NEIMME: Lamps
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No. 1 DAVY LAMP. |
Made by H. Watson, Newcastle upon Tyne.
CONSTRUCTION.
Gauze. Single iron gauze 61/2 ins. high, 1 ? ins. diameter of 28 mesh, with double cap.
Burner. Round wick, 1/4 ins. diameter with pricker adjuster through small hole in oil vessel.
Lock Screw.
Other features. The oil vessel has the early type of spout feed.
HISTORICAL NOTE.
This lamp is a development of the lamps made by Sir Humphrey Davy towards the end of 1815 and first used in January 1816 at Wallsend and Hebburn Collieries.
After Davy had experimented on the passage of flame through small diameter tubes and gauzes, he made trials with candles and oil lamps which had gauzes between the flame and the gaseous atmosphere. The results were satisfactory and progress was then made to produce more robust lamps for mine use.
The gauzes used by Davy were 28 mesh and from that time most English lamps were made with 28 mesh gauzes until 1922, when 20 mesh 27, s.w.g. gauzes were permitted in certain cases. He found also that a tall narrow gauze was safer than a wide one. It will be found that Davy lamps do not have gauzes exceeding 7" high and 11/2 " diameter.
Davy fully realised that without any shield his single gauze lamp would allow the passage of flame to the external atmosphere if the velocity of the explosive atmosphere reached about 300 feet per minute. He recommended the use of an extra gauze cap at the top as an extra safeguard in case the top of the gauze became dangerously hot owing to the burning of gas within the lamp. Further he recommended that double gauzes should be used when conditions were very dangerous. Seldom were double gauze lamps used, however, and specimens are rare. Whereas the single gauze lamp has, almost invariably, three standards, the double gauze lamp generally had four.
Davy illustrated to that noted local mining engineer, Buddle, how external ignition could be obtained and told them how, by careful use of the lamp and suitable shielding, they could be prevented.
The Davy lamp was soon in common use in British and Continental mines. Owing, however, to the lack of instruction to the miners on its limitations it did not lead to an immediate reduction in the number of explosions.
Great progress was made in the design of safety lamps from 1816 onwards and it is remarkable that the Davy lamp was still commonly used in the early part of the twentieth century.
The candle power of a Davy lamp was very low, being of the order of ? to 1/4 c.p.
No. 2.
DAVY LAMP.
Presented by J. Straker-Nesbit.
This lamp is generally similar to No. 1. The only noteworthy differences are that the gauze is 7 ins. high and a screw lock is combined with the cap of the oil spout.
(See description of No. 1.)
On permanent loan to N.C.B., Graham House, Longbenton.
General Purposes Committee - 7th October 1965.
Council - 16th December 1965.
No. 3.
DAVY LAMP.
Presented by T.C. Renwick.
This lamp is generally similar to No. 1. The only noteworthy differences are the addition of a metal screen some three inches high round two thirds of the circumference to shield the flame in high velocity air currents and to reflect more light forward. The hinged top of the lamp has a screw fastening instead of the more usual swivel catch.
(See description of No. 1.)
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No. 6. |
CONSTRUCTION.
The pattern is normal Davy, the special features of the lamp being the copper gauzes and the bull's eye.
This is a "dialler's" lamp. It is made entirely of non-magnetic material so that it would not influence the needle of the dial.
The "bull's eye" would provide a better target for the dialler to sight on to in addition to giving a more concentrated beam of light for reading the dial.
No. 7.
TIN-CAN DAVY LAMP.
Presented by J. Straker-Nesbit.
CONSTRUCTION.
This is a normal Davy lamp with 5 ins. gauze, with a quite separate tin-can so made that it can be embodied and locked in position. The bottom flange of the can fits between the oil vessel and bottom ring of the lamp so that when the oil vessel is screwed home the can is secured. The locking is by a screw lock from the oil vessel to the bottom ring.
The can has a three inch high window throughout the entire circumference.
The lamp has a top of rather unusual design for Davy lamps.
(See description of Nos. 1 and 4.)
No. 8.
TIN-CAN DAVY LAMP.
Presented by Christopher Heaps.
CONSTRUCTION.
This is a very rare modification.
The tin-can and the lamp are embodied as one unit, the gauzes being held in the top of the can and lamp standards being redundant.
Gauze. 6 ins high 28 mesh.
Lock. Screw.
Ventilation. Intake air enters through the series of holes in the tin can three inches from the bottom of the lamp. The air is then deflected downwards between the can and an inner partition of ? ins. less radius and which extends round half the circumferences. The air passes from under this partition through the gauze to the flame. The products of combustion escape from the top of the lamp. This shows an early attempt to guide the intake air to the vicinity of the flame.
