FR2527504A1 - MOBILE CONCRETE PLANT COMPRISING AN IMPROVED CEMENT EXTRACTION DEVICE - Google Patents

Abstract

1. A mobile concrete plant comprising a mixer in which an aggregate supply device, a water inlet, and a cement extraction device, comprising a silo (1) with a trough-shaped base, inclined along its longitudinal axis, and having a V-section, an extracting screw (4) placed in said trough, and a lifting screw, end, characterised in that the extracting screw (4) is a double-action screw, the lifting screw (6), inclined at an angle of 30 to 70 degrees relative to the horizontal, crosses the silo (1) close to the extracting screw (4), and the two screws communicate via a short-length neck (8), the thread of the helices of the extracting screw (4) reversing at the communicating neck (8).

Description

The present invention relates to the manufacture of concrete on construction sites,

  and more particularly a mobile power station

improved concrete.

  Conventional concrete plants generally comprise a cement extraction device consisting of an integrated silo, equipped with a system of extractor screws and elevating screws bringing the cement to a weighing device, for example a rocker, and then a mixer, which also results in an aggregate extraction device, sand and pebbles, by a mobile transporter completed by a hopper and a second weighing device, for example a weighing belt.

  The cement-integrated silo occupies an inclined position

  a slope of about 150 to limit its size,

  and usually includes two parallel udders that can

  read the cement all the way Through the bottom of each udder having the shape of a trough, is placed an extracting screw bringing back the cement to the back of the silo from where it is extracted by two elevating screws placed on each side Other extracting screws These two tubular elevating screws traverse the silo along its entire length and raise the cement up to a rocker from where it is poured.

in the mixer.

  This device makes it possible to produce a mobile concrete plant

  relatively small, maois has some disadvantages

  In fact, the slopes of the udders do not allow

  a steady flow of cement, and consequently the

  extractive screws are irregular and many "dead piles" are formed. In addition, the concentration of

  cement in the rear part of the silo and the lack of

  the two lifting screws cause a

  charge of these which causes an abnormal increase

  of intensity in the geared motors which disjunct fre-

  quently. There is also known an extraction device in a mobile power plant having an integrated silo, inclined from 30 to about 450, and two parallel udders along the entire length of the silo channeling the cement, each carrying a double-function screw; the double-function auger is extracting under the silo and lifting up to a cement scale However, this type of extraction proves difficult, and reduces the capacity of the silo, and it follows that its

  effectiveness is not satisfactory.

  The subject of the present invention is a mobile power station

  concrete of the above type, having an extractive

  single-screw extraction cement and a single lift screw. The invention more particularly relates to a mobile concrete plant whose construction is simpler and the

  more efficient operation than usual plants.

  The mobile concrete plant according to the present invention is of the type comprising a mixer to which end an aggregate feeding device, a cement extraction device and a water inlet; the cement extraction device comprises a trough-shaped trough bottomed along its longitudinal axis, of V-shaped section, a double-acting extraction screw placed in the bottom of the trough and a lifting screw passing through the silo nearby. of the screw

  extractor, and communicating with her.

  More particularly, the inclination of the extrac-

  cement silo, in working position

  is about 10 to 200 relative to the horizontal, and preferably about 150 The trough-shaped silo

  has a bottom section V-shaped, inclined

  each plane relative to the horizontal being

  between 40 and 600, and preferably equal to 500

  ron. According to a feature of the present invention, the trough

  of the extractor screw and the tube of the elevating screw

  by a short, downward-pointing neck, from the extractor screw to the elevator screw, located about 2/3 of the length of the silo from its lower end. This position may vary and may be modified by the technician depending on the inclination of the silo and the nature of the cement It is generally preferable that this communication neck is located in the upper part of the silo, near its middle. According to another characteristic of the present invention, the extraction screw located at the bottom of the trough is a double-acting screw: the turns located above the communication neck have a step to the left while the turns located below the neck have a step to the right, so that the rotational movement of the

  extractive screw has a driving effect of the cement containing

  naked in the silo, towards the communication neck with the elevator screw, that is to say that the cement in the upper part is brought down, while the cement in the lower part is pushed towards In addition, the operation of the screws is adjusted so that the flow of the extractor screw is

  greater than the flow of the elevator screw.

