ilp archive : journals
public lighting no. 11 vol. 3: special conference number
- At Bournemouth: A Trail Of Brightness p59
- Summary of of the lively debates and events at the Fifteenth Annaul Conference
Of Public Lighting Engineers. The "Lambeth Walk" was particuarly enjoyed at the
- APLE: Conference
- Bournemouth's 5-Year Programme p60
- Capital expenditure for street lighting planned for Bournemouth over the next five years.
- Lighting: Installations
- The G.L.I.S. p60
- The General Lighting Intelligence Service was instituted by Mr. H. L Juliusburger
of Ladbroke Grove in 1937. It offers up-to-date information as to the development of the lighting world,
both in the UK and places abroad. It has already produced eight issues. The statistics offer a useful form
of comparison for lighting engineers, manufacturers and others interested in the actual production of street
- Lighting: Publications
- The Fifteenth Annual General Meeting p61
- Notes taken at the meeting which was held at the Town Hall, Bournemouth on Monday 5th September 1938.
- The membership was increasing at about a rate of one per week.
- The Annual Report was appraised but members had to send in accurate figures if it was to be of real value.
- Special mention was given to Mr. Wilkie for the Education Scheme and
Mr. Lennox for calculating costs if the MOT Report was adopted. (The latter
included the collation of thousands of figures, and a huge schedule had be prepared relating to 30 cases,
which had been sent to the MOT).
- The Minister had suggested that any lamp columns erected on trunk roads should have the approval
of the Fine Arts Commision before the Ministry would pay a grant. Therefore all
"steel and concrete people" had been approached by the APLE for drawings and these were put to the
Fine Arts Commission that month.
- The association was £180 in credit, with a balance sheet of £687.
- The first lighting scheme under the Trunk Roads Act 1936 would shortly be installed
after negotiations between Earley Parish Council, Berkshire County Council and the MOT. Sodium lighting
was chosen which would cover a mile of the London Road through Earley to the outskirts of Reading. It
would consist of Philora sodium lamps in ELECO GoldenRay fittings.
The opening ceremony on October 17th was going to be attended by a large gathering of representatives of
the highway authorities and various Associations concerned with lighting, road transport and road safety.
It marked the first direct financial assistance by the Government towards securing greater road safety
through trunk road lighting.
- APLE: Organisation, Lighting: Design, Lighting: Installations
- Opening Of Exhibition p62
- Brief details of the opening of the exhibition.
- APLE: Conference
- The Presidential Address p63
- Summary of the The Presidential Address.
- APLE: Conference, Lighting: Education, Lighting: Floodlighting,
Lighting: History and Lighting: Specifications
- The M.O.T. Final Report p64
- Summary and discussion of The MOT Report.
- Points raised during the discussion: The tendency in the future would be to increase both height and spacing
eg. 35' and 250'-300', there were too many posts for lighting dual carriageways, in every sharp bends a catenary system
could be used; a committee of the British Standards Institution was now dealing with a standard specification
for street lighting which would shortly be published, there were too many posts for lighting dual
carriageways which was not good for economy or aesthetics, the MOT Report was of little use unless
new administration of public lighting was introduced into the legislation i.e. it was 0.3d of the £ for rates in
large cities, 3d. in the £ for small towns and and 1s in the £ for remote districts, street lighting should
be part of ordinary highway costs, it would cost £3 million - £5 million per annum to carry out the
recommendations in the Report and this was beyond local authorities - this money could be obtained
if account were taken of the cost of accidents and there was a tax of 5s. per annum of bicycles;
many towns owned their gas or electricity undertakings, but many did not want to spend money, and
stated that the MOT Report was not mandatory but was a recommendation and so did not follow it;
the MOT Report was not a yard-stick with which to measure the excellence of street lighting - this was good
as the excellence of any installation was a matter of judgement, and the MOT Report indicated the general
lines on how to obtain an efficient installation, the important thing was proper siting as then the
equipment was given a proper chance; hours of lighting was not mentioned, except for dusk to dawn, and
the lighting of different configuration of streets would be better achieved by light actuated controls;
the lighting of double or S bends wasn't clearly specified as there should be overlapping of the
lamps at the junction of the two bends; the Departmental Committee didn't contain any member who bought
public lighting, although it contained many who made and sold equipment, the report dealt principally
with main roads but 80% of the population lived in narrow roads, grants were only to be made for trunk roads
and not other roads; illumination should not be measured but darkness, and greater attention should be
given to the diversity factor, the tendency was of manufacturers to make miniture searchlights and to
throw intense illumination on a given spot.
