operates exactly as before.
Seat it properly. A Beck Tightseater coupling applies a controlled seating force on every closure, with visible compression to confirm the plug is seated.
Check the knock-on effects. IPT supplied weights, centres of gravity and outline drawings so the pipework assessment could be signed off before fitting.
Prove one, then roll out. The first unit was commissioned on site with IPT. Small fit issues found on that install were designed out, so later kits fitted straight out of the crate.

Original hydraulic feed regulating valve actuator — BeforeOriginal feed regulating valve drive

Beck electric actuator on a boiler feed regulating valve with a fulcrum mounting kit — AfterBeck actuator on the original valve, through a fulcrum mounting kit

The Results

Accurate control, standby plant back in service

The first unit controlled accurately with no issues from commissioning, and the station ordered the next set straight away
The main valves were converted across the station’s units using one proven kit design
The standby valves were returned to service after years out of use, making boiler run-up easy for the control room
Hydraulic power units, pipework and oil removed from the valve area
No known failures or maintenance issues on any of the converted valves to date

See the wider power station actuator replacement case study, and our actuator services.

What This Means for Water & Wastewater

The same approach for long-life water assets

Water and wastewater sites have the same mix of robust, long-life valves and gates driven by ageing or unreliable actuators. Replacing the weak link instead of the whole asset:

costs a fraction of full replacement, with no civils, pipework or structural changes
fits within planned shutdowns, keeping the asset in service around the work
removes hydraulic oil, and its leak and environmental risk, from the site
restores accurate, repeatable control and brings standby plant back into service for resilience
extends the life of assets that still have decades of mechanical service left

Beck actuators modulate continuously with no duty-cycle limits and need no routine maintenance, which suits filter, aeration, sludge and penstock duties. See Beck for Water & Wastewater.