1936-02-08 — Page 2

Page

MARINE ENGINEERING

FAILURES

The services rendered to mer-

indefinitely Thus, Inglia and

HONG KONG DAILY ER

SATURDAY, FEBRUARY

1936.

AND

BUILDING

ENGINEERING

cantile shipping by the British Lake, testing mild steel pieces. THE FIRST THROB

Classification Societies" are. Lap preciated throughout the world, by owners as a basis for security,

'found that the endurance Umit ir bending was reduced from about 17 tons per square inch in

by builders AX À basis for pro- air to a less than 26 when the Boilers Of The Queen

engineering

·gressiva "practice and by theore... tical men as a basis for`analy- tical studies that may assist and support progress in marine and in wider Belds of practice. The paper delivered on the 10th of this month by Dr. S. * Dorey to the Institute of Marine Engineers, on "Marine Machinery Defects—Their Causes and Prevention," is; therefore, of widespread importance to en gineers. The paper deals with the defecta: most commonly: ex-. perienced in heavy forgings used in marine reciprocating engines ur for propeller shafts, of which fatter no fewer than 46,473 were examined by Lloyd's hülyeyors during a period of ten years. As result of these examinations 1.483 propeller shafts were cop- demned on account of erdekk-dé- tected in different stages of deve

ugment, in addition to 204 shafts that were already broken at the time of the examination, making A total humbet df renewals equal to 3.83 per cent, of the number examined; the agures flustrat the need for regular periodical survey.

CRACKS

The cracks found in propeller shafts occur in biost casos in the cone provided to carry the pro- peller, starting very commonly from the keyway. Many start, however, from the ends of the After bronze liner, and a number in the shaft of uniform section between the two liners in way of the item tube, or under a single lunger liner that is not water- tight. Twenty years ago, such fractures were stil regarded as * wholly mysterious" although means had long been employed to exclude water and thereby prevent undue corrosion. Gracks

this kind are now ascribed with confidence to the conjoint chemical and mechanics) action first investigated by the British Admiralty in 1918, and now gene- Tally known

"'corrosion- fatigue." In the presence of water carrying oxygen in solu- tion, steels and other metals are tracture under ranges

. Ilable

ng

of stress much smaller that would be required to start cracks in the same metals in air, drie research has indicated that un- der corrosion-fatigue conditions there existe probably no "tafe" limiting range ofg stress which a particular material can endure

ELECTRICAL MANUFACTURE

A British Record In Employment

Better conditions in Britiali trade and industry during 1935

tests were carried out in River Tees water and were continued, to

58 million cycles. In such

circumstances safety cannot be ensured by more increase of dimensions

CHARACTERISTIŲ FEATURE. Many of the characteristic features

of corrosion - fatigue, cracking: are clearly flustrated in the interesting photographs, re- produced in Dr. Dorey's paper. When the cracks originate in a part. äf the shaft that is of uni- “ form diameter, for example bet- when two liners or, under a liner

: action is due to torsional vibth- tion, the surfaces below (such helices correspond to the princi- pal planes" on which the tensile with maximum

W

Mary Lit For First Time

A thin wisp of smoke from the foremost of the three funnels of the Cunard-White Star Ener Queen Mary indicated to Clyde" bank last month that the liner had at last come to life.

The liner took aboard fts, first consignment of turbine lubricat- Ing all, pumped, from railcar tanks a "liner that is leaking, they ap-on, the quayside, and a reporter pear first as small crosses and

was told that three of the Queen gradually extend, along helical Mary's twenty-seven bollers would lines on the surface. If the be "bolled out," Steam was raised in the auxilary boilers to pro- vide lighting and heating through out the ship from her own plant on Dec. 11 Tests were there after carried out on the seven turbo-generator sets, which will be capable of developing 10,000 10 watts the greatest power station afloat, suficient to supply light ing and public service for a town the size of Aberdeen or Brighton. The boilers for the main pro- peller units will not be lit until late January, so that machinery tests with the propellers uncoup les will Hot be practicable until