Reply: Mounting height of 25' primarily dictated by maintenance. The MOT Report in itself was a very good
yard-stick. There should be overlap at the junction of two bends. The lighting of roundabouts required more
attention. He hoped the MOT would provide more grants. As for diversity, if all the recommendations were carried
out then there would be good uniformity of visibility.
- List Of Exhibitors p66
- List of exhibitors both inside the conference and outside on the roadway by the Exhibition Hall.
- APLE: Conference
- Air Raid Precautions And Lighting p67
- Summary and discussion of Air Raid Precautions And Lighting.
- Points raised during the discussion: The public could get accustomed to a state of continuous darkness, but switching
lights off just before an air-raid might lead to lower morale; what was central control: was it the whole of
an area administrated by one lighting authority or an area of supply?, regarding switching lamps during
fog, unfortunately fog paid no attention to local boundaries; the real point of controversy is whether lighting
should be extinguished upon receipt of a warning and brought into operation immediately after the raid, or
whether throughout the period of hostilities all lighting other than specially arranged traffic signals should
be eliminated; to extinguish all lights during an air raid would create more panic and chaos than would the actual
falling of bombs; it was up to the manufacturers to devise a system of control of street lighting
during air raids which would show up kerbs and generally permit pedestrians and traffic
to move with a reasonable degree of saefy.
Lighting: ARP and Lighting: Control
- The Bournemouth Gas And Water Company Entertain The APLE At Luncheon p69
- Details of the luncheon and the speeches.
- APLE: Conference
- Public Lighting By Gas In Small Towns p73
- Summary and discussion of Public Lighting By Gas In Small Towns.
Additional information was given about the lighting of Denton and
lighting of Ormskirk, the MOT Report making lighting unaffordable
for villages and small towns, and the instantaneous extinction of gas lighting lamps - it is possible to
turn them off with a pressure wave control
Points raised during the discussion: Lighting authorities should get together and try to find some joint
consultative means instead of consulting services, the gas industry was too prone to put in schemes which
were just slightly more than the 3000 lumens per 100' linear (whilst electrical schemes were prone to use
5000 lumens), many local authorities did not light their areas, especially side streets, adequately,
square lanterns could be used for the lighting of side streets if proper refracting and reflecting
surfaces were used; gas industry had centralised control many years before it was applied to electrical
methods; the whole of the street lighting in Berlin (gas and electric) was controlled according to the
natural illumination prevailing and they were relying on total extinction during air raid periods,
siting was far more important than lumen output; the paper should have expressed opinions of whether electricity
was better than gas [he was reminded that this was not the function of the Association]; the
consumption of by-passes was queried, the ARP requirements were also questioned (as one department suggested
lamps to be used during an air raid whilst another department stated there would be no lighting); no consideration
had been given to government finance to "service roads" along the main roads; the installation at Denton
was the best low-pressure gas lighting system anywhere; cost was one of the biggest difficulties but not
best use was made of the lamps now arranged; lighting was required after air raids as curiosity would bring
a large number of people onto the streets, the pressure wave control system in Burton worked at 99% which
surprised many engineers; for one local authority the penny rate brought in £30 and there were five miles of
road to light and another brought in £50 for three miles - it was obvious that many local authorities could
do nothing to improve their street lighting - the Home Office or Ministry Of Health should make grants -
and 90% of the traffic which used those roads never paided a tax or rate in that district, the 7000 or 8000
lumens in the MOT Report was unncessary as 4000 lumens could do the job as well; could contracts made for
10 and 15 years be changed as progress was made, the average engineer and surveyor could do the job of a lighting
engineer quite well for a small council; by-passes burned 6 to 8 cu. ft. per day, planning for ARP Lighting
should be directed by the Home Office; one of the objects of the United Kingdom Gas Corporation was to
provide a consulting service for small authorities especially as modern developments required specialised
attention which small gas undertakings could not give; schemes were designed to deliver just over 3000 lumens
per 100' linear as local authorities could not afford 5000-6000 lumens (either gas or electricity), side road
lighting had been neglected and the MOT Report added to that neglect as it focused on main road lighting,
lumens output was not criterion of efficiency and siting and positioning of lamps was more important, all
gas contracts of 10 and 15 years were reviewed each 5 years.
