Among the more profitable was the introduction of a centrifugal pump. In a licensing agreement drawn up in 1923 with the Unchokeable Pump Company Limited, Blackstone’s gained the right to produce that company’s pumps for the next twenty years. On agreeing to a royalty payment of ten per cent of the net selling price Blackstone’s took over all the pump company’s patterns and drawings. But, by a further agreement six years later Blackstone’s acquired full ownership of the pump company’s patents.
The Unchokeable pumps are capable of moving hard or soft solids in fluids and semi-solid materials. The liquid or semi-solids mixture is forced through the pump casing between two revolving plates that form part of the impeller, not part of the casing side plate. Two diametrically opposed impeller ports allow the unrestricted flow of material and gave rise to the pump’s uncompromising name. They were usually driven by a direct-coupled electric motor, but models for belt or direct drive from diesel or petrol engines were available.
The ability of this pump to deal with a wide variety of materials soon found a ready market with municipal authorities who installed them to handle treated and untreated sewage. Many more were set to work in sand and gravel pits, while others were to be found pumping slurry in quarries or aboard sea-going dredgers. Building contractors used small Unchokeable pumps for dewatering trenches.
Just before the Second World War Blackstone’s began a withdrawal from the pump market, but production of the pumps did not to an end until early in the nineteen-sixties.
From soon after the First World War the Carter brothers began working to develop an improved for of fuel injection system for their engines. Their work culminated in 1924 with the introduction of the ‘Spring Injection’ mechanism. Simple in both design and operation it allowed a measured amount of fuel to be pumped to the injection chamber at a precise moment and for sufficient time for the fuel to be fully burnt. With close control of fuel consumed and an ability to start from cold and to run on practically any fuel, the company claimed the spring injection engine could successfully challenge steam in its last stronghold, the power station steam turbine.
The first engine with the new fuel system provided power and lighting for the Palace of Engineering at the British Empire Exhibition held at Wembley in 1924 and 1925. The new system also enabled Blackstone’s to produce their first high revving diesel engine, the BHV designed by Frank Carter. This predated by six years the Gardner Brothers famous LW engine, which was designed specifically for automotive use: and, as history shows, with more success.
The BHV developed 10 bhp per cylinder at 1000 rpm, each cylinder having a separate spring injector. Carter experimented with the BHV in several road vehicles, usually elderly lorries: a 1916 Thornycroft and an early Pierce-Arrow among them. Reliable performance figures are hard to find but there does seem to have been considerable economy over similar petrol engines.
Within A.G.E. both Aveling’s and Garrett’s attempted to enter the commercial vehicle engine market. At Leiston Garrett’s modified one of their QL chassis with a McLaren-Benz oil engine but this proved to be too under-powered and slow revving for a road vehicle. So in 1930 a specially designed chassis was built specifically for a 6 cylinder BHV engine. This vehicle was extensively tested over the following eighteen months, or so, before the Garrets works were closed.
Even if the testing had not been brought to a premature end it is doubtful if this vehicle would have ever been put into production with the BHV engine. Garrett’s also put the BHV engine into a small production run of agricultural tractors, both wheeled and tracked. Again, it was the closing down of the Leiston works that brought this application to an abrupt end.
This engine’s strength was its adaptability to static applications; driving power and lighting plants, pumping equipment, etc. However, at Rochester, Aveling and Porter used the BHV engine in a range of road rollers. This arrangement continued after the break up of A.G.E. with the setting up of Aveling and Barford. Spring injection engines had been used by A and P to power their rollers from early in the engine’s production life.
To meet the demands of the small power user Blackstone’s introduced the so-called ‘No Trouble’ petrol engine in 1922. This compact, reliable and simple vertical engine was ideal for use in workshops driving air compressors and small electrical generators etc. It was originally designed as a side valve engine developing 5 bhp but grew into a range of four sizes of overhead valve engines from 2¼ to 7bhp running on either petrol or kerosene. These stayed in production until 1935. The title ‘No Trouble’ only applied to the 5 bhp side valve engines and should not be given to the overhead valve engine.
At the other end of the power scale was the mighty TN8. This eight-cylinder vee engine was built in 1931 for the steel rolling mills of Pemberton Tinplate Co. Ltd of Llanelly, Wales. Its job was to drive a four-mill rolling plant with a 110 tons flywheel at 36 rpm continuously for five and a half days a week (126 hours), twelve months a year. In addition it had to provide all the electric power for driving hot and cold rolls, shears and bar cutters, the cranes and the lighting.
For this the Carters and Blackstone’s produced what was to be their largest engine. With 18 feet long, four-throw crankshaft that could withstand the overload shocks, cylinders of 18 in bore and 24 in stroke the engine developed 1,250 bhp at 250 rpm. Carters’ spring injection system enabled the engine to maintain output regardless of load and to work efficiently at a low speed.
As this pioneering engine successfully achieved what it had been designed for; a second, four-cylinder version was built for Swansea Steel Products in 1935. It is thought these engines were scrapped in the nineteen-fifties when the Welsh steel industry was going through a major shake-up after nationalisation. If anyone knows when I would be pleased to hear.