.¡ act

stresses values, 14.11 were due to bending, such helicoidal surfaces would correspond to maximum shear stress. The appearance of these helices is now generally regarded as indicative of severe torsional vibration when the helices run in both directions or less severe tor- sional vibration in combination in combination with driving tor- que when the hellces run in one direction only. The directions ofthefi, clacking are innuerced in & marked degree by stress concen- trations due to Hoüidéra or key- ways; cracks. however, are found. sometimes to run transversely in parts remote from stress "concen- trations and the action is then attributed to bending. Thus the direction of chacking often affords a serviceable clue to the source at the trouble...

Dr. Dorey gives valuable statis- tical analyses of the incidence of corrosion-fatigue cracking in pro- peller shafts with different types of liner in way of the stern tube. It appears that cracking is re- latively twelve times as frequent in way of the steth tube when two separte bronze liners are fitted as when a single long Brier is provided to cover the whole length, of the shaft in the tuber The relative frequency is still further reduced to less than one half when oil-retaining glands. are installed without iners on the shaft. The contrast revealed in these figures appears to be of considerable scientint Interest as well as practical value."

DIESEL-ENGINED

SPEED RECORDS

Wheel Lost At

104 M.P.H.

Six Diesel-engined "car records were broken, including the hour

THE MEASUREMENT OF STREET SURFACE BRIGHTNESS

VALUE

The brightness of any point on cent. Il consists of a rectangular a surface is not so stable a quan- metal box with a long horizontal tity as the flumination and must window through which the ob be distinguished from it. It de server looks at the street. He pends upon the amount of light then sees superimposed on the reaching the surface, the direc view row of "amail sputs of m- tions from which that light comes, cressing brightness. These spots and is viewed, and the reflecting are formed us patches of allver- properties of the surface, which, ing on a ginss allde, by reflection in turn, vary with the smoothness from a translucent window which and dryness. It can be expressed is illuminated by a small lamp a0 as the intensity (candle-power) as to be brighter at one end than emitted per unit area, Lean the other. candle power per square inchp per square centimetre, the latter whit being known as a "stilb. 1 can also be expressed as an equi valent illumination, this is by saying that the brightness is equal to that of a perfectly matt object receiving a stated illumination and having a reflection factor of 100 per cent, This unit is either call ed lambert," orie-thousandth of which is nearly equal to an equl valent roof candle or an "apostlib." which is equal to an equivalent .metre-candiễ

BRIGHTNESS

the spots can be read off on à

The value of the brightness o scale. Having selected the point on the road surface of which he. desires the brightness, the ob server looks at this point with

one eye, at the same time moving spot the brightness which is as the Instrument until he finds

of the test point. The lamp is dearly as possible equal to that

supplied from a small dry bat- tery through a variable resta tance, which can be adjusted for ranges of 0.2, p. 0.8 equivalent Measurements of brightness are foot-candles and 0.002 to 0.08 very useful on street-lighting in- equivalent, foot-candies. A blue tallations, for they enable palu- filter is provided for use with able: conclusions to be drawn, as tigh-pressure mercury - vapour to the visibility, and the "best lamp installations, *- TRIP TO THE SEA

methods of improving it; even "When the measurements are A though the actual figures are not being taken it is advisable for the Elaborate, precautions are being of high precision. These mea- observer to stand about 10 ft. from taken to ensure that the ship does surements "an be made by mat the near-side curb and to pay not meet with any accident on ching the brightness of which the particular attention to readings her dificult 15-mile journey from value is required against a know at the positions against which the Clydebank fitting-out badn to brightness, and this is the method objects will be seen when they the Tall of the Bank, Firth of used in the brightness meter are 150 ft. to 300 ft. ahead of a Clyde, where she will await her manufactured by Messrs. The car, as the "effective" brightness trials.

General Electric Company, Limit- thus obtained has a large effect ed Magnet House, Kingsway, on the determination of the yat London, W.C.2.

bility. It should be noted that. This meter is a simple visual changes caused by variations In photometer, designed for street the lighting equipment and la

Warning of the fouling of any obstruction on the way will be au- tomaticaly signalled to the bridge by a sensitive apparatus, which is to be placed under the ship."