Lighting: ARP, Lighting: Authority Organisation, Lighting: Control,
Lighting: Funding, Lighting: Installations, Lighting: Luminaires and
- Conference Reflections p76
- Summary of the Conference, the papers, events and hospitality. The papers themselves were summarised in
this issue as there wasn't space to include them all; bound copies of the papers could be purchased from the
- APLE: Conference
- Eastbourne And Evolution p77
- Summary and discussion of The Development Of Street Lighting In A Country Borough.
Points raised during the discussion: The subject of gradation of light was poorly handled by the MOT
Report and caused confusion, the lighting of bends was still problematical; comparing mercury and sodium lamps
could be difficult as each had its advantages and disadvantages, it was an excess of candle power at the horizontal
which was far more important than the intrinsic brightness of the source, therefore when comparing different
light sources, the light distribution and mounting heights and planning should all be similar; a fixed policy
for street lighting should be congratulated, it was necessary to light for motorists and pedestrians (which
some discharge lighting enthusiasts ignored), the daylight appearance of fittings should be given more
attention in industrial towns; a method for improving the power factor of low-pressure sodium lamps was
suggested; glare was an important factor and should be considered, distribution was related to spacing and
not to glare, the comparison between sodium and mercury was not fair as a scentific fitting was used for sodium
whilst a decorative fitting was used for mercury; the lighting of open spaces was not considered; gradation
in the MOT Report suggested that if a motorist moved from a well-lighting main street to a well-lighted road there
should not be gradation, just because the MOT Report did not recommend something it should not be tried,
comparisons of sodium and mercury had been carried out by questionnaire and the replies were honest,
tests showed that 10% of light output was absorbed by dirty fittings and in Eastbourne the fittings were
cleaned every six weeks.
- Lighting: Colour, Lighting: Columns, Lighting: Control, Lighting: Environment,
Lighting: History and Lighting: Installations
- Technical Photography p83
- Summary of the exhibit of technical photography by Hobbs, Offen and Co. Ltd
- Lighting: Photography
- Special Roots For Tubular Columns p84
- Diagrams of the various special roots supplied by The Bromford Tube Company Limited
for their tubular steel lamp columns.
- Lighting: Columns
- Radiation From Artificial Illuminants p87
- Summary and discussion of The Radiation From Artificial Illuminants.
Points raised during the discussion: very power internally modulated lamps could be mounted at heights of
half-a-mile or a mile high with only one or two lamps used to light a whole town; there was now
very much less objection from the general public to the colour of the lighting when using electric
discharge lamps, the main object of street lighting was visibility, the time was not far distant when
much higher mounting heights and longer spacing would be possible and give the visibility required
at a cost within the money available; had the pheonomena of luminescence been investigated as an
option; internal moduled lamps were designed for different purposes and had very different lives
from that required for street lighting, Telsa had attempted to light a city in the USA by means
of poles hundreds of feet high with arc lamps.
