1931-09-05 — Page 2

Use Green Island Cement

for

Constructural Work of Every Description.

HOW GREEN ISLAND CEMENT IS MADE

Green Island Cement is manufactured from hard limestone and clay. It is necessary that these materials should be finely ground in order that they may come into intimate contact with one another in the burning process.

The finely pulverised materials are mixed in a certain definite proportion, roughly one. part of clay to three of limestone, and are fed to the Rotary Kilns.

In these kilns they meet the hot gases and flames generated by pulverised coal blown in at the other end of the kilns, and after various chemical actions have taken place, they combine. to form Portland Cement Clinker.

The Olinker is ground down with a small percentage of gypsum to regulate the setting time, and Green Island Portland Cement is thus produced.

Although sounding so simple, in reality the process is an intricate combination of mechanical, physical and chemical operations, needing great skill and care. Nothing but constant and accurate supervision will yield the results so. well-known with Green Island Cement, namely, strength, uniformity and reliability.

USE GREEN ISLAND CEMENT

Issued by the

GREEN ISLAND CEMENT CO., LTD.

2ND FLOOR,

EXCHANGE BUILDING.

STRUCTURAL STEELWORK

OF OUTSTANDING CHARACTER

THE NEW TINE BRIDGE, NEWCASTLE

The Arch has a span of 531 feet and contains 4,000 tons of Steel. The approaches contain a like amount.

to the methods, of erec- Owing tion adopted, both road and river traffic beneath the bridge-were uninterrupted throughout the work.

Manufactured and Erected by

DORMAN, LONG & CO., LTD.

STEELMAKERS, CONSTRUCTIONAL ENGINEERS AND

· BRIEGK · BUILDERS:

MIDDLESBROUGH AND LONDON.

HONG KONG DAILY PRESS, SATURDAY, SEPTEMBER 5, 1931.

ENGINEERING AND

THE BRIDGES OF LONDON.

OLD PROBLEM, STILL UNSOLVED.

YEARS OF TALK END

THEY BEGAN,

WORLD SHIP BUILDING.

LLOYD'S REGISTER

RETURNS...

Tha quarterly shipbuilding re- tarns of Lloyd's Register show that. 101 vessels, of 855,903 tons, were under construction in the shipyards

BUILDING

CONDENSER DESIGN.

COURSE OF DEVELOPMENT

There was a time in the history of the condenser when all designs were much alike and ond was about

good as another. In those days no high performances were requir

of Great Britain and Ireland sted, for anything more than a very the end of last month, or 138,211 bons (22 vessels) less than at the ond of March, and 836,040 tons (210

moderate vacuum was wasted on the reciprocating engine. The tempera-

claimed. Experience with these the bottom of the condensor. There various designs brought out one im-it escapes, passing upward through portant fact that, other things na the tubo system until its condensa

ing equal, the best results were obtained when the entering steam came directly into contact with na great a tube surface as possible. High condensation rates could thus be secured, while the principle was favourable to small pressure drops

aarom the condensor.

Condensate Tampérat

The therma] oficiency of the whole

plaat demanded that no heat should traction of air separately from the be lost in the condensate The ex

condensate took away all reason for

tion is completed, instead of down- wards as in the orthodox manner. The condensate, as it drops from the tubes, falls through the ascend- ing, current of steam and finally through the steam space as the bot tom of the shell, before being with- drawn by the extraction pump. By this means it is raised to the full steam temperature before leaving

the condenser. The inversion of the

counterpart the inversion of the steam flow has as its neomary

Bow of cooling water in order that

The controversy over the improve ment and reconstruction of London's bridges seems likely as the Thames itself to go on for ever, unless something occurs to dam the vessels) less than in June of laat ture of the condensate was regarded cooling the latter, and enabled the the most effective heat tranference flood of argument, and disputation.: year. Tho-figuro is, in fact, lower with complota indifference. Indeed designer to aim. at the ideal of a

The.

condensate equal in temperature to

one of the leading makers claimed sorangan

may be obtained. Hence, countrary announcement recently that

than

at any quarter since Decem

to standard practice, the circulat the Charing Cross Bridge scheme ber, 1887, and it includes nearly would suco again be shelved by the 68,000 tons on which work has been it as a great improvement to cool the steam leaving the turbine. 19g water flows Arst through the withdrawal of Government support suspended. Of the total, 387,138 the condensate deliberately by the y

Under such conditions the eirculnt. upper tulies and then, through

lower ones. lower serves to remind the public that it tons (61 vessels) were for home incoming circulating water, thong water would carry away no. is now eight years since the whole for the British Dominions, and idos being to increase the density more than the absolute minimum of

owners, 23,210 tons (seven vessels)"}

81,954 tons (13 vessels) for Norway, while 11 vessels, of $3,431 tons, of the air to be handled by the air- were for unstated owners or for sale.