Though the journey will take only about five hours, it will be done in two stages, so that the best of two succeeding tides can be used.

ing work and capable of the character of the road surface ving readings within 20 per may affect the conclusions drawn

Between the tides the Queen Mary SCIENCE AND NEW

will lie at an old Admiralty Wharf at Old Kilpatrick, which will be extensively reconditioned for the occasion.

It is estimated that at the old Kilpatrick bend there will be only about 10ft clearance between the river bank and, the liner's propel ler blades. To make her as light as possible all but two of her life boats wil be towed to the Tall of the Bank

and

The two pilota Mr. Cameron

Mr. Murchie

who supervised the canting of the Queen Mary into the atung out baslp after her

launch, will, agath be in charge.

THE NIZAMSAGAR DAM, INDIA

The Nizamsagaz irrigation dam has recently been inaugurated by the Nigam of Hyderabad It 1 capable of Impounding 30,000 depth of 108 ft at the dam site, and will form a lake "spreading over an area, of nearly 50 square

BUILDING MATERIALS

In the course of an address which was delivered at a confer- ence held at the Building Re- search Exhibition in Manchester, Dr. R. Stradling said that the traditional knowledge of the building industry was craftsman- ship designed to meet the human" needs of protection chierty from the weather. To apply scientific research to such an industry was thugs that had to be done was not lasy. This, one of the first

not easy. Thus, one of the first things that had to be done was to Tedge which had Beed m translate the traditional know- mered on by practical experience into salentine terms, and to do this was render- daftsmen carried out so much of their work instinctively, But un

complished it was almost impos-

were reflected in greater activity record at 103.01 m.p.h, by Cap milion Cup ft. of water with ed more timcult by the fact that

in electrical engineering, and it

is encouraging to note that more. persons were employed in elect- rical manufacture during the 12

tain G.ET. Eyston at Montihery, before the loss of a front wheel brought the run to a dramatic

finish. At the time the car was miles in which there were former: All this translation had been ac- months than at any other time doing over 104 m.ph, and it was 1y 49 villages. The 98 miles of sible to judge whether new ma-

only the skill of A. Denly, Eyston's co-driver who was then at the wheel that kept the car on the

track

in its history. Furthermore, ex- ports, of electrical goods and apparatus rose by over 22 per cent compared with a corresponding

Capt. Eyston had set out to est- period of 1934.

One of the most satisfactory with his AEC-Diesel engined ablish 100 m.p.h. for 24 hours features in relation to generating streamlined saloon, and when, the plant is the wide demand which has been experienced by the lead attempt came to an end had cit Ing manufacturers. Apart from ablished worlds records for 50 large turbo alternators, such as kilometres at 98.88 m.p.h., 50 those of 62,600-kVA being erected miles at 101.24 mp... 100 ko- for the Rams Hall Power Station metres at 101.82 m.ph., 200 kilo extensions at Birmingham and metres at 103.21 mph., and 1

hour at 103.01 m.ph. large machines for Palestine, South Africa and other countries. the General Electric Co., of Eng land, have found that the demand for somewhat smaller machines has broken all previous records and, in fact, is practically world- wide.

It is interesting to note that the AEC.6-cylinder oil engine used fo almost standard with es PG of the makers output and is aimilar to the type employed in London's buses.

pleted during the year for a Sher- held firm, for example, included four large motors with total ca- pacity of about 1,000 hp.

main and branch canals, together teals and preparatons were, good with distributaries aggregating or bad. The techno about 1,100 miles, irrigate 215,000 crattamen had been developed on

acres of land, Of these, 20,000 acres will be under sugar-cane al material would not change. assumption that the tradulon-

and the remainder under rice.

