In January 1882 in the book «Proceedings of the Institute of Mechanical Engineers,» published an article by Edward B. Ellington (1845 — 1914) «Hydraulic lifts for transportation of passengers and cargo.» The author was a partner in Hydraulic Engineering Co., founded in 1869 as an engineer Brian Johnson in Chester, United Kingdom. By the mid 70-ies of the XIX century, the company began to specialize in the production of hydraulic systems, and as a result of this activity from 1869 to 1882 received 11 patents.
Two of them relate directly to the hydraulic lift, «Hydraulic lifts» (patent № 4,269 from the October 20, 1880) and «balancing hydraulic lifts» (patent № 5,149 from December 9, 1880). The latter system was the main theme of the article mentioned Ellington, which also provides a brief overview of typical hydraulic systems in the UK, that allows to consider the article as a sort of introduction to the history of the elevators in England in the late XIX century.
Noting that «in the last 10-15 years,» in England have spread «lifts running from the mechanical energy,» Ellington wrote: «… except shipyards and cargo railway stations, installation of mechanical lifting devices in public buildings, warehouses, in hotels, even large ones, is still the exception rather than the rule. » However, he believes that in the future the need for them will increase as the value of land in the «big cities» and «a corresponding increase in the height of buildings.» Higher building — a greater number of stairs that leads to the need for «a mechanical lift of any kind,» providing «comfort and convenience» users. This familiar rationalization on the need for lifts is accompanied by an equally familiar safety concerns. An interesting characteristic of this Ellington security issues. He believes that, although most people believe that the elevators are not safe, they still feel that they have to use this new technology:
«Accidents in the elevators, especially actuated mechanically so frequent that many doubt their suitability for the associated risk. But in more cases, their use becomes necessary, and you have to take risks. «
The crucial point, of course, was the degree of risk, which should «minimized».
According to Ellington, the element of risk associated with lifts, directly depends on the type of lift, which he divides into two main categories: use «mechanical means» or the device, and set in motion manually, with the help of steam, air, gas, or electricity, and hydraulic lifts. On the hand lifts it says as «a traveling winch or manual hoists», which are commonly used in the manufacture or in the warehouse. Most systems base Ellington described as a device which uses a winding drum, the coil block (block assembly mounted on the console, leaving the outer side of the warehouse) and a chain or a rope with a hook load moving upwards and downwards. The winding drum is driven manually or by gates or by endless rope coming to the winding drum through the large pulley. The article shows the drawings Ellington vertical projection installation that uses two types of collars and endless rope. The drawings show a brake, coupled with a pulley, through which runs an endless rope and driven by a separate brake rope. Use of the terms «coil block» and «hoist» somewhat surprising, since they are no longer associated with the ships, not the buildings. Ellington from 1862 to 1865 was an apprentice in the company of John Penn & Sons, renowned manufacturer of marine engines and other ship equipment, which explains such terminology.
Ellington wrote that the simple «stand to add to the chain guide» lift «turns the device into the elevator.» Conversion hoist the elevator required and the availability of protective devices «favorite idea — inserted above or below the cage safety device, retaining the cage in place in the event of breakage of a chain or a rope.» With justifiable, perhaps cynicism Ellington says: «Every few months a new born guard, always the best of all ever developed, and ensures that it will withstand any most severe tests and inspections, only how it can be subjected to.» With respect to the general safety of motor or gear systems, he believes that «generally there is almost no difference in the mechanisms used … it’s just a question of what kind of force sets it in motion.» Concerns Ellington these systems show his comments on the latest versions of the existing driving force: «The use of electricity in the lifting device is in its cradle. However, judging from the attempt to use it as a driving force for such devices, it apparently has the same disadvantages as the other methods discussed. » The main defect — the presence of too many components, including: a rope or chain, gear, and a winding drum protective devices — all this is simply too many opportunities for breakage and potential accident.
Ellington believes that the solution to the security problems of the elevator should be sought in the use of hydraulic energy. However, although he believes hydraulic elevators safer than other systems, in his opinion, all these lifts provide the same level of security. Ellington hydraulic lifts divides into two basic types: those based on the design of William Armstrong hydraulic cranes and hydraulic systems of direct action. He showed three types of lifts such as Armstrong (he calls them «hydraulic hoist»). In the first use of engines with a horizontal pusher, as well as fixed and moving pulleys and accelerating the cage with a counterweight (it is interesting that the counterweight joined the chain leading from the hydraulic motor, instead of hanging separately, going from cabin). The second scheme engine provided with a vertical reflux pusher, and the third hydraulic circuit system used with the vertical chain, which is driven by a smaller winding drum coupled to the winding drum, displacing the cage. In the drawings Ellington for each system is given a general view and a detailed view of the device node, e.g., the compound of the rope with the vent valve mechanism of the engine with horizontal pusher. Hydraulic elevators direct action relating to the second type by Ellington, also divided into three categories: systems without counterweight, and the counterweight system with balanced hydraulic system.