  The diameter of the extractor screw may be between 300 mm and 300 mm, the pitch of the turns being between 150 and mm in the upper part and between 170 and 30 mm in the upper part.

the bottom part.

  The diameter of the lifting screw can be between 200

  and 300 mm, the pitch of the turns being of the order of 150 to 250 mm.

  The inclination of the elevating screw is determined according to the operating conditions and the structure of the concrete plant. It can be between 30 and 700 with respect to the horizontal, and preferably between 50 and 50 mm.

and 600.

  The device according to the present invention provides a functioning of good efficiency, especially in the supply of the elevator screw, while reducing the material required for its construction, which reduces its manufacturing cost and improves its profitability. more,

  maintenance is facilitated, and the reliability of the

is improved.

  The entire silo, mixer, cement scale and other accessories such as the aggregate weighing belt, the water supply and weighing device, can be mounted on a movable machine that can be moved to the site. The features and advantages of the present invention

  will appear in more detail in the description below,

  relating to a preferential and non-restrictive mode of

  of the invention, with reference to the accompanying drawings which show:

  Figure 1: a schematic section of a cement silo

  carrying an extractor screw and a screw

according to the invention.

  Figure 2: a section along A-A of the device of the

gure 1.

  Figure 3: a detailed section of the extractor screws and

elevation of Figure 1.

  Figure 4: a section along B-B of the device of the

gure 3.

  As shown in Figure 1, the silo (1) is inclined at a slope of about 150 relative to the horizontal The bottom of this silo (1) has the shape of a V constituted by the two inclined planes (2 ) whose slope with respect to the horizontal is approximately 500 (cf fig 2) In the trough bottom (3) of the silo (1) is placed a double effect extracting screw (4), supported by the intermediate bearing (5) and driven by a motor (not shown) placed at the end of the axis at its upper part I 1 can be for example a motor of a

  power of the order of 15 hp causing the screw in a

  rotational speed of 65 rpm, 65 t / h, in the case of an extractor screw 250 mm in diameter with turns having a pitch of 170 mm to the left in the upper part of the silo , and a step of 200 mm to the right in the lower part. The silo (1) is traversed in its upper part by a lifting screw (6) placed in a tube (7) which communicates with the trough (3) of the extraction screw (4) by the neck (3) located approximately at 2/3 of the length of the silo from the lower end The screw (6) extracts the cement contained in the silo (1) and pours it into the cement scale (9) where it is then poured into a Kneader of the usual type (not shown) The lifting screw (6) is driven by an Ocv motor, for example, giving it a rotational speed of 167 rpm, corresponding to a flow rate of 60 t / h for a screw 250 mm in diameter having turns of which the

not is 200 mm.

  Figures 3 and 4 show in more detail the extracting screw (4) in its trough (3), and the lifting screw (6)

  as well as the neck (8) connecting between the two screws.

  The cement in the silo (1) is returned by the extractor screw (4) double effect to the neck (8) where it falls by gravity on the elevator screw (6) which goes back

to the rocker.

Claims (6)

R E V E N D I C A T IO N S   A mobile concrete mixing plant comprising a mixer to which an aggregate feeding device, a cement extraction device and a water inlet terminate, characterized in that the cement extraction device comprises a bottom-up silo. trough, inclined along its longitudinal axis, V-section, a double-acting extractor screw placed in the trough, and a screw elevator through the silo nearby   of the extractor screw and communicating with it.   Mobile concrete plant according to claim 1, characterized in that   characterized in that the longitudinal axis of the silo is inclined   at an angle of 10 to 200 from the horizontal.   3 Mobile concrete batching plant according to any one of the   preceding claims, characterized in that the planes forming the bottom of the silo section Y, are inclined 40   600 to the horizontal.   4 mobile concrete plant according to claim 1, characterized   characterized in that the extracting screw and the lifting screw communicate via a neck of short length located approximately 2/3 of the length of the silo from its lower end, mobile concrete plant according to claim 1, characterized in that that the extractor screw is a double screw   effect having in its upper part coils pre-   feeling a step to the left, and in its lower part,   turns with a step to the right.   Mobile batching plant according to claim 5, characterized   in that the pitch of the turns in the lower part   is larger than in the upper part.   Mobile batching plant according to Claim 1, characterized in that the flow rate of the extracting screw is   greater than the flow of the elevator screw.