1. pump: The development of the

steam turbine put an end to these casy-going conditions. A prime

question, which, in relation to cer- tain bridges, had been revived at intervals since 1854, was thrown into the melting pot by the discovery Abroad the tonnage under oon- of a subsidence under Waterloo struction at the end of June-271 Bridge..

vessels, of 1,270,384 tons--was lose by over 38,000 tona tham at the end

heat-namely.

arily given, tent, hoat neccs-

the process of condensation. This idol has now been obtained by arranging for the

Another innovation is the extrac tion of the air from the highest point in the

special aire condensor shell. No air-cooling space; either with or without baffles, has to be provided, for the whole of the

and the coldest of them are travers

At that time a long dispute was of March. Six countries bad more mover had come into existen ondensate, immediately beforo its tubes do their part in air-cooling,

in progress concerning St. Paul's than 100,000 tons in head-the which could take advantage of the extraction, to be brought into in-

bridge and the possibility of re- France with 211,030 tons, Italy with highest vacuum practically obtaintimate association with the stehm, ed last by the air. The design

United States with 301,480 tons, 170,688 tons, Germany with 130,851"

placing Charing Cross bridge, but the possibility of disaster to the only bridge which separated them, at once gave rise to problems of moro urgent and most diversified nature, and in order to obtain ex country. About one-third of it arose a far greater interest in the pert recommendations, with the 987,810 tana), of which 8, of British Coadensor designers were there the consisted of oil-tankers (77 of thermal efficiency of steam plant.

of the day appointed the Royal yards, 11, of 85,100 tons, in Sweden, fore forced to a closer study of the Commission on Cross-River TransAll but 10 were motor-ships.

and B. of 32,000 tona," in Germany.

principles underlying their work and of the constructional features

tons, Sweden with 110,255 tons, and able, and, in fact, demanded much Holland with 106,299 tons: The total a vacuum for its most economical tonnage under construction in the world amounted to 1,828,987 tons, of operation. Simultaneously there which 30.4 per cent was in this

port.

This body met for the first time in June, 1928, and six months later presented the first constructive con tribution to the settlement of the problems in its entirety since po posals for a new road bridge were put forward nearly 70 years before.

Great Britain.

243,315

In Great Britain and Ireland only most appropriate for carrying these 23,350 tons. (25 vessels) were comprinciples into effect. menced during the quarter, com- Conventional practice, however, pared with a monthly average of retained, such influence that im over 184,000 tons during the six months ended March, 1930. The provement was comparatively slow, launches last quarter amounted to and looking back over the develop 170,000 tons (44 vessels). Abroad

commenced exceeded the launches

211,079 tons were commenced, and ment of the past 30 years one won 302,050 tons were launched. Among ders at the time taken to realize. the few countries in which the work the features now recognized" as were Italy, with two ships, of 58,300 tons, commenced and 11, of 18,884 tons, launched, and shouted States, with 15, of 88,950 tons, com

It thus regains any heat lost by contact with the cold tubes and may

ho said to

take a small part in the work of condensation.

even

would appear to embody in the sim plest manner all the principles on which the highest efficiency depends, and the results of prolonged tests have more than justified the com-

The principal remaining problem pleto departure from time-honour was concerned with the removal of practice. An incidental advan--

the air which comes over with the taga is the removal of all risk of

steam or otherwise finds its way into the condenser. The colder, and therefore the denser, the air could bo made the more readily could it”

he disposed of by the extraction ap paratus and tho lesa would be the amount of vapour withdrawn with it. Hence practice at one time tended to the provision of special

Seven New Bridges. Briefly, it was recommended that Waterloo Bridge should be recon structed; that the new St. Paul's Bridge project should be abandon ed; and that seven new bridges (menced and 20, of 39,180 tons, constant among the tubes: and of of tubes carrying circulating water

Motor Ships,

essential to good performance. An air-cooling spaces separated by early step was the introduction of baffles from the rest of the can- baffles, for the double purpose of denser and traversed by a number keeping the steam velocity fairly.