The window extends round half of the circumference.
This lamp is quite rigid, gives good protection of the gauze from high velocity currents or accidental blows and is an excellent example of a Davy lamp modified practically to its limits, without losing its real character.
(See description of Nos. 1 and 4.)
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No. 9. |
CONSTRUCTION.
This is a surveyor's lamp, it being made of brass with a copper gauze and therefore non-magnetic.
It is a good example of a composite Tin-can Davy.
(See description of Nos. 1 and 4.)
No. 10.
DAVY LAMP.
Presented by T.E. Foster.
Includes Waring's Patent.
This lamp has a most ingenious safety device.
On the top of the oil vessel is a spring lock which acts in such a way that as the oil vessel is screwed on the lock catches behind an extension of one of the lamp standards. To dismantle the lamp this spring lock is depressed by a snuffer which is pulled down by means of the wire handle under the base. The lamp, therefore, cannot be dismantled without extinguishing the light.
No. 11.
IMPROVED DAVY LAMP.
Simplex type.
CONSTRUCTION.
This lamp is a development of the embodied Tin-can Davy. It has a single 28 mesh gauze and its unusual features are (a) the total replacement by glass of the tin of the Tin-can Davy, (b) its elaborate brass top so made that the products of combustion have an indirect passage before reaching the outside atmosphere and (c) the air inlet holes in the bottom ring, which could be closed by means of a slide when it was necessary to extinguish the flame.
HISTORICAL NOTE.
This is certainly a rare specimen and is possibly unique. It certainly has not been in regular use in a mine. The maker and date have not been traced to date. Comparison with similar features in other lamps indicate that it was probably made late in the 19th century.
No. 12.
"JACK" DAVY LAMP.
Presented by Christopher Heaps.
This is a standard Davy lamp with the addition of an external glass cylinder, a type which was commonly used in the North of England from about 1850. The glass fits on to a collar projecting 1/4 ins. above the bottom ring, small holes below the collar allowing for the admission of air.
The addition of the glass was to increase the safety of the lamp in high velocity currents of explosive atmosphere.
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No. 13. |
CONSTRUCTION.
Gauze. Single 36 mesh with cap, slightly conical. The gauze, with
brass ring at the base, screws in to the oil vessel.
Standards. Four standards (C.F. British three).
Lock. A simple form of ratchet and pawl under the middle ring, with
screw.
Wick Control. The wick can be raised or lowered within limits by a toothed wheel which is controlled by a rack under the bottom ring of the lamp. So by turning the top of the lamp (relative to the oil vessel, a movement limited to 90°) the wick can be adjusted.
HISTORICAL NOTE.
The Belgians and French did most important work in the development of safety lamps. The Davy lamp was quickly adapted in Belgium France and Germany and as early as 1818 an official instruction was issued in Belgium regarding the use of the Davy lamp. In Germany also in
The following page is missing from the catalogue.
No. 14.
SCOTCH DAVY LAMP.
CONSTRUCTION.
Gauzes. Cylindrical, 2 ins diameter.
41/2" high with conical top, a double gauze 1 ins. in depth at the
peak.
24 mesh iron.
Light. Candle.
HISTORICAL NOTE.
This lamp, though commonly called a Scotch Davy, (sometimes the Haystack) was not designed by Davy. As he was generally regarded as the inventor of the safety, it was common in some districts for nearly all safety lamps to be called Davy lamps. Some were worthy of him but the Scotch Davy certainly was not. Many miners, early in the 20th century generally spoke of three kinds of lamps, viz. The 'Divvy' (Davy), the 'Geordie' (George Stephenson) if the lamp was of the Stephenson type, and the ''Jennie''(Presumably derived from 'Clanny') for all lamps which had glass but no gauze round the flame.
The original designer and date of origin of the Scotch Davy are not known but such lamps were commonly made and used, in Scotland particularly in 1850.
The lamp is not nearly so safe as the Davy and was introduced chiefly for extra illumination at the shaft bottom, siding etc., where explosive atmospheres would be less likely.
Several explosions were caused by these lamps, however, and the 1886 Commission disapproved of its use.
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No. 15 |
CONSTRUCTION.
Gauze. Cylindrical 53/4 ins high. 31/4 ins diameter, conical top with double gauze at peak.
23 mesh.
Body Work: Copper.
Burner: 1 ins. flat wick.
(See description of No. 14.)