This invention relates generally to a screening apparatus, widely used in removing or separating dust, dirt, silt and fines from aggregate materials like sand and particularly, to an improved screening apparatus capable of sliding or retracting into a foldable configuration for easy transport.

Background to the Invention

Typically, there are a wide range of vibrating screens available, including an inclined, a horizontal or a multi-sloped screen which can be fitted with a wide range of screen media to suit varying needs of separation. The frequency of vibration in a vibrating screen is controlled by an electromagnetic vibrator connected to the screening surface. The high frequency vibrating screens usually operate at an inclined angle and require pre-treated feed to prevent the apertures of the screen from getting blocked.

Screening apparatus comprising a vibrating screen is generally employed to dewater sand and size the aggregates. The robust screen frame is typically manufactured in either a welded or a bolted design. The angle of vibratory agitation is optimized to reduce moisture of materials to minimum values. In order to dewater a material effectively, the slurry is fed on to a steep, upward inclined screen surface at the feed end and subject to counter-rotating vibratory motors aligned at an angle to the screen surface such that the abrupt reversal of motion detaches water from the material, and the water droplets pass through the screen media. The solids are then conveyed up the screen by linear motion.

This application derives priority from the United Kingdom patent application number 2103537.3, entitled “Mobile Wash Plant” and filed on 15 ^th March 2021 in the name of Tyrone International Limited. The said priority application relates to a fully functional, tracked, mobile wash plant or apparatus specifically designed to alleviate the drawbacks of static wash plants. The tracked mobile wash plant thus includes various components like log washer, vibrating screens, sand plant, conveyors, cyclone towers and sump tank etc. on a single mobile chassis. Such an arrangement helps to achieve full mobility of the set-up, has much quicker speed of installation and the ability to move and transport the plant easily. It is also more economical to install and operate than conventional static plants and does not require prior planning permission.

As also indicated in the specification of the earliest priority application, the various components comprising the tracked mobile wash plant can be aggregated to form the mobile wash plant unit as a whole as well as can be segregated from one another and exist as individual units, while still retaining the novel and inventive aspect within each component along with the associated benefits of the core invention.

Accordingly, the present invention provides a component of the tracked mobile wash plant, i.e., an improved screening apparatus comprising vibrating screens capable of folding or retracting to facilitate easy transport both as an independent unit and as a part of a wash plant. Without compromising with the scope, the screening apparatus can be fitted on a static wash plant as well, in addition to a mobile wash plant.

Summary of the Invention

The present invention provides an improved screening apparatus including a vibrating screen, suitable for use as an independent unit or as a part of either a static or a mobile wash plant for screening of granulated material like sand etc. into multiple grades according to particle size. Such apparatus is meant for separating feeds containing solid or crushed ores in both perfectly wetted and dried forms. The apparatus is characterized by folding or retracting from a raised working position to a levelled or retracted or folded non-working position by the folding or retracting of its vibrating screen, so as to facilitate easy transport of the set-up as a whole or the screening apparatus as an independent detached unit, from one place to another when not working.

Accordingly, from a first aspect, the invention is a screening apparatus comprising: a screen support frame, said frame including a plurality of stabilizing jack legs; a vibrating screen configured to slidably engage with the screen support frame, wherein the vibrating screen comprises an inlet for accepting material feed and a screen media for separating the material feed; and means for raising and lowering said vibrating screen relative to the screen support frame.

The screening apparatus is so constructed and assembled that it can be fitted on either a static or a mobile wash plant, e.g., to the chassis of a mobile wash plant.

Advantageously, the vibrating screen of the apparatus can be folded down into a transport position, thus alleviating the requirement of a crane for transportation purpose.

In a preferred embodiment, the screen support frame is provided with one or more guide channels for facilitating the sliding, lowering or folding of the vibrating screen.

Preferably one or more safety pins are located on the screen support frame for securing the vibrating screen in a lowered configuration.

The apparatus preferably comprises at least one lift unit which moves the vibrating screen from a transport position upwards to a working position and from the working position downwards to the transport position, preferably wherein said lift unit is a powered lift unit.

The or each lift unit may independently comprise a hydraulic lift unit. However, this is not to be considered limiting and other means of effecting movement such as an electric actuator, mechanical jack, etc. may be used in addition to or instead of a hydraulic lift unit. The hydraulic lift units may comprise hydraulic control banks having levers that operate hydraulic cylinders in connection with components of the apparatus so as to fold and unfold or push and retract the vibrating screen of the apparatus.

In a particularly preferred embodiment, the means for raising and lowering or folding of the vibrating screen comprises multiple hydraulic control banks including multiple hydraulic rams connected to the screen support frame.

Preferably, there are two hydraulic control banks and four hydraulic rams located around the screen support frame for raising and lowering or folding the vibrating screen.

In a preferred embodiment, there may be a plurality, e.g., three, vibrating screens in the screening apparatus. In another preferred embodiment, the need for three vibrating screens may be reduced to two vibrating screens, thereby proportionately reducing the height of the apparatus or the wash plant.

The design of this apparatus can be applied to various sized screens with single or multiple decks using a range of screen media with multiple apertures. The angle can be adjustable to suit the material being processed.