- Lighting: Lamps
- The Annual Dinner p90
- Details of the toasts, speeches, the King's telegram and formal addresses.
- APLE: Conference
- Progress In Electric Street Lighting p90
- Ten years ago electricity was responsible for less than 40% of the total lighting of Britain's highways.
Now it is 60%. The reason is that ten years ago the average cost of electricity for street lighting was
nearly 2d. per unit - it is now 1.107d. per unit. Additionally due to the improvement of electric light sources,
the 1d. can provide four to five times the light that could be obtained ten years previously. Furthermore
the adoption of the MOT Report by many authorities has led to a 4000 hour lighting season (dusk-to-dawn all
year) which results in comparatively little increase in cost with electricity and the relatively inexpensive
maintenance of electric street lamps.
- Lighting: Comparisons
- Bath Road Lighting Scheme p90
- Details of the Bath Road installation near Hayes which was
the first installation in accordance with the MOT Report on that road.
- Lighting: Installations
- The Lighting Of The Frankfurt Streets Leading To The "Reichsautobahn" by Ernst Rothe, D.L.T.O. p91
- A translation of an article from "Das Licht" published on the 10th March 1938. The building of the
German Motor Roads, which was commenced on the 23rd September 1933, when the Fuehrer removed the first
turf, prompted many towns to build a main entrance road to the "Reichsautobahn." About four years ago
the town of Frankfurth-On-Main built the road for heavy traffic stretching from Frankfurth to Mainz and
Wiesbaden when leads to the Reichsautobahn. The old lighting standards looked out of place - from
both technical and architectural points of view. The lighting was effected by means of flat beam reflectors
fitted with 150' lamps, the light source being 8 metres from ground level, the wooden poles spaced at
60 metres. The Frankfurt Town Council then decided to erect new lighting standards. Sodium vapour lamps
were selected. A stretch of road 1.5km was built - it was 10 metres wide with, on either side,
a green grass track, a row of poplar trees, a cycle track, a path for small carts and a footpath, so the
total width is 65m - however only the heavy traffic part is lighted up. The lamps are 160W, 11,000 lumens
output, mounted in the centre of the road, being 10m above ground level, and spaced at 44m. The distribution
of light is effected by means of enamel reflectors 2x75° diffusion angle. The driver has 100 meters
effective visibility. As it is the only lantern to use sodium light, the yellow colour serves the purpose
of showing the people the way to the "Reichsautobahn" - other new roads use incandescent only to avoid
confusion. Poles had to be 11.5m tall with a pull at the top of 300kg. The so-called "Stahlpanzermast"
(Adastra Sectional Steel Poles) were selected - these poles had already been used
in various towns in Germany.
- Lighting: Colour, Lighting: Installations
- A "Philora" Campaign p92
- Philips have issued The "Philora" Plan For Public Lighting.
Good public lighting is envisaged as embracing adequate intensity, reasonable uniformity, lack of
glare, correct siting of units, correct contrast production, reasonable road brightness, low operating
costs and easy maintenance. The booklet sets out the main recommendations of the MOT Report and
features pictures of installations.
- Lighting: Publications
- Lighting For Pleasure Gardens p93
- Description of scheme used for lighting the flower beds in the Pleasure Gardens, Bournemouth. It's a
step-by-step guide on how to make the fittings.
- Lighting: Luminaires
- Illuminating Engineering Syllabus p94
- A definite education scheme has emerged for the recognition by diploma of the status of Public Lighting
Engineer. The scheme was the result of a meeting of a large number of associations, which had drawn up an
advisory committee, and it included an Intermediate and Final Examination. The Final Examination was divided
into Section A (general) and Section B (particular reference to Public Lighting). The regulations and
syllabus were issued by the Department Of Technology at the City And Guilds of London Institute.
The Intermediate Examination will be of a standard which a candidate may normally be expected to reach after
a course of part-time instruction over two years. The Final Examination will require an additional one to two
years of study. Certificates of First or Second Class will be issued for all the examinations. All examinations
will consist of a question paper of three hours duration.
