Triangular Tubular Boiler Patent (1856/466)

It is generally recognised that Thomas Messenger started his horticultural business in 1858, when he developed his first known horticultural building. However, he laid the foundations of his successful enterprise, which was significantly more than just horticultural buildings, as early as 1853 when he started experimenting with a new design for a solid-fuel boiler.

The result was a radical and unique boiler design, which became known as a “Triangular Tubular Boiler”. It was essentially a highly modified saddle boiler with triangular instead of cylindrical tubes, which were placed horizontally, terminating at each end in free water spaces, thus making a larger surface area available for heating. The pipes were so arranged as to form the sides, top and bottom of the furnace, those above the fire being most numerous, and those beneath forming the furnace bars and the return pipes (see Thomas Messenger’s Triangular Tubular Boiler for details). Using this method Thomas Messenger claimed, “The heat cannot escape without doing threefold the work it would in any other manner of construction[1].

He decided to try to patent his invention and on 23rd February 1856 submitted the application – No. 1856/466, simply entitling it “Improvements in Boilers”. The patent, which was successfully sealed six months later on 15th August 1856, was both his first and probably his most successful single patented invention. The boiler proved to be a great success and sold in many thousands over the next twenty years. It was only in the late 1870s that it was effectively replaced, when Messenger & Co., introduced a new range of boilers, known as the “Loughborough” boiler.

Patent Specification

SPECIFICATION in pursuance of the conditions of the Letters Patent, filed by the said Thomas Goode Messenger in the Great Seal Patent Office on the 16th August 1856.

TO ALL WHOM THESE PRESENTS SHALL COME, I, Thomas Goode Messenger of Loughboro’, in the County of Leicester, Plumber, send greeting.

WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters Patent, bearing date the Twenty-third day of February, in the year of our Lord One Thousand eight hundred and fifty-six, in the nineteenth year of Her reign, did, for Herself, Her heirs and successors, give and grant unto me, the said Thomas Goode Messenger, Her special license that I, the said Thomas Goode Messenger, my executors, administrators, and assigns, should at any time agree with, and no others, from time to time and at all times thereafter during the term therein expressed, should and lawfully might make, use, exercise, and vend, within the United Kingdom of Great Britain and Ireland, the Channel Islands, and Isle of Man, an Invention for “Improvements in Boilers” upon the condition (amongst others) that I, the said Thomas Goode Messenger, my executors or administrators, by an instrument in writing under my, or their, or one of their hands and seals should particularly describe and ascertain the nature of the said Invention, and in what manner the same was to be performed, and cause the same to be filed in the Great Seal Patent Office within six calendar months next and immediately after the date of the said Letters Patent.

NOW KNOW YE, that I, the said Thomas Goode Messenger, do hereby declare the nature of the said Invention, and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement thereof, reference being had to the Drawings hereunto annexed (that is to say): –

My Invention consists of surrounding the fire with a number of triangularly or other shaped tubes, which form water spaces, extending from the front to back, and secured at each end by iron cement, or other suitable means, to sockets cast on inner plates, with sides and ends and flanges, to which are screwed front and back plates. By this arrangement a water space is formed between the inner and outer plates, which communicates with the tubes. Water admitted at the bottom or lower tube or tubes becomes heated, circulates freely through all the tubes and water spaces, and rises to an outlet at the upper part of the boiler. The furnace bars are cast with notches, and rest between the bottom row of tubes. The boiler, formed as just described, would only be applicable to heating purposes; and to convert into a steam boiler, I add a steam box or chest, which I cause to communicate with the water spaces, through which the water ascends and descends, and circulates though the power part of the steam chest. The steam fills the upper part of the chest, and may be taken off for any purpose required.

Figure 1 of the accompanying Drawings is a transverse section of this boiler, shewing the form of tubes and tubular fire bars; Figure 2, front elevation of the same; Figure 3, back elevation, shewing inlet and outlet pipes; Figure 4, longitudinal section of the boiler, shearing the connection of the tubes and the chambers; and Figure 5, a perspective view, with part of the brickwork removed. The same letters refer to similar parts in all the Figures.

A, A, is the brickwork of the furnace; B. B. are a series of triangularly shaped tubes, extending parallel or nearly so to one another from the front to the back part of the furnace. These tubes are secured at each end with iron cement in sockets a, a, cast on the inner plates C, C1. The plates C, Cl, are cast with sides, ends, and flanges. To these plates the front and back plates D, D1, also having sides, ends, and flanges, are bolted or otherwise fixed. By this arrangements a space marked A1, Figure 4, between the plates C and D, C1, and D1, is formed, and this space is in communication with the triangular shaped tubes of the boiler. Water is supplied from the inlet pipes B1, B1, and becomes partially heated before entering the tubes; after passing, through them, the water rises to the outlet pipe C11, to circulate through the pipes in a vinery or other house to be heated, and returns to the inlet pipes B1, B1. H flue or chimney through which the smoke passes; I is the furnace door; and K, ash-pit. To fit a new tube for a damaged one or to clean the boiler, it is only necessary to unbolt the places C, C1 or D, D1, or both, when the worn tube can be removed and a new one put into its place without in any way disturbing the remainder or injuring the brickwork of the furnace or boiler. The plates C, C1, and D, D1, being again secured, the furnace is complete as before. The boiler may be made capable of doing ally increasing the number and length of the tubes.

And having now described the nature of the said Invention, and the manner in which the same is to be performed, I declare that I claim,-

First the placing in a boiler of a number of triangularly or other shaped tubes, parallel or nearly so to each other, at such a distance and in such a position as to allow the heat of the fire to pass freely between or around them, in the manner herein-before described

Second, the constructing of the outer plates of the water-tight chambers in separate parts, in the manner and for the purposes herein-before described.

And, third, the general arrangement of the furnace and boiler, constructed and operating in the manner herein-before described, and represented in the Drawings hereunto annexed.

In witness whereof, I, the said Thomas Goode Messenger, have hereunto set my hand and seal, this Ninth day of August, in the year of our Lord One thousand eight hundred and fifty-six.


Patent Figures





  1. The Morning Post, 3rd April 1857.