ARTIFICIAL DAYLIGHT

The variability o of dayught at different times of the day, feasons of the year and in different parts of the country has the effect of making accurate matching dim cult. It is claimed that this im- culty can be overcome by asing the Claudegen system of artificial daylight, devised by Mesars. The General Electric Company Limit ed, Magnet House, Kingsway London WC2, since this pernilt an absolutely constant standard or light, and thus a constancy of appearance of colours of the same nue, to be obtained. It is also stated hat sensh

Outdoor oil circuit breakers of 1,000,000 kVA, breaking capacity are being manufactured for ex ea port to Palestine and New Zea to tre land

ELECTRIFICATION Industrial electrification has been extended in all directions, in particular, there has been a continued demand from South Arca for mining plant. As an example, this same company is instaling equipment in one mine at a depth of 7,000ft. Again, wind ing equipment for the mines of the International Nickel Co. of Canada includes three 1200 hp direct current motors. Then further schemes for the reor alai ganisation of the iron and steel - ber Industry at home have, brought tath about a demand for large electrio rolliak min equipment; oile com-

An extensive contract covering a complete power station, hat ling

the

port

Coal For

than

texture

#blemfaner

This was not true, for though a substitute might be perdectly good for certain purposes, It might prove a failure the way It disturbed thi niqué.

tech-

MEXTURE OF FLASTER

For instance a certain mixture. of plaster and lime was recom mended for use on a new house

the proviso, that only small be mixe

Economic Private Generation

The Electrical Review, has pub- listed under the above beading an Interesting account of the power installation and load at the Works of Messrs. Kelly's Directories Ltd., Andover. This fine Power House has been described previously in these columns, but we think many of our readers will be interested in the details given below, of run- ning costs for a typical recent. week

The plant worked on the high- ly unfavourable load factor of K.WH. with 209 engine hours run- 9.6 per cent, generating 9181 ning and a maximum load of 290- KW Costa per K.W.H. generated were as follows

Fuel Qu

4305d Lubricating, all .... 0:0970. Wages:

0.095EL Stores and Repairs 0.0134.

DEPRECIATION

0.5100.

Nothing has been allowed above for depreciation of plant and pre- dient to show once again that the mises, but the figures are sun-

Petter Atomic Diesel will generate current at augure comparable

fains" supply and vestigation umally proriounced saving m the case of Messrs. Kelly's Dir- tories Ltd the work's load is highly erratic, and the re sets installed rere carefully chosen on account of the ease with which the loads ald be widely dusting prit

was used for light

AND

GEMENT

EMERALCRETE

RAPID HARDENING

PORTLAND

CEMENT

IN PAPER BAGS OF 94LBS NETT

PRODUCT OF

GREENSLAND CEMENT CO.LTD.

EXCHANGE BUILDING. HONG KONG

THE TAIKOO DOCKYARD & ENGINEERING

COMPANY OF HONGKONG, LIMITED

BUILDERS OF ALL CLASSES OF SHIPS. – BUILDERS OF RECIPROCATING STEAM ENGINES. BUILDERS OF MARINE AND ILAND BOILERS, BUILDERS OF TURBINE MACHINERY

Under License From Messrs Parsons. BUILDERS OF DIESEL ENGINES

Under Special License

From Messrs. Sulzer Bros., Winterthur. Licensed To Manufacture

Lanz Perlit Iron, Specially Suitable For Internal Combustion Engine Working Parts. DOCK & SLIPWAYS

FOR DOCKING VERY LARGE CABINELL AS §MALLIR VERBETE.

ON ANY TIDE ALL CLASSES OF SHIP, ENGINE AND BOILER

REPAIRS AND EXTENSIVE WELDING BOTH ELECTRICAL AND OXY- ACETYLENE SKILFULLY AND PROMPTLY CARRIED OUT.

BUTTERFIELD & SWIRE, Agents,

HONG KONG, CHINA - JAPAN.

Hone Koso

CALL TLAB NVIDIAE DES MOVER – PEWNANT Aza,”

SPEED EASTWARD

FROM SEATTLE IN

SOLID COMFORT

ON THE

COMPLETELY

CONDITIONED

Olympian