- 1. Light Production And Control
- Radiation from a hot body; the spectrum, visible and invisible.
- Brief description of other forms of light production - luminescence, fluorescence and phosphorescence.
- Electric discharge in gases.
- Reflection (specular and diffused), refraction, transmission and absorption of light.
- Simple polarised light.
- 2. The Eye And Vision
- The eye; physiological optics; sensitivity to intensity and colour; persistence; adaptation; fatigue;
glare; visibility and contrast.
- 3. Photometry
- Measurement of light intensity from a point source.
- Inverse square law and oblique incidence.
- Candle power, units and standards; mean spherical and hemispherical candle power; luminous flux and the
lumen; candle power of sources with diferent colours; polar diagrams including Rousseau diagram and Russell
angles; iso-candle diagrams; globe and other integrating photometers
- Line and surface sources
- The measurement of illumination; British and Metric units; the foot-candle and the lux; illumination
photometers; iso-lux diagrams; brightness and its units.
- 4. Practical Light Sources
- Daylight: qualities; admission into buildings; daylight factor and sill ratio.
- Gas: the bunsen burner; various types of burner; high and low pressure fittings; the incandescent mantle;
composition, properties and combustion of gases; products of combustion.
- Lighting by acetylene, paraffin oils, petrol-air gas, oil gas.
- Electricity: arc lamps; incandescent filament lamps, vacuum and gas filled; vapour discharge lamps.
- Fittings: properties of glasswear; reflectors; refractors; diffusers; globes; shades and the effects
on the amount and distribution of light.
- 5. Illumination
- Effect of degree and nature of lighting in various situations; illumination required for various
purposes; B.S. Specifications; rules for the avoidance of glare; shadow conditions; opportunities for
general and local lighting; direct, indirect and semi-indirect lighting; reflection of light from walls
and ceilings; application of fully diffused and uni-directional light; conditions of colour discrimination;
study of lighting problems in houses, factories and streets; calculations necessary for spacing,
height and positioning of lamps; aesthetic problems and architectural lighting.
- 6. Distribution And Control System
- Gas: High and low pressure distribution systems; remote and automatic control apparatus.
- Electricity: distribution systems; mains; switch-gear; protective apparatus.
- Factors involved in costing; tariff schemes.
- Final: Section A
- 1. Radiation And Light Production
- Radiation: wave theory; quantum theory; line, band and absorption spectra.
- Selective radiation and luminescence: fluorescence and phosphorescence.
- Spectral energy curves: infra-red, visual and ultra-violet; spectral distribution from common light sources
- Influence of spectra on coloured objects.
- 2. The Eye And Vision
- More advanced study of vision.
- The retina; peripheral and foveal vision.
- Sensitivity of the eye throughout the visible spectrum.
- Vision at low intensities: dark adaptation; threshold measurements; Fechner's Law.
- Colour vision by strong and weak light; the Purkinje effect.
- Trichromatic theory of vision.
- 3. Photometry
- Light standards and the full equipment of the photometric laboratory: screening; auxiliary apparatus; sector discs; rotators.
- Special problems of heterochromatic photometery; the flicker photometer; yellow/blue ratio; use of colour filters
- Physical photometers; their limitations and precautions in their use.
- Final: Section B
- 1. Artificial Light Sources
- More advanced study of light source and their equipment
- Mechanical and thermal properties of glasses of various compositions
- Optical properties of glasses and other reflecting media.
- Use of refractors: symmetric and asymmetric refractors.
- Design of projection apparatus; beam divergence, head lights, searchlights.
- Further study of modern gas burners; high and low pressure.
- Further study of electric lamps including vapour discharge lamps.
- 2. Lighting Installation
- More advanced study of the planning of lighting installations.
- Natural lighting; co-efficient of utilisation, room index.
