Conveyors: fluid current – Intake to fluid current conveyor – Conveyor having plural intakes
Reexamination Certificate
2001-02-28
2002-07-16
Ellis, Christopher P. (Department: 3651)
Conveyors: fluid current
Intake to fluid current conveyor
Conveyor having plural intakes
C406S023000, C406S032000, C406S145000, C406S146000
Reexamination Certificate
active
06419425
ABSTRACT:
The present invention relates to an operator distributing a granular material, in particular sand, from a fixed workstation. In particular, it relates to filling the bunkers, commonly known as “sand boxes” that are provided on trains and trams. More precisely, the invention relates to apparatus for filling said sand boxes from a fixed workstation referred to as a “sand point”, while the boxes lie within a determined area surrounding said workstation.
BACKGROUND OF THE INVENTION
Apparatus of the sand point type for distributing granular material is known, in particular from document EP 0 561 679, said apparatus having a transfer vessel for containing the material and a portable distribution head which is connected via a flexible hose to the transfer vessel, which vessel is fed with compressed air under pressure.
Such apparatus is generally part of a distribution installation having a plurality of fixed workstations, said installation also including a storage silo which is connected to and fills a plurality of storage vessels, each storage vessel being itself connected to and feeding a plurality of sand point type apparatuses as described above. The storage vessels and the sand point apparatuses can be placed on the ground, can possibly be buried, or they can be situated on raised gangways or supports.
When one or more trains are situated in the area situated close to a sand point, an operator fills the various sand boxes that are to be found in said zone by moving the distribution head of the sand point from one sand box to another. Nevertheless, this operation is restricted by the capacity of the transfer vessel of the sand point. When the level of sand in the vessel reaches a determined low threshold, sand can no longer be distributed properly to the distribution head so it becomes essential to interrupt the operation for the time required to fill the transfer vessel with sand coming from a storage vessel. This difficulty is of little importance when filing sand boxes of small capacity. However, it becomes unacceptable in countries where sand boxes are of larger capacity or where the number of sand boxes accessible from a given sand point is also large.
Naturally, to mitigate such a difficulty, it would suffice to increase the capacity of the sand point transfer vessel. Nevertheless, such an increase gives rise to other difficulties, in particular it is difficult to obtain continuous transfer without the sand jolting in the transfer hose connecting the transfer vessel to the portable distribution head. The greater the sand capacity of the transfer vessel, the greater the difficulty in controlling the compressed air pressure and flow rate conditions so as to obtain transfer under acceptable conditions of safety for the operator. In addition, in the event of an accident, e.g. the vessel being empty of sand and under air pressure because the low level was not detected, the discharge of air under pressure from the vessel presents risks of injuring the operator by a phenomenon identical to that of compressed air expanding in a hose that is not properly maintained. The greater the volume of the vessel, the higher the risk.
OBJECTS AND SUMMARY OF THE INVENTION
The object the Applicant seeks to achieve is to mitigate those drawbacks.
This object is fully achieved by the apparatus of the invention. The invention provides apparatus for distributing granular material, in particular sand, and comprising in a manner known from document EP 0 561 679:
a) a portable distribution head;
b) a flexible hose for transferring the material to the portable head;
c) a main feed duct for feeding material from a storage vessel; and
d) a main suction duct associated with the flexible hose for sucking dust from the portable head.
In a manner characteristic of the invention, the apparatus also comprises:
e) a plurality n of transfer vessels, each vessel:
being fed with material via a secondary feed duct fitted with a valve;
receiving, filtering, and exhausting suction air coming from the portable head via a secondary suction duct fitted with a valve;
delivering the material via a secondary delivery duct fitted with a valve; and
also being fitted with two sensors for sensing the level of the material, a high sensor and a low sensor;
f) three sets of multiple connections, the first set connecting the n secondary feed ducts to the main feed duct, the second set connecting the n secondary suction ducts to the main suction duct, and the third set connecting the n secondary delivery ducts to the transfer hose; and
g) control means connected to
3
n
valves and to the
2
n
level sensors, said means being programmed to make it possible to obtain substantially continuous operation of the distribution head based on alternating operation of the n transfer vessels by a changeover effect whereby one vessel is emptying while at least one other vessel is filling.
The number n of transfer vessels is generally two, or possibly three.
With two transfer vessels, operation takes place completely continuously with filling of a transfer vessel being transparent to the operator, providing, in operation, the rate material is fed to the vessel being filled is not less than the rate at which material is being removed via the distribution head. Nevertheless, even if this condition is not complied with in full, a combination of two transfer vessels of smaller volume operating in alternation makes it possible to work with a volume of material which is always greater than twice the capacity of two of said vessels.
In practices when the material drops below the threshold corresponding to said level, it is the low level sensor of the vessel that is being emptied which serves to trigger changeover of the control means causing firstly the distribution head to be fed from the other vessel and secondly the emptied vessel to be refilled. The high level sensor causes the valve in the secondary feed pipe-of the corresponding vessel to be closed once the material has reached the determined high level. An apparatus with two transfer vessels each having a volume of about 200 liters has been found to be sufficient for filling the sand boxes of locomotives of the type developed in North America which have a capacity of more than 700 liters, with two sand boxes at the front and one sand box at the rear of the locomotive, each sand box generally needing to be filled with half its capacity on each operation.
To minimize the amount of space occupied on the platform, the n secondary feed ducts, the n secondary suction ducts, the n secondary delivery ducts, the three multiple connection assemblies, the
3
n
valves, and the control means are preferably placed in a housing structure extending between the n transfer vessels, said vessels preferably being in the form of vertical axis cylinders.
Advantageously, the housing structure comprises a central post terminated by a substantially horizontal arm which supports the hose, which is pivotally mounted, and which has its free end situated perceptibly beyond the transfer vessels.
Another difficulty lies in the length of certain locomotives which can be as much as 25 meters (m) long, thus making it necessary to increase the length of the hose connecting the transfer vessel to the distribution head.
Another difficulty lies in the fact that in certain locomotives, particularly in North America, the inlet orifice to the sand box is not disposed on the side adjacent to the platform at man height, but is high up, requiring filling to be performed vertically.
Another object the Applicant seeks to achieve is to mitigate the above-mentioned difficulties. This object is fully achieved by a variant embodiment of the invention in which the secondary delivery duct is connected to the corresponding transfer vessel at the top thereof, via a delivery tube which penetrates obliquely into the inside of the vessel and whose open end is situated near the bottom thereof.
The transfer vessel is optionally fitted with additional air feed means close to said end of the tube. Thus, the additional air which is fed towards the end of
De Cauwer Patrick
Fourcroy Jean-Pierre
Renaudin Yves
Dillon, Jr. Joe
Ellis Christopher P.
Neu Transf'air
Weingarten Schurgin, Gagnebin & Lebovici LLP
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