Boiler Feed Plumbing

On the shortest day of December 2015, Sentinel 7109 received another milestone of reassembly.

Twin Check Valve unit with single check valve to the right

The pipework connecting the two engine-mounted water pumps to the boiler's twin check valve was completed. The single check valve used with the cab mounted pump is in the shade to the right. (A check valve allows the water to only flow in one direction. Hence, water can be put into the boiler without it coming straight out again!).

The twin valve takes water from each pump but allows it to be recirculated to the water tank if not needed by operating the red handles. This is important because the engine pumps are always working when the loco is moving.

I'm really pleased with this pipework as it is original but was not fitted when the loco arrived at Midsomer Norton in 2004.

Steam Brake Air Tested

In June 2012, I last wrote about Sentinel 7109's steam brake cylinder. Time passes and I've learnt that restoration is not a rapid activity!

The brake cylinder was reinstalled on Monday 7th December 2015 and here it is in place bolted to the left hand frame member to the rear of the boiler. (Bearing in mind that I can only just lift the cylinder on my own, getting it into place under here was not a straight forward exercise and required a selection of trolleys, levers, bits of railway sleeper and a lot of ingenuity to get it home!).

Brake Off

Spot the difference!

Brake On

To see it in action, here's another of my little video clips (Also on YouTube).

Sounds like heavy breathing!

The testing involved connecting a compressed air supply to the Driver's Brake Valve (DBV) inlet. Movement in the video was controlled using the DBV itself as would be normal practice with a steam supply.

DBV Top Left

The brakes still need to be adjusted but that can't happen until the front drive chains are in place and the axles located for the correct chain tension.

Checking back over the 'blog, I've not been able to find anything on the Driver's Brake Valve itself. I've had the photos since December 2012 but they slipped through the net.

The Driver's Brake Valve has an operating shaft and three connections to it - the steam supply inlet from the boiler; the outlet to the brake cylinder and a drain to atmosphere to release the pressure on the cylinder piston to let the brake off after application.

DBV connections

DBV Operating shaft

The operating shaft is extended across the rear of the cab to allow the brake to be operated from either side.

Dual Controls 1927 Style!

I took the following photo just after taking co-ownership of 7109 in 2010. A few bits & pieces had been removed and examined ('played with'). There was a long journey ahead!

DBV in October 2010

For completeness, here's the Sentinel factory drawing of the DBV. It is a general drawing showing that it could be operated from either end although 7109 did not use it that way.

Sentinel DBV Sectional Drawing

Other locos mounted the DBV in the centre rear of the boiler with handles either side.

DBV in Sentinel 9599 (William Mk1)

Remote Control - 1927 Style in 2015

I began this small series three years ago here. With due regard to health and safety, I did not complete the construction as there would have been a trip wire to negotiate at the same time as squeezing into the right front corner of the cab where most of the vacuum braking and safety valve apparatus was being made resident. (I've lost count of the number of times I've had to breathe in very deeply to avoid impaling myself on the safety valves and vacuum gear).

The trip wire is now in place ready for the unwary (probably me on bad day!). There is a lot more to go in this corner and much not obvious in this photo.

Trip wire in place

Below the cab floor, the cable attaches to the exhaust condensate valve. (Also shown here is the new stainless steel braided (High-tech!) mechanical lubricator feed pipe to the regulator steam supply).

Underneath end of the remote control cable

The cable passes through the cab floor by the vacuum pipe.

Through the cab floor (1)

The two water feed pipes from the engine-mounted boiler feed pumps are showing - and still need to be linked to the boiler. The cable looks as if it will rub against the water pipe. Some care will be needed here.

Through the cab floor (2)

From a different angle:

Through the cab floor (3)

Looking at the photos in the earlier article, it brings home just how much has been done over those three years (and that the amount still to do is looking a lot more encouraging!)...

Shiny!

On Monday 30th November, Eric Miles and George Colbourne took a break from restoring the Fry's Sentinel Loco at the Avon Valley Railway and kindly visited Midsomer Norton bringing with them two brand new Sentinel Maker's plates for 7109.

Bare Metal Sentinel Loco Maker's Plate - Nice!

They have had a slight clean up so far and are ready to have the number punched on the blank rectangle at the bottom right. The background will be painted red as was the Sentinel tradition in 1927. I have yet to discover the exact shade of red required.