What’s in a hole?

The capabilities of the new Weir Valves & Controls factory in Elland were tested recently following an order from Oil Turbo Compressor (OTC) in Iran for 30 large control valves, in sizes 18”,20” & 24”.

Fig 1. Two of the 24” valves during final assembly.

The new Elland factory has been set up based on the ‘lean’ philosophy with an efficient workflow layout and a structured approach to workflow planning. In every discipline, from sales, drawing office, production control, purchasing and assembly, the size and nature of the valves required detailed capacity planning, in order to satisfy our customers expectations.

Fig 2. An indication of the number of holes drilled in one of the cages.

Machining the 30 large bodies and machining the 30 cage trims which required 10,000 holes would need additional capacity to what was currently available. There were only a few companies in the UK who had the correct size of machine tools to manufacture such valve components and even fewer with the required experience. One of these companies was Valvetek Machining, a company set up using machine tools from the old Weir Valves & Controls factory in Huddersfield.

So straight from order placement the contract had to be carefully managed and castings were produced in a phased manner and quickly sent for machining to avoid potential bottle necks in the process.

The valve cages produced a different set of challenges, the first being to get hold of suitably sized material, but then the main challenge was to control the flow of work. There was no one company that could do all the operations to produce a cage, so the production had to be carefully controlled so that the component parts all came together for the final assembly. The cages had to be rough machined, drilled, shrunk together, welded and then ground to complete the cage assembly.

Fig 3. The valves shortly before hydro testing, the valve on the left is plated up ready to go on test.

Further challenges came towards the end of the assembly operation, when the valves came to be painted, they were too big to be painted internally, so each valve had to be shipped out for painting. Due to the size of the valves, they had to be dried in air rather than in an oven which also doubled the time normally taken.

The customer’s confidence in our manufacturing and valve design was confirmed shortly after they visited the Elland factory, to perform a final inspection on some of the valves, when they placed an order for an additional set of valves.

Adrian Croft
Product Manager - Blakeborough
Valves & Controls

acroft@weirvalve.com
+44 (0) 1422 282000