Preferably, there are four stabilizing jack legs forming a part of the screen support frame for holding and supporting the vibrating screen and the screen media. However, this is not to be considered limiting and more or fewer jack legs may be present on the apparatus.

In a preferred embodiment, the screen support frame is an outer screen support frame and the vibrating screen is mounted on an inner frame configured to slidably engage with the outer screen support frame, preferably wherein guide channels run diagonally along the inside of the outer screen support frame on either side for facilitating the sliding of inner screen support frame and thereto mounted vibrating screen.

Preferably, there are four guide channels at inclined angles with respect to the vibrating screen which run along the screen support frame so as to facilitate the sliding or folding of the apparatus. However, this is not to be considered limiting and more or fewer guide channels may be present on the apparatus.

Preferably, there are a plurality, e.g., four, safety pins located at multiple, e.g., four, locations on the screen support frame for securing the apparatus either in a raised or a folded configuration. However, this is not to be considered limiting and more or fewer safety pins may be present on the apparatus.

In another aspect of the invention, a method for transitioning the improved screening apparatus from a raised working position to a retracted, folded or levelled non-working or transport position is provided whereby the vibrating screen lowers or retracts or folds over the screen support frame, said method comprising lowering or pulling down the vibrating screen over the screen support frame, preferably along guide channels, particularly preferably using hydraulic rams. In a preferred embodiment, the method for transitioning the improved screening apparatus from a raised working position to a retracted, folded or levelled non-working or transport position comprises the following steps:

(a)removing safety pins from the screen support frame, followed by activating lift units located around the screen support frame;

(b) lowering the vibrating screen, preferably along guide channels, using the lift units;

(c) following the lowering of the vibrating screen, securing the safety pins at alternate locations on the screen support frame such that screening apparatus becomes ready for transport. In a particularly preferred embodiment, the method for transitioning the improved screening apparatus from a raised working position to a retracted, folded or levelled non-working or transport position comprising the following steps:

(a)removing the first two safety pins from the first two locations on the screen support frame, followed by activating the two hydraulic control banks and the four hydraulic rams located around the screen support frame;

(b) lowering the vibrating screen along the guide channels using the activated hydraulic control banks and the hydraulic rams;

(c) following the lowering of the vibrating screen, securing the other two safety pins at the other two respective locations on the screen support frame such that the screening apparatus becomes ready for transport.

The scope of the present invention is not limited to just the preferred embodiments but includes all the plausible variants concerning the assembly and operating mechanism of different parts of the screening apparatus.

Brief Description of Drawings Certain preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective isometric view of a preferred screening apparatus according to the invention in a working position and mounted to the chassis of a mobile wash plant;

Figure 2 is a perspective isometric view of the screening apparatus of Figure 1 with an outer portion of the screen support removed to expose internal workings;

Figure 3 is a perspective isometric view of the screening apparatus of Figure 1 in a transport position; and

Figure 4 is a perspective isometric view of the screening apparatus of Figure 3 with an outer portion of the screen support removed to expose internal workings.

Detailed Description

The invention will hereafter be more particularly described with reference to the accompanying drawings, which show an improved screening apparatus by way of example only and where like reference numeral represent like parts and assemblies throughout the several views.

Referring to the drawings, Figures 1 to 3 show a preferred screening apparatus according to one embodiment of the invention. The screening apparatus is shown mounted at one end to the chassis of a mobile wash plant and comprises a vibrating screen 1 with a screen media for separating material feed; an inner screen support frame 6 for holding and supporting the vibrating screen 1 and the screen media and an outer screen support frame including four stabilizing jack legs.

Inner frame 6 is configured to slidably engage with the outer screen support frame. There are two hydraulic control banks 7 including four hydraulic rams 4 for raising and lowering vibrating screen 1 and support frame 6 with respect to the outer frame. Four guide channels 5 run diagonally along the inside of outer screen support frame on either side for facilitating the sliding of inner screen support frame 6 and thereto mounted vibrating screen 1 . In the embodiment shown in the drawings, there are four safety pins 8, wherein two are located at location 2 and the other two at location 3 on the screen support frames for securing the vibrating screen 1 in raised and folded configurations, respectively.

The improved screening apparatus is capable of being retracted from raised working position to a horizontally levelled or retracted or folded transport position by lowering or retracting or folding of the vibrating screen over the screen support frame. A method resulting in such a transition comprises the following steps:

(a) removing the first two safety pins 8 from the first two locations 2 on the screen support frames, followed by activating the two hydraulic control banks 7 and the four hydraulic rams 4; (b) lowering vibrating screen 1 along guide channels 5 using the activated hydraulic control banks 7 and the hydraulic rams 4;

(c) following the lowering of the vibrating screen 1 , securing the other two safety pins 8 at the other two respective locations 3 on the screen support frames such that the vibrating screen 1 is secured in a folded or retracted configuration and the screening apparatus becomes ready for transport.

It is to be understood that the invention is not limited to the specific details described herein, which are given by way of examples only and various modifications and alterations are possible without departing from the scope of the invention as defined in the appended claims.