1931-09-26 — 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 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 Clinker is ground down with a small percentage of gypsum to regulate the setting time, and Green Island Portland Cement is thus › produced.

care.

الرحیم

Although sounding so simple, in reality the process is an intricate combination of mechanical, physical and chemical operations, needing great ekill and

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.

DAMP

Tine juddle Damp Houses

PUDLO

MESAZHAR BRAND

CEMENT WATERPROOFER

TEMPORARY REMEDIES

for dampness are never cheap. In a few years, they cost more than a really permanent and entirel satisfactory treatment with Portland Cement and +PUDLO? x and Waterproofer.

A booklet, in English or Chinese, describing the uses of 4 PUDLO! will be gladly sent on request by the Sole Agents for HONG KONG and SOUTH CHINA:T

DODWELL & CO., LTD. ||

CANTONA HONG KONG. FOOCHOW.

HONG KONG DAILY PRESS SATURDAY, SEPTEMBER 26, 1931.

ENGINEERING AND

AND BUILDING

APPLICATIONS OF COMPRESSED AIR FOR PUMPING.

SAVING ENERGY BY ABSENCE OF FRICTION, LOSSES.

THE AIR LIFT. AND THE DISPLACEMENT

PUMP

Of the several principles and numerous appliances used in the pumping of water and other quids thom involving the use of compressed air have claim to tention, by reason of a number of inherent advantages. There are oxamples of pumping in which the ase of the more usual types of turbine and reciprocating fumps are inadmissible, and whore the application of power through the medium of compressed air per

of ordinary reciprocating or rotary pampa Examples of this system -

TRAIN CONTROL.

HOW THE AUTOMATIC SYSTEM WORKS.

The Great Western Railway Com

Bristol and the shorter route

WHAT THE NAVY NEEDS.

(Continued from Papa y

Bearch System Impracticable. *The arguments explaining our. dre in operation, in which bores,pany has now equipped its main

line between London and Plymouth, requirements in cruisors dwelt on from, which water, originally-ralas su from a moderate dooth by both by the old route through the great dificulty in stopping ciprocating pumps censed to run- tion, had to be taken down to an through Westbury, with the auto raiders on oxit front, and return- amatio system of control. The idoning to their baso ports stressed increased depth, this later section. being deals with by roeans of com- of automatically pulling up a train she great length of the lines of in the event of its passing a signal pressed air,

communications and the wide areas. at "'danger.” is very old, but, un

Displacement Pumps

til continuous brakes became uni- over which our trade was scatter The displacement pump system,versal in the nineties, that could ed; showed the futility of attempt- only be done by the forcible closing ing to patrol 60,000 miles of trade of the regulator to that stop thero

then roalised by the use of two or more cylinders successively using to which brief reference has a the steam at reduced pressures. The ready been made, merits some at method is equally applicable in the tention. The principle can readi case of compressed air, there at ly be visualised. Two tanks are ing a marked increase in efficioither submerged in the liquid to anay by the use of the aft from be raised, as, for examples in the

sof the high pressure cylinder in a case of water, or placed in such second-cylinder of increased lume a position that they may be filled and utilising the air as it emerges from the low level tank by gravita from the high presure plunder.tion. Into one of them suitably This is an application which had compressed air is admitted, dis been fargely used. V

charging and elevating the water

were reasonable objections. The routes, to say nothing of the wide provision of continuous brakes on areas, with only one cruiser to traius changed the situation as 2,000 miles. In short, it confirmed automatic control applied the the war experience, that the search brake. Locomotive engineers thon protested that that would take the system is inpracticable and can control of the train out of the give no sourity to trade, but it hands of the driver. Thus auto-mado no mention of the convoy matic train control made no pro principle which can do so. Does it gress..

forms the required service not only The third pri lyin content. At the end of this stroke Concurrently there was a demand not seem possible that the entirely

adequately but also very efficient ly, In fact, as a medium for pow er transmission the applications of air in a compressed form are in creasing.

