GB2175515A - Mineral breaker - Google Patents

Abstract

A mineral breaker has a breaker drum provided with picks 62 and rotatably mounted in a housing, the housing having a bore portion 20 for housing a portion of the breaker drum, said portion of the breaker drum including at least one helical rib 63 which has an outer periphery closely spaced from the internal wall of the bore. The helical rib serves to force broken mineral through an outlet located at one axial end of the bore and comprises an annular member 23 containing a plurality of apertures and provided with a pick 26. Conical surface 73 may be arranged for eccentric rotation to facilitate movement of material towards the outlet. <IMAGE>

Description

SPECIFICATION Mineral breaker The present invention relates to a mineral breaker particularly suitable for supplying broken material into a pressurised fluid conveying system.

According to one aspect of the present invention there is provided a mineral breaker having a breaker drum rotatably mounted in a housing, the housing having a bore portion for housing a portion of the breaker drum, said portion of the breaker drum including at least one helical rib which has an outer periphery closely spaced from the internal wall of the bore, the helical rib serving to force broken mineral through an outlet located at one axial end of said bore.

Reference is now made to the accompanying drawings in which: Figure 1 is a side view of a mineral breaker according to the present invention; Figure 2 is an axial section through the breaker shown in Figure 1; Figure 3 is a section along line Ill-Ill in Figure 1; and Figure 4 is an end view of an assembly which defines the material outlet of the breaker.

The breaker 10 includes a housing 12 which rotatably supports a breaker drum 14.

The housing 12 defines an inlet opening 15 into which dirt and mineral to be broken may be deposited onto one end portion 14a of the drum 14.

The housing also defines a bore portion 20 through which the drum 14 extends. The terminal end of the bore portion 20 opposite to the inlet opening 15 defines an outlet 22 for broken mineral.

As seen in Figures 2 and 4the outlet 22 is formed by an annular member 23 which contains a series of apertures 24 through which dirt and broken mineral is forced. Adjacent each aperture 24 there is located a pick 26 which serves to break down oversized mineral pieces to enable the broken down mineral to pass through apertures 24. The motive force for forcing mineral against picks 26 and through apertures 24 is derived from the breaker drum as will be described in greater detail later.

The dirt and broken mineral falls from the apertures 24 into a receiving chamber 30 and therefrom into a conduit 32 along which pressurised fluid flows for transporting the dirt and broken mineral away to a discharge location.

The size of the apertures 24 determines the maximum size of broken mineral pieces falling into the receiving chamber 30. Accordingly, the maximum size of broken mineral pieces may be changed by replacing the annular member 23 by a different one having apertures of a different size. To facilitate changing of annular members 23 the chamber 30 is constructed from two separable halves, viz. an upper half 34 and a lower half 36 which are bolted together at flanges 33.

The upper and lower halves have an annular groove 37 for accommodating the outer marginal edge portion 39 of the annular member 23 and also an annular shoulder 40 which co-operates with an annular shoulder 42 on an end plate 44 of the housing 12. The annular member 23 is split along a diarnetric line as seen in Figure 4, the upper half 23a having a larger diameter than the lower half 23b so as to define a pair of shoulders 23c. When assembled, the shoulder 23C co-operate with the chamber halves34, to prevent the annular member 23 from turning during use.

Once the chamber halves 34,36 have been separated the annular member halves can be removed and replaced.

The chamber halves 34,36 also possess annular shoulders 46 which co-operate with an annular shoulder 48 on an end plate 50 in order to secure the end plate 50 in position. The end plate 50 supports a bearing 52 which in turn supports one terminal end of the breaker drum support shaft 55.

The opposite end of the support shaft 55 is carried by a bearing 56 which is mounted in a support cap 57. The support cap 57 is received in a sleeve 58 which is preferably cast integrally with the lower housing portion 12a. The cap 57 includes a radially projecting flange 59 which co-operates with the sleeve 58 to absorb axial loadings applied onto the shaft 55 during use.

The drum 14 includes a first portion 60 which comprises a helical formation defined by a helical rib 61 on which is mounted a series of picks 62. As seen in Figure 2, the picks 62 are closely spaced and sweep close to the walls of the housing 12.

Accordingly, dirt deposited through opening 15 is acted upon by the helical formation and is caused to be moved axially along the drum toward the outlet 22.

Mineral pieces which are of a larger size than can be accommodated between the helix of the helical formation are acted upon and broken down by the picks 62. The broken mineral pieces are then moved by the helical formation towards the outlet 22 and into the bore portion 20 of the housing.

Within the bore portion 20, the construction of the helical formation is changed so as to be a helical rib 63 only. The outer periphery of the helical rib 63 is spaced closely to the internal wall of the bore portion 20.

The rib 63 serves to move dirt and mineral pieces toward the annular member 23 and in so doing compresses and compacts the dirt and mineral mixture against the annular member 23. Such an action has the effect of forcing dirt and small mineral pieces through the apertures 24 and forces oversized pieces of mineral onto the picks 26 to reduce the mineral to a size able to pass through apertures 24.

Since the dirt/mineral mixture is compacted in the region of the helical rib 63, an effective seal is provided to prevent pressurised fluid passing from the chamber 30 and along the bore portion 20 to exit through opening 15.

In the embodiment illustrated, the breaker drum 14 includes a first sleeve 70 and a second sleeve 71 both of which are keyed to the support shaft 55 and are both cast from a suitable metal. The ribs 61 and 63 are integrally cast with their respective sleeves 70,71.

Sleeve 71 is formed so as to have a conical outer surface 73 so that its outer diameter gradually increases toward the outlet 22. The maximum radius of the sleeve 71 approximates to the radial dimension of the radially inner edge of apertures 24.

In this way, material being fed to the annular member 23 does not encounter a sharp change in contour or a shoulder which could otherwise create a build up of material and ultimately a blockage.

The conical outer surface 73 may be eccentrically arranged relative to the axis of rotation in order to facilitate movement of material towards the outlet 22.

Similarly, the radial dimension of the radially outer edge of apertures 24 approximates to the radius of the bore portion 20.

Conveniently, the annular member halves are constructed from inner and outer marginal portions 38,39 with picks 26 secured therebetween by welding.

Claims (7)

1. A mineral breaker having a breaker drum rotatably mounted in a housing, the housing having a bore portion for housing a portion of the breaker drum, said portion of the breaker drum including at least one helical rib which has an outer periphery closely spaced from the internal wail of the bore, the helical rib serving to force broken mineral through an outlet located at one axial end of the bore.

2. A mineral breaker according to Claim 1, wherein the outlet is defined by an annular member having a series of circumferentially spaced apertures with picks located therebetween.

3. A mineral breaker according to Claim 2, wherein the helical rib is mounted on a sleeve having a maximum radius approximating to the radial dimension of the radially inner edge of said apertures.

4. A mineral breaker according to Claim 2 or 3, wherein the annular member is split along a diametric line.

5. A mineral breaker according to any preceding claim, wherein a receiving chamber is provided into which material is deposited from the outlet, the receiving chamber including a bearing support for rotatably supporting one end of said breaker drum.

6. A mineral breaker according to Claim 5 when dependent on Claims 2 to 4, wherein the receiving chamber is constructed so as to detachably support said annular member.

7. A mineral breaker substantially as described herein with reference to and as illustrated in any of the accompanying drawings.