On 1st September 1933 an agreement was reached between M. C. Spencer, representing the receivers, and the three Blackstone brothers, Edward, Harold and George. This provided for them to acquire the Blackstone Company and to appointed joint managing directors pending further arrangements for the sale of Company shares and the re-organisation of the Company. George became Company Chairman. The following month an announcement in the local newspaper, the Stamford Mercury, stated that the Blackstone family and some of their “friends” has purchased the whole of the share capital.
The family’s “friends” were Barclays Bank Ltd. At a meeting at Aldwych House on 1st November 1933 ownership of the Company passed entirely into the hands of Barclays. George Blackstone resigned as Company Chairman to be replaced by James H. Gold of Barclays and John R. Caoul came onto the Board. An arrangement was made with Barclays Bank for an advance of £150,000 to the Company secured by the shares now held by Gold, Caoul, and by Edward, be Harold and George Blackstone; the latter having but one share each. This money was passed over to the Receiver for A.G.E. in payment and redemption of all outstanding debentures of the Company issued by A.G.E. A new Debenture was created and issued to the bank.
The reasons for George Blackstone’s resignation are unclear. He has often been portrayed as the scapegoat for the serious financial position in which the Company found itself. However it was he, along with his co-directors and those of Aveling’s and Barford’s who had questioned the activities of the A.G.E. Chairman, G. E. Rowland.
Harold V. Blackstone was appointed Works Director and placed in charge of both the Agricultural Department and of Buying. Edward E. Blackstone was appointed Joint Sales Director, alongside J. R. Caoul, with control of the commercial staff. Stanley E. Blackstone became Assistant Works manager to Frank Carter, succeeding to the position of Works Manager in 1934 following Carter’s death. Soon after Frank Carter’s death his brother Tod resigned.
Frank and Tod Carter’s last design was the EPV which was begun in July 1933.This was a totally enclosed vertical engine with an 8½ in bore and 11½ in stroke developing 40 bhp per cylinder at 600 rpm. It had opposed side valves and swirl combustion chambers, similar to the later horizontal spring injection engines. The enclosed design was neat and elegant; accessibility through the side covers was easy and quick. It was claimed that a piston could be drawn within ten minutes. The four-cylinder prototype was fitted with Blackstone’s patent ‘cCc’ (Carter’s Compound Cam) fuel injection equipment.
Automatic forced lubrication was employed, with an oil-cooler at the rear of the engine. Engine cooling was by an external centrifugal water pump. Inlet air passed through a bank of filters, also on the rear. The EPV went into production in 1934, the first to be sold, a six- cylinder engine, No. EPV6 189182 was dispatched on
16 June that year. The later improvement of Carter’s EPV led to the development of the EV by George Hallewell. The current E type with an output in excess of 1000 bhp per cylinder is the direct descendant of the EPV.
In November 1935 Lloyds Bank Ltd. took over the ownership of the Company from Barclays. J. H. Gold resigned as Chairman to be replaced by William Halford Lawson of Lloyds. All but three of the Company’s shares were transferred to Lloyd bank Nominees Ltd. The remaining three shares were transferred to Lawson, Caoul and Ernest Blackstone, the latter becoming the last and only shareholding member of the family. Harold and Edward Blackstone stayed on as directors.
One of the first acts of J. R. Caoul on joining the board was in 1934 when he negotiated a ten-year production agreement with Massey-Harris Co. Ltd., of Toronto, by which all the agricultural products of the Blackstone company were to be sold through a centralised organisation. It may felt that this was the spectre of the old A.G.E. system arising. But, instead of a number of disparate companies coming together only Blackstone and Massey-Harris were involved. Massey-Harris was possibly the largest manufacturer of agricultural machinery outside of Europe and Blackstone’s celebrated haymaking implements had been produced for nearly a century. Both were able to draw on each other’s expertise in manufacturer and selling.
Reminders that Blackstone & Co was still a major producer of agricultural implements, especially of hay harvesting machinery.
It was agreed that Blackstone’s entire agricultural output was to be manufactured to the specific requirements of, and sold through, the Massey-Harris organisation. They were to bear the title the ‘Massey-Harris-Blackstone’ series. From now until 1944 all agricultural machinery produced at Stamford carried the Massey-Harris name. There is no doubt that this arrangement allowed Blackstone’s to stay afloat during a very difficult period.
During January the following year (1935) members of the Board of R. A. Lister and Co. Ltd. could be seen roaming about in the Stamford works as arrangements were made for that company to take over. The Works Manager, S. E. Blackstone, was sent to Lister’s works at Dursley, Gloucestershire. In his absence Colin Mellerup, son of one of Lister’s Directors was appointed temporary Works Manager.
Soon after this, on 21 April 1936, W. H. Lawson and J. H. Caoul resigned. Caoul sold his interest to C. Percy Lister and he and Anders Eilers Mellerup were appointed Chairman and Director in their place. It was decided by the new Board to accept an offer of a £150,000 loan from Sir Bernard Greenwell in exchange for 4.800 unissued £10 shares in the Company. The Company Minutes do not give the reason for this operation, or indeed who Sir Bernard was. However, by July these shares had been transferred to R. A. Lister and Co. Ltd.