A more preferred or «more safe» design — «direct-acting hydraulic cylinder, without counterweight.» Illustrating this system, Ellington shows a semicircular cabin with upholstered benches and a control system with a vent rope moving in the stairwell. However, while Ellington claims that this system of «absolute safety issue seems resolved» very simple design is a functional problem: at a given pressure and raises the load there is a limit to the height of the elevator lift. The pressure in plunger cylinder decreases as the lift of the plunger. During the ascent at a predetermined pressure water plunger will go some distance and then stop; when running under a given load, he will go down for some distance and then stop.
The solution to this problem was the use of a counterweight to balance the weight of the cylinder plunger: standard practice to add counterweights and chains slung over at the top of the pulleys. Chain has a weight sufficient to balance the displacement of the plunger. When the car is at the bottom, a plunger and a counterweight to stand balanced weight minus the weight of the chains, and when the car is at the top of the plunger and stand balanced counterweight weight plus the weight of the chains.
However, in this system, the newly emerging «moderate probability of an accident» due to the impact of the counterweight on the plunger cylinder when lifting: hydraulic elevators direct chain and counterweight loads are changing the nature of the load on the cylinder plunger. A significant portion of the plunger from the top, instead of supporting stand as a pillar hanging from it: part of the plunger is extended, the other part is always compressed, and a neutral site constantly changes position in accordance with the pressure on the plunger. If the plunger breaks on a neutral site or not sustain the connection between the plug and the cage, the cage will sharply pull up the counterweight. This accident occurred in Paris at the Grand Hotel in 1878, killing three people. According to Ellington, the problem can be solved by increasing the water pressure on the plunger, so that did not require a counterweight for efficient and safe operation.
At this point, the article Ellington starts to go in an unexpected direction: instead of describing his own design, to solve this problem, it describes a system designed by Ferdinand and Emile Hortebize Tommasi. Their team worked in the French company’s Ascenseur Heurtebise, in Paris, and the system is patented in France, Belgium, Italy, Germany and Spain in 1878 and in the US — in 1881 («Hydraulic lifts» Patent № 247,133). These elevator («L’ascenseur a compensateur») interconnected by a pair of vertical equalizing cylinders that balance the weight of the cage and the plunger to ensure that the piston remains in a compressed state. According to Ellington, although this system is «satisfactory from the point of view of safety, lt; … gt; weight and size of the cylinders, as well as moving parts is so large that the use of such a system is impractical in large quantities. » In view of such criticism lift Tommasi and Hortebize and coupled with the fact that it is the only foreign construction, considered Ellington (for example, no mention of the well-known vertical hydraulic elevator company Otis), is somewhat surprising that this particular structure, he analyzed and illustrated in his article.
However, the description of the design and Tommasi Hortebize may have been necessary because the basic method of operation is similar to the elevator Ellington (Ellington patented his elevator in France in 1881 — Patent № 142,135). Perhaps that’s why he said that in his elevator eliminated the problems inherent in the elevator and Hortebize Tommasi and his passenger elevator meets «all requirements for perfect safety, speed and efficiency.» He described the most important performance of its lift as follows:
1. As the driving force is water or under high or low pressure.
2. The plunger cylinder is permanently compressed and directly supports the load.
3. Net weight of the plunger and stand fully or partially balanced by a hydraulic pressure.
4. The displacement of the plunger cylinder is minimized and balanced without any special mechanism.
5. The weight of the elevator moving parts reduced to a minimum.
6. No audio items mechanism located above the stand.
7. There is not a single part of the mechanism, which oslabnuv, could, in the framework of a rational assessment, cause an accident to ascend or descend in the elevator passengers. Ellington illustrated two versions of his schemes elevator system with high-pressure and low-pressure circuits, each of which used his balancing cylinder, which «automatically compensates for» offset «cylinder plunger lift.» After describing his coming to the elevator Ellington apparently inevitable conclusion: «For practical purposes, the only really reliable elevators are those that run from the hydraulic pressure of direct action without the aid of any compensating circuits or balances.» In other words — it lifts its own design. It remains, however, one last question to be decided «as a preferable hydraulic energy from the point of view of economy.» After a brief discussion of this topic Ellington makes a second, obviously, is as inevitable conclusion:
«Consequently, while it is impossible to show that the use of hydraulic pressure to the plunger of direct action leads to more friction than a conventional system with a mechanism for performing the same work, hydraulic power remains the most economical and safest for the elevators of direct action.»
The article ends with the recognition that the author «has left without consideration many types of hydraulic elevators. He paid attention almost exclusively to a special class of elevators, which, in his opinion, have a number of characteristics of interest and limit the exception of one or two cases, the description of systems built under his leadership the company Hydraulic Engineering Co. of Chester. «
In the second part of this article will address some of the different «hydraulic lifts, left without attention,» Ellington. Among them are «patented water balanced lift» of R. Waygood & Co., which, according to the description, «ensure absolute security and distribution using the circuit.»