WO2008061650A1 - Device for controlling sand quantities in rail vehicles - Google Patents

Abstract

The invention relates to a device for controlling sand quantities in rail vehicles using a piston controlled sand metering and locking device (2) in sand spreading systems for rail vehicles, wherein an injector (3) having an injector nozzle (3a) is connected to the sand metering and locking device (2). A bypass line (4) ends in the injector (3). Following the compressed air connection, the compressed air distribution is carried out on the injector (3) via an air pressure valve channel.

Description

 Equipment for controlling sand levels in rail vehicles

The invention relates to a device for controlling small amounts of sand according to the preamble of claim 1. In piston-controlled sand dosing and shut-off devices, the problem is that depending on the respective system pressure or Sandförderdruckvolumen set by the injector different suction stresses in the sand and conductive area of the device. In the system described, the sand-conveying compressed air volume is passed completely through the injector nozzle.

System applications that use only very small sand flow settings combined with a high sand flow rate require a large volume of compressed air. In this case, there is the problem that with a minimum adjustment of the sand quantity (small metering piston opening gap), the spreading sand is compressed in the opening gap and blockages may occur. Depending on the sand qualities or sand grains used (usually grain sizes of 0.6-2.5 mm), this effect is essentially influenced (the larger the grain size, the greater the effect).

This clogging effect can be avoided in the system described only by a corresponding to the respective sand quality (sand grain) adapted, larger metering piston opening gap.

However, an adaptation of the metering piston opening gap is inevitably associated with a larger and unwanted amount of sand.

EP 1 418 108 A1 discloses an air driven sand dispenser comprising a sand container, a compressed air source, a sand suction chamber connected to the sand container and a nozzle connected to the compressed air source, the nozzle having an air inlet, an exhaust channel and a sand suction port the sand suction space is connected directly or indirectly to the nozzle via the sand suction opening, and wherein the nozzle is provided with a sand pipe in the flow direction. is arranged, wherein in the sand line, an air supply opens, the air supply and the nozzle are connected to the same compressed air source and means are provided for adjusting the ratio of the compressed air source to the nozzle and the air supplied to the amount of compressed air. The air supply, together with the throttle valve and the Y-piece, forms an accurately adjustable bypass for the airway through the nozzle.

In DE 103 33 637 Al a Sandaustragungseinrichtung is described with varying power, which has a bypass line that can be opened or closed with a solenoid valve. This solenoid valve is controlled by the control device. The bypass line bypasses the suction nozzle arrangement and opens directly into the delivery line, so that this delivery line can be blown away by means of a compressed air flow blown through the bypass line.

The metering device for a sanding plant according to DE 29 11 075 A1 shows a tightly sealable sand reservoir. A first partial air flow flows through the container and serves for drying, a second partial air flow is used for sand discharge. Both air streams are combined just before the sanding pipe.

US 2006/060441 A1 discloses a sanding system for a road vehicle which has a bypass line for bypassing the sand container.

The object of the invention is to avoid the clogging effect described in the known systems.

This object is achieved by the measure according to the characterizing part of claim 1.

The purpose of the bypass line is to generate a controlled partial air flow from the compressed air distribution channel to the injector chamber based on a defined and controlled sandblasting function in order to ensure by a controlled vacuum reduction that when the sand flow is adjusted to a minimum sand flow setting a blockage is avoided. By the measure according to the invention, a piston-controlled sanding system has now been created, which is fully flexible adaptable to the different requirements of modern rail vehicles and the vehicle operator with sufficient security and thus can be classified as railway grade.

Further progress is achieved by the measure according to claim 2.

Further features of the invention will be explained in more detail with reference to the drawing, in which an embodiment of the system according to the invention is shown.

Show it:

1 shows a cross section through the system. and the

2 and 3 details of the system of FIG. 1.

In Fig. 1, 1 denotes the sand reservoir, from which the sand passes into the piston-controlled sand dosing and shut-off device 2, to which an injector 3 connects, in which a bypass line 4 opens. From the injector 3 leads a sand line 5 to the gap between the wheel and rail.

The bypass line 4 is connected via the connecting piece 4a with the injector nozzle 3a, into which also the compressed air distribution channel 6 opens (FIGS. 2 and 3).

Claims

- A patent claims: 1. A device for controlling small amounts of sand in the area of a piston-controlled sand dosing and shut-off device for sand vehicles for rail vehicles, wherein the Sandforder compressed air flow is divided in the injector and in the injector an additional bypass line is provided, characterized in that the compressed air distribution following the Compressed air connection at the injector (3) via the air pressure distribution channel. 2. Device according to claim 1, characterized in that the injector or the controlled bypass line (4) connects to the compressed air distribution channel.