off for mechanical. the air the air is automatically cut

and similarly applied to the se. cond tank, while the air from the first tank is discharged to waste admitting a further supply of water from the low level supply, Those operations are repeated. They involve the use of no more mov ing parts than the walves, the whole of which are automatically controlled.

compressed air: ia lift, which now finds extensive ap plication, as it meets a number of conditions which cannot possibly bo catered for by other types of In somewhat the same. manne pumps. To the attraction of sim steam may be, and is, applied, but plicity thera is to be added an effi. its use occasions undue thermal ciancy in operation with relative losses, especially in cases in whichly simple construction: which is it comes into contact with the cold liquids which are being raised. There are, in addition, the usual loses attached to the transport of the steam from the point of produc tion to that of application. Tho use of compressed air suffere no auch handicap, and it is not aur prising that its use should be in-, creasing. Naturally, large se ia" made of steam by the isolation of the steam unit from the material to be pumped, this usually being effected through the application of the steam-driven pump.

paved the way for its usd not only in many examples in which the ordinary types of pumps would be quite inadmisible, but also for dealing with relatively simple ma- terials like water, which is dis posed in ways not readily acces sible to the more usual types of pumps.

| A simple computation serves to indicate the maximum height to which the liquid can be raised, with due allowance for the fosses

14

as not past experience abown that, given suitable ships, properly used, the Navy can give scurity needed," if its action

insurance.

doubted that sooner or later the submarine will forms the adoption

fog-signalling. orroneous and unfortunate imprest Most of the schemes ware of whatsion was left the security cannot is known as the cab-signal type be given

be given to our son-borne trade? ie., indications in the cab of the locomotive. These, in turn, came to grief on more reasonable grounds. Practically all the ideas submitted failed to provide for an intimation when he signal was at

clear"; that was knowledge that supplemented by a driver wanted, not only that he spread the losses": might continue to run at speed but because, according to the rules, the absence of a signal, where a agnat Admiral Custance concludes hit should be given, had to be regard brilliant argument thus: "Upon fed as equivalent to à danger in VENET dication, Another weakness in what conception should our cruiser of pressure and that due to ffic-nearly all the schemes submitted building policy rest! Can it bo tion. With air at 60lb this max that, in the event of a failure in was that provision was not made. mum height is of the order of 160 the apparatus, the danger sign fest. At the end of the stroke ital should be exhibited. The principle of the air lift is is obvious that the contained air The Great Western Bystem generally well known. A pipe is is still under a pressure of the Some twenty-five years ago one immersed into a depth of the li column of water elevated. The of the engineers on the North-East quid, and into it is passed air un discharge of this air to atmosphere in allway and some of the soon as convoys are stürled, will

signalling and operating officers on der pressure. The large bubbles would be wasteful. By the return the Great Western, both parties not escorts be required for them? One of the greatest advantages thus formed interpose short cosystem it can be more effently noting independently of each other, The strength and composition of

brought out what proved to be per- attaching to the use of compress Junina of liquid, the combined utilised. Alternatively the air, feet cab-aighals. It is the develop our cruiser foros will, therefore, ed air, however, in the total ab weight of the mixed column be still compressed at the end of its ment of the Great Western aigual, depend largely upon the demande first effort, can be used in a fur- to which, automatic train control of the convoy service. These de sence of maving parts and lue, abing much less than that of a sim

was subsequently added, that has sence, therefore, of the friction lar column of liquid alone. The ther tank raising the liquid now been put into operation bemands will call for numbers, and usually attaching to the rubbing uid mixture in the a pipe thus through an added but smaller tween London and Plymouth and fighting, power rather than for ex-

height, thereby increasing the total which will be equipped over the cessivo, spoed. surfaces. This is a saving of an

rians to a height commensurato lift of the water.

grentor part of the G.W.R. system argy which is by no means incon with the degree of air entrapped,

by the end of this year. Moreover,

siderable..

and both liquid, and air are dis

departmental committes who con sidered this question and reported charged from the top of the pipe designed of suitable length.