Inverted Flow

draining off the water of condensa in its coldcat state. For the first three-quarters oftion in stages. The intentions, how 1930 the tonnnge of motor-ships ever, were superior to the resuite, under construction in Great Britain for the design, among other faults, and Ireland exceeded that of steam involved a high resistance to the ships. In December, however,

should be built, including a new launched. double-deck bridge at Charing Cross, a new bridge from South- Bark Street to Holborn-viaduct, and five new bridges above Putney It was also proposed 'that severa? other bridges should be widened and improved.

ciently well obtained by spacing the latter more closely as the stom volume diminished, and infinite in genuity was displayed in dovising now tube arrangements, for each of which special advantages could be

The most radical change which has recently been made in condenser

a design in which the conventionul arrangements are completely invert- ed. The steam, before coming into contact with any cooling surface, is led by an internal duct of sheet motal directly to a large space nt

steamships took the lead, and in steam flow. It became obvious that practice is due to Messrs. CA March last their tonnage (305,352 the maintenance of the steam velo-Parsons & Co., who have developed tons) again exceeded that of the pity over the tubes could be suffi This was five years ago. To-day, anotor ships by 100,000 tons, and in Waterloo Bridge stands in a state June (330,805 tous) by 120,301 tons Abroad, the motor-ships under con- of apparently permanent under struction (667,304 tons) at the end repair," and a new bridge at Lam of last quarter exceeded the steam beth is practically completed. Be-ships by 47,805 tons.

Of the steamers building in the yond this, below Putney Bridge not world at the end of June four were a step has been taken either 10-between 8,000 ton 10,000 tons, and wards the fulfilment of the Com. seven between 10,000 and 15,000, mission's recommendations or the

tons, the motor-ships in these two categories numbering 20 and 14, solution of the cross-river traffic respectively. Of large vessels, bow. probleme, which are growing daily ever, there were 18 steamers, of be more complicated.

tween 15,000 und 20,000 tons; and seven exceeding 30,000 tons, but The three bridges on which the only four motor-ships in the former disputes of the ist few years have division and none in the latter. mainly centred are St. Paul's, The steam engines being built or Waterloo, and Charing Cross... being fitted on board' had an aggre

3

At present the first remains, and gate of about 1,162,000 h.p, includ- is likely to remain, in the same ing 60 sets of turbines of about state as that in which it stood 1,037,909 s.h.p. For oil engines the when the disputes began; "the figure was about 707,000 h.p. second still runs parallel with a temporary bridge which was opened in August, 1925; and the third, which was to have been re- constructed approximately 76 years ago, stands serenely as it did when it was first constructed, and will probably continue to do so for many years to come,

Phases of the I Dupate, Here, briefly, are the principal dates in the post-war phase of the disputen

Various schemes for the reconstruction of St. Paul's "and Charing Cross Bridges under con sideration.se

December, 1023-Berions sub sidence detected in Waterloo Bridge; temporary. preservation measures adopted

May. 1024 Royal Fine ATE Commission on the projected now. St. Paul's Bridge appointed,

July, 1924.-Royal Fine Art Commission reports.

August, 1925,--Temporary bridge, opened beside Waterloo, with stringent speed restrictions, a ***June, 1990-Royal Cammission

on Cross-River Trafo appointed.

December, 1026-Royal Com2 mission's repare mesta with gene eral approval.-----

October, 1928-Work begun on the new Lambeth Bridge.

1029-Committee of Engineers reports in favour of replacing bridge. A modification of this Hungerford foot-bridge by a rand

scheme agreed upon by the Southern Railway and the LC.C Bill framed on these lines for pre- tentation to Parliament.

July, 1930-Bill rejected by Par liament LCC Advisory Com mittes appointed.

March, 1931-Advisory Commit- tee reports in favour of road bridge at Charing Cross

June, 1931-LC.C. applies for power to procesd with this sahome, subject to. & grant from the Government

5 July, 1831,—Grant refused. Bir: Percy Simmons states that he has given instructions to those con cerned to be prepared to continuo with the original LO.C. scheme" for the widening of Waterloq Bridge into a six-way thorough- fare is the only alternative, m Thus the problem of London's bridges in further from solution tinn ever it has been in its waxed his- tory. Certain interested bodied. have-announced their intention_of

**** 1923,—Committed" of Engineers fighting to the last any resonatené..

appointed by the Government. tion scheme for Waterloo Bridge, (Continued at foot-of-next column.) Mandithan,

to the mixture of water and steam discharged at high velocity from the turbine exhaust.-The Times.

A LITTLE

care in setting up an advertisement. often doubles its selling power.

It is that little extra thought and care, which given to advertisement drawn up in the office of the Hong Kong Daily Press, which brings good resulta. -

'COLORCRETE

ANTI-GLARE

COLOURED

SNOWCRETE

WHITE-

FERROCRETE

RAPID HARDENING

PORTLAND CEMENT

SOLE AGENTS

STOCKS CARKTED

DODWELL & CO. LTD.

QUEEN'S-BUILDING: - HÙNG CONG

PHONE 280917