The Windle sandwash plant (53.468777, -2.737466) was used for processing sand destined for the Pilkington glassmaking factories in St Helens. Its function was to produce material of consistent quality, which meant getting rid of oversized or undersized particles, blending different batches, and washing off surface-bound iron impurities which would otherwise make the glass too green. The sand itself came from various nearby sandpits on the Lancashire plain. The plant closed sometime during the 60s.
Some photos were taken in summer, some a few weeks ago. The place is boggy but not difficult to access and there are plenty of photos on the web, including a previous report on here https://www.28dayslater.co.uk/threads/pilkingtonas-sandwash-plant-st-helens-a-june-2010.51437/.
I was interested in this old factory mainly because most of the original machinery is still there; its a simple enough process so it ought to be possible to figure out how it all worked. However while I could see roughly what was going on, some aspects were baffling because bits were missing. So I headed down the road to St Helens library and had a look in their extensive archive of Pilkington-related material. Luckily I came across a hand-written 1961 HND thesis all about Pilkington’s sandwashers and sandpits (its actually mostly about another similar sandwasher in Rainford, now demolished). The diagram below is a combination of several illustrations in the thesis, and shows the main stages.
Briefly, water was added to the raw sand and the slurry fed into the mouth of a drum filter. The sand then passed though a conical device down into main washer and was eventually pumped into large draining tanks.
Views of the main hall, stairs and top gantry.
A view of the five filter drums that feed the sandwash lines running in parallel - some of these drums even still spin.
The crude slurry was introduced via a five-way splitter (right) onto the first metal mesh cone filter (middle) and sand emerged through the second nylon mesh filter (left).
The rejected gravel from the filters at both ends was funnelled down onto a conveyor belt which exited from the front of the building. This coarse material was trucked away and used for aggregate.
Sand from the drum filters fell into the ‘dewatering cones’ through another chute, sinking to the bottom. Excess water and fine particles overflowed into a channel round the top and was piped away via the hoppers. Conical valves with counterweights regulated the flow into the washing machine.
In the first compartment of the washing machine helical blades propelled the slurry against a countercurrent of water (introduced at the far end of the line) to a sump. Cups rotating in synch with blades then scooped up slurry from the sump and dumped it down a chute into the second compartment and so on down the line. Jets of water apparently helped rinse the cups (the feed lines are still there). The first two compartments have weirs on one side where the dirty water with a suspension of fines and clay drained off.
Overhead view of the five washer lines and a view down one.
Blades, overflow weir and a cup.
The slurry was washed down a chute into large cylinders (tundishes) with centrifugal pumps at the bottom.
The purified sand was then pumped down a common pipe into four large rectangular bins holding 1000’s of tonnes, where it was left to drain (it was used damp in the glassmaking process). These bins are now heavily overgrown forming their own little sandy microenvironments.
The platform on the left, reached by a ramp at the rear, may have been where the sand was scooped out.
A lot of water and power was needed and the basement of the main plant contains plenty of pipes and pumps.
The water was taken mainly from Rainford brook, which runs close to the plant.
I’m still hazy about a few aspects of this place such as how the sand slurry got to the top of the building (probably pumped), how water was recycled, and what the little extension on the roof at rear was used for.
The plant must have been an impressive sight in full swing, but even in 1957 the days of this beast were numbered - other papers in the archive show that there was an experimental cyclone-based washer also on the site, which having fewer moving parts, was proving more reliable. As far as I know local sand is no longer used and Pilkington gets its high grade silica elsewhere.
Some photos were taken in summer, some a few weeks ago. The place is boggy but not difficult to access and there are plenty of photos on the web, including a previous report on here https://www.28dayslater.co.uk/threads/pilkingtonas-sandwash-plant-st-helens-a-june-2010.51437/.
I was interested in this old factory mainly because most of the original machinery is still there; its a simple enough process so it ought to be possible to figure out how it all worked. However while I could see roughly what was going on, some aspects were baffling because bits were missing. So I headed down the road to St Helens library and had a look in their extensive archive of Pilkington-related material. Luckily I came across a hand-written 1961 HND thesis all about Pilkington’s sandwashers and sandpits (its actually mostly about another similar sandwasher in Rainford, now demolished). The diagram below is a combination of several illustrations in the thesis, and shows the main stages.
Briefly, water was added to the raw sand and the slurry fed into the mouth of a drum filter. The sand then passed though a conical device down into main washer and was eventually pumped into large draining tanks.
Views of the main hall, stairs and top gantry.
A view of the five filter drums that feed the sandwash lines running in parallel - some of these drums even still spin.
The crude slurry was introduced via a five-way splitter (right) onto the first metal mesh cone filter (middle) and sand emerged through the second nylon mesh filter (left).
The rejected gravel from the filters at both ends was funnelled down onto a conveyor belt which exited from the front of the building. This coarse material was trucked away and used for aggregate.
Sand from the drum filters fell into the ‘dewatering cones’ through another chute, sinking to the bottom. Excess water and fine particles overflowed into a channel round the top and was piped away via the hoppers. Conical valves with counterweights regulated the flow into the washing machine.
In the first compartment of the washing machine helical blades propelled the slurry against a countercurrent of water (introduced at the far end of the line) to a sump. Cups rotating in synch with blades then scooped up slurry from the sump and dumped it down a chute into the second compartment and so on down the line. Jets of water apparently helped rinse the cups (the feed lines are still there). The first two compartments have weirs on one side where the dirty water with a suspension of fines and clay drained off.
Overhead view of the five washer lines and a view down one.
Blades, overflow weir and a cup.
The slurry was washed down a chute into large cylinders (tundishes) with centrifugal pumps at the bottom.
The purified sand was then pumped down a common pipe into four large rectangular bins holding 1000’s of tonnes, where it was left to drain (it was used damp in the glassmaking process). These bins are now heavily overgrown forming their own little sandy microenvironments.
The platform on the left, reached by a ramp at the rear, may have been where the sand was scooped out.
A lot of water and power was needed and the basement of the main plant contains plenty of pipes and pumps.
The water was taken mainly from Rainford brook, which runs close to the plant.
I’m still hazy about a few aspects of this place such as how the sand slurry got to the top of the building (probably pumped), how water was recycled, and what the little extension on the roof at rear was used for.
The plant must have been an impressive sight in full swing, but even in 1957 the days of this beast were numbered - other papers in the archive show that there was an experimental cyclone-based washer also on the site, which having fewer moving parts, was proving more reliable. As far as I know local sand is no longer used and Pilkington gets its high grade silica elsewhere.
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