- Calculation of illumination due to point, line and surface sources.
- Design for special applications e.g. streets, factories, workshops, schools, shops, offices, exteriors of buildings.
- Influence of lighting requirements on architecture and building construction.
- Organisation and adminstration of a lighting department.
- Lighting: Education
- Public Lighting Equipment p95
- Brief description of the stands at the conference, and the display on the roadway
outside the Exhibition Hall.
- APLE: Conference
- The "Wask" Raising And Lowering Gears p95
- Brief description of a new brochure issued by Walter Slingsby And Company Limited
- Lighting: Columns, Lighting: Publications
- The "Radiovisor Light-Ray p95
- Brief description of a new booklet issued by the Radiovisor Company.
- Lighting: Control, Lighting: Publications
- Lighting A New Zealand Street 90 Feet Wide p95
- Details of the GEC scheme lighting a street 90 feet wide at Invercargill, New Zealand.
The scheme treated the thoroughfare as two separate streets. The installation, incorporating more than 50
400W Osira lamps, has produced excellent results. Two sets of tramway rails mark the
centre of the street. The lamps, housed in GEC Di-Fractor lanterns,
are arranged in staggered formation in four rows down the length of the street; they are spaced 250'
apart and the mounting height is 25'. The outside fittings are mounted on poles whilst the two middle
rows are suspended on span-wires.
- Lighting: Installations
- Street Lighting Notes p96
- Brief description of the installations at Bedford, Belfast, Bingley, Blackpool, Bridhouse, Burgess Hill,
Calstock, Chatham, Chesterfield, Colwyn Bay, Dewsbury, Edinburgh, Finchley, Fleetwood, Gainsborough, Greenock, Guildford, Gunnislake, Hadleigh,
Haslemere, Hebburn-On-Tyne, Hnely, Herne Bay, High Bentham, Ipswich, Kuntsford, Lanarkshire, Leatherhead, Lewisham, Leyland, Lincoln,
Liverpool, Ludlow, Middleton, Midsomer Norton, Mirfield, Moffat, Nottingham, Oldham, Paignton, Pembroke Dock,
Pickering, Poplar, Reading, Renfrewshire, Ripponden, Romford, St. Helens, Sherborne, Shipley, Slough, South Shields, Southwold,
Stoke-Upon-Trent, Stratford, Tivertoon, Todmorden, Totnes, Troon, Walsall, Wanstead and Woodford, West Bromwhich, West Lothian, Worcester
- Lighting: Installations
- Horizontal Burning Mercury Discharge Lamps in Lancashire p99
- Description of a new installation in Stretford.
- Lighting: Installations
- Floodlighting At Bournemouth p99
- Picture of the Hawthorns Hotel floodlighted with Primrose "Sieray" discharge lamps in
- Lighting: Installations, Lighting: Floodlighting
- Model Illustrating Correct Street Lighting p99
- Description of the model produced by the GEC to illustrate the recommendations of
the MOT Final Report. It consists of two parts - a realistic system of streets bounded by houses, cinemas
and factories. The model measures 5' long by 2' wide, the lighting columns, road and spacing being to a scale
of 1':380'. Running the whoel length of the model is a main arterial road - this is lighted by columns providing a mounting
height of 25'. The two sections of the arterial road, which is divided by a roundabout, is over 40' wide:
this is lit by a staggered arrangement of units not more than 150' apart, with an auxiliary unit centrally
suspended every third position, so that there's no dark central section of the road. After the roundabout
the road is made into a dual carriageway, the central reservation being over 6' broad. Dual carriageways
must be treated as two separate roads, each having a staggered arrangement of lighting points with an average
spacing of 150'. The fact that the central island is more than 6' broad necessitates the use of a column
carrying two lanterns, each lantern being suspended over its own carriageway. Where the dual road bends
away the lighting points become closer and on the outside of the bend only. Branching from the roundabout
is another road which shortly divides into two, the major portion becoming an S bend. Round this bend the
spacing becomes very close in accordance with the rule that says the angular separation between lighting points
should not exceed a certain number of degrees. Other examples include lanterns that indicate to side road
traffic that a main road is ahead; cross-road lighting with lights arranged just beyond the crossing;
and roundabout lighting. The model was installed at Magnet House, London, and could be viewed there.