The AI TAN.

The advantages of air over steam in mine work are at least three fold. First, there are not the To this must also be added the

thermal losses inherent in the advantage that air is a perfectly

transmission of steam. Secondly, there is no problem of the dispos inert mterial in contnet with the While generally it might be al of the exhaust air an with the usual types of liquids requiring thought that the system would be case of steam; rather is there the pumping, and the absence of rub.amenable to fairly simpla design advantage that this discharge may be made to play some important ring surfaces considerably simpli- from the known properties of these part in the efficient and very he fire the problem of handling li-hydrostatic columns, experiencecessary ventilation of the teine quids of a viscous and also those goes to show that this is not re- of a corrosive character, assue liquids, including especially the aeide, can be dealt with in vessels constructed of practically non- corrodible materials, in which there is no rabbing action.

adily realised, and that the prac tical experienes of the problem carries considerable weight in. the design of a new installation

Modem Types..

This principle has of inte found increasing application in pumps of the non-immersion typ for

The system is by no means now. p There is evidenes of its use

to wards the close of the eighteenth Method of Application, i

century, while in the middle of There are several methods of ap- the last century it was opphed at plying the power of compressid air rast on the small send to the rais for pumping purpose. These dit-ing of the newly discovered petro for considerably in their principleum in America. It was, how

lés.

"Continued on, Page 3.).

of the convoy system in any futuro war as it did in the last one? Aa

an

Speed Relatively Unimportant.

But cruisers have many other

to the Minister of Transport last duties to perform besides convoy November said:-

We consider that the GW work. They represent a compro- ramp system is, ao far, the only mis fully developed method of provide and will be required in great ing the daul warning and variety. The solution of the com

clear effect at distant signals; plex problem can only be left to which can be recommended as meet- ing railway requirements in Great the instinct and judgment of officers Britain. We are also satiated, from of wide experience, whose aim will more than twenty years' experience | be to attain sceurity for our varied. gained on the Great Western Rail-interests by battle or the threat of way, that this type of ramp con tact. control can be properly main battle at the smallest cost." tained, and is sufficiently reliable, even under snow or ice conditions, for general adoption,

No apology in needed, unless perhaps to Admiral Custance, for In passing it may be observed thus reproducing a few of his para that the term warning "used graphs from an argument of such above is now employed to designate

In one type of apps the over, as the result of the investisions did not warrant the Ministry at "danger"; for a distant the Admiral Custance's shadow Đã đỡng”,

This type

being discarded and methods using indiction became and remain more popular. As no action had the "on" indication of a distant weight. His reputation as a Naval been taken in this country on the signal. A distant signal repeats strategist extends far beyond the 1930 Committee's report mainly the indication given by the stop shores of his country, whereas my because Sir John Pringle, the then signals at the signal-box a driver Chief Inserting Officer of Rail is approaching, and he has nonexistent. I think I shall be par- own is amall, if not definitely non- way, said in each of his annual pull up at it. It, therefore, is in- reports that the number of colli- correct to speak of a distant being doned, therefore, for crouching in of Transport calling upon the com- | two indications »are - “ warning compressed air functions the gations of Dr. Poble in 1888 that panies to inour the honvy financial and clear. An Arab in the shadow of a rock perfectly harmless clastic proton the system derived the impetus éxpenditure necessary it was de- The Great Western ramp system in a parched and weary land, Ad

cided in November, 1927, to recon-is exceedingly simple. At the dis in addition to storing the energy which led to its present extensive sider the question having regard tant signal there is, in the space miral Custante's argument, if it which is directly applied to the use

to the developments that have taken between the two rails of the track is valid, confirms the following surface of the liquid to be trans. The system has the advantage committee were not impressed by steel bar of inverted shape. place since that date. The second to which the distant is applicable,

outstanding characteristics se de ferred from on point to another that it is applicable to waters these developments" and. As iftain long. On the locomotive irable in our future ships, and

usually known to the

carrying considerable quantifies of shown above, advised the Great is a contact shoe no situated as to because these characteristics will dieptement pump, and sinds

qus of Western ramp method. to be in alignment with the ramp: foris, the subject of further discus