- Lighting: Specifications, Lighting: Theory
- Two New Devices For Use With Public Lighting Apparatus p101
- Description of light-actuated control for gas lamps and an automatic cut-off for gas lighted bollards. Both
were exhibited by Sugg at the Conference.
- Light Actuated Control
- Used for lighting street lamps between dusk and dawn. A recitified photo-electric caell is fixed
in a suitable position on the lamp and is connected with the main control box. The components in the box
include an electric relay, a 3-volt dry cell and a clockwork operated gas valve which incorportes a
switching device. When daylight falls below a pre-determined value, the current from the photo-electric
cell operates the relay, which allows a small current to flow from the dry-cell to energise an electro-magnet,
which operates the trip mechanism on the clockwork gas valve, which then turns to the "on" position
and lights the lamps. A similar operation occurs when the value of daylight increases to a pre-fixed
value and the lamp is extingushed. It can be used for refuge islands with centre lamp; and for all lamps
and signs on a roundabout. It is possible with Comet ignition to light all lamps up simultaneously.
The only attention required is the winding of the clockwork mechanism - about once every three weeks -
and the renewal of the battery - not more than once per year. The control was patented by
Mr. W. H. B. Hall, Mr. R. H. Whillock and the South Metropolitan Gas Company originally
for use in schools. It was developed by Sugg for street lighting in conjunction with
the Public Lighting Section of The Gas Light & Coke Company.
- Automatic Cut-Off Device
- The possibility of an escape of gas igniting if a gas-illuminated bollard is knocked over was looked at
by the Public Lighting Section of the The Gas Light & Coke Company. They
devised an automatic cut-off valve which is being manufacturered by Sugg.
The valve is fixed to the service in the base of the bollard, preferably below ground level, and the
supply to the burner is conencted to it by means of an easily broken nipple, which ensures the valve
not being broken away from the service if the bollard is knocked down. The device itself is
diaphragm operated, the inlet gas passing to the underside of the diaphragm and thence through a valve to
the burner. The effective area of the valve is small in relation to that of the diaphragm. Pressure at
the burner is conveyed to the upper side of the diaphragm by a small bore tube, and under ordinary
conditions, with almost equal pressure both above and below, the valve is kept open by its own weight.
Immediate fracture of either the main supply or the small bore tube, the pressure above the diaphragm
is reduced to atmospheric, and the inlet pressure snaps the valve shut and keeps it in this position
until pressure is again applied above the diaphragm by means of reconnection. Owning to the success of
this device, it is now being fitted to all gas lighted bollards and guardposts.
- Lighting: Control
British Commercial Gas Association,
William Sugg And Co., Ltd.,
Walter Slingsby and Co., Ltd.,
Siemens Electric Lamps And Supplies Ltd.,
The British Thomson-Houston Co. Ltd.,
The Horstmann Gear Co., Ltd.,
Public Health Service Exhibition And Congress,
British Electrical Development Association, Inc
W Parkinson And Co.,
Engineering And Lighting Equipment Co. Ltd.,
Johnston Brothers (Contractors) Ltd.,
Bromford Tube Co. Ltd.,
Stewarts And Lloyds Co., Ltd.,
General Lighting Information Service,
Radiovisor Parent Ltd.,
Metropolitan Vickers Electrical Co. Ltd,
British Sangamo Company Ltd.,
Hobbs, Offen And Co. Ltd.,
Gas Meter Company,
Foster And Pullen Ltd.,
REVO Electric Co., Ltd.,
James Keith And Blackman Co., Ltd. and
The General Electric Co., Ltd.