As yet, no company has made a The ramp is electrically connected large and efficient application in Mercover, as the air bubbles rise move towards imitating the exam to the lever in the signal box that sion in the coming months no ex- the pumping of acids and other they further expand with reduced ple of the Great Western. The works the distant signal, and our cuse is offered for summarising liquids of un' unusual type tu the second type of application the at atmospheric pressure. In the ern is using money advanced under is normal-e the signal in the Battleships should be smaller compressed air als kopt separate elevation of hot liquids this ex- the Government development warning position the ramp is our pulsors ahould be of more from the liquid being pumped by pansion is still more marked. The

scheme 2:15 maddend. Should the current fail the the interposition of a mechanical intimate contact of the air and appliance which takes the form of liquid may in some cases consti- a piston pump operated by tid tute a disadvantage, while in occasionally that record is beamirch- because the distant is at warp pleta convoy system; speed is re ed by some accident that automaticing, the brake valve is opened and tatively unimportant and should be compressed air in place of steam others it may be regarded as a train control, would have prevent a siren sounded it, however, the moderated in the interests of fighti This type of application is spivi distinct asset to the operation. The ed. The most horrible railway acramp is electrically, joined to thei ceable in cases in which it is not limitations imposed upon the procident in this country that lever because the distant is ating characteristics,

Charfield" in October 1928 – Would "elear" the current passes from Though r Admiral Custance has possible to lead the air right up cess are the facts that the au lift not have happened bad it been in the ramp through the contact shoe not entered the fuel controversy, by to the point where, tlm pumping is connor empty & tank-thura, munt; use, nor the biggest wreckage of and restrains; tas brake valva from to be effected.

be a considerable depth of immer Rollowing January, Coming to Is.rung The shoe drops; when it against excessive speed in men-of passenger traint Ashehurch, the being opened. In that event a bell clear and forceful arguments sonnor part the water elevated be quite recent days there in Leighton has passed off the Amway he is clearing the way, per

ramp discharged into a length of pipe.¡ Buzzard, on March 22. While this The Case for Automatic Control. Its extensive uss is, however, some is the main advantage of train on Mention was made above).

trol there are other of minglepartmental committee. That was. indication Corrits/applicability. but important character. Drivers

pressure, ultimately discharging calation probably no rent flows to the ramp when the

counts for that. The Great West lever is pulled over; when the lever them thus-

The record of British railways ramp is also dead. As the contact then, one type and their numbers for safety in travel is one of which shoe renches the ramp, it is gradual fixed mainly by the needs of a com they havo reason to be proud. But ly raised, and, if the ramp is dead

morathan/anyone;:force

The principle is applied in the case of steam, 1nt with a of disadvantages attendan upon. the type of appliñnog rather than the nature of the medium. In the In some cases, moreover, may in forsy weather and so osa run upstion. The earlier one was ap- of any

have the signala repeated in the cab the second body to investigate this to British xm the pressure mast bure pussitletus effect the faming with greater confidenskog pointed in Cletober 1930, and

during the whole of water from the lowest depths by sigualmen are lase necessary fur ported in, April 1822, stroke, and the admeans of the air lift continuing ther the risks run, saateshmended the ramp system. In the

hurch; from anduon.fogedoene uited States lie, támp method ive werking are the process of elevation by aneans, arise.

(Continued):

Case of maintained length; of

vantages.

atom ufy British coul tips without the need

subsidy for off ex