Gas separation: processes – Liquid contacting – And filtration of gas
Reexamination Certificate
1999-10-28
2001-11-06
Smith, Duane S. (Department: 1724)
Gas separation: processes
Liquid contacting
And filtration of gas
C055S385500, C095S215000, C095S216000, C095S225000, C095S228000, C096S356000, C096S358000, C096S361000
Reexamination Certificate
active
06312504
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a dust separator for use with dust-generating machines and/or plant for use in underground mining and tunnel construction, comprising a drive acting upon a fan impeller and disposed at the inlet side of the washer housing, inlet-side water nozzles and the separating elements for the dust-containing water, which are disposed at the outlet side, as well as a water tank with a valve-controlled water inlet and water outlet as well as a drain valve for the sludge.
In underground mining as well as in other branches of industry, dust separators are used to separate, in particular, respirable dust from the ambient air and deposit it in a safe place. So-called dry dust separators are known, in which the dust is conveyed through filter elements and so the dust is removed, wherein the filters equipped with a suitable filter cloth are dedusted at regular intervals in order to ensure a long service life of such filters. Apart from the fact that such dust separators are relatively large, it is a disadvantage that they have to be cleaned at specific intervals. For said purpose so-called rotary or wet washers are used, whereby the air containing dust is sucked, by means of a fan impeller operating in the air stream, into the washer housing before being loaded with finely distributed water and separated from said dust-containing water in downstream separating elements. The problem here is keeping the discharging clean air dry because, particularly in underground mining, moist air in turn poses additional problems.
SUMMARY OF THE INVENTION
The object of the invention is therefore to provide a powerful wet dust separator having a stable characteristic as well as a high dust separation and moisture separation efficiency.
The object is achieved according to the invention in that a gear unit is associated with the drive of the fan impeller acted upon by the mixture of air, dust and water, and that the separating elements comprise a demister, which is positioned so as to be inclined until approximately horizontal in the air stream.
Given a dust separator constructed in said manner, wet dust separation is advantageously effected without operation being hindered by the problems arising with previous wet dust separators. In particular, the gear unit ensures that the dust separator operates virtually independently of the dust and water content and/or independently of the quantity. The gear unit ensures uniform operation and hence a stable characteristic, which in turn also contributes towards uniformly clean air being discharged from the dust separator independently of the dust and water content and/or independently of the quantity. By virtue of the fact that the separating elements, i.e. here, in particular, the demister, are disposed so as to be inclined until approximately horizontal in the air stream, optimum dewatering of the air stream is ensured, wherein further units disposed downstream may additionally contribute towards an approximately dry air stream leaving the dust separator. It is moreover advantageous that, by virtue of the special arrangement of the demister, clogging of said unit may be avoided because the sludge-containing water continuously drips downwards and may be removed.
According to an advantageous embodiment of the invention, it is provided that a jetwashing device is disposed upstream of the demister. By means of said jetwashing device the demister may be cleaned at regular intervals to ensure that its separation efficiency is also in an optimum range in each case. There is moreover also the possibility of using the jetwashing device to bond yet more dust particles or the residual dust particles with the water shortly before entry into the demister in order also to ensure that all dust particles are actually consolidated and may drain into the water tank.
According to the present invention, the demister is to be disposed as horizontally as possible in the air stream. Depending on the dust content and/or the nature of the dust, it may be advantageous to vary the inclination of the demister. It is therefore particularly advantageous when, according to the present invention, the inclination of the demister is adjustable. To said end, the invention provides that in the inlet region of the washer housing suitable probes check the dust content and the nature of the dust before varying the inclination of the demister either during operation or during breaks in operation. It goes without saying that variation of the inclination may also be advantageous when the dust quantity varies and varies noticeably over extended periods of time.
It was earlier pointed out that it is advantageous to dispose a jetwashing device upstream of the demister, wherein a precise influencing of the air stream is ensured by designing demister and jetwashing device so as to be jointly pivotal by means of a positioning motor. The jetwashing with water or alternatively with other liquids may therefore be effected always from the same angle, with the result that the cleaning effect in particular may be kept within the optimum range.
In order also to ensure a slewing or adjustment of the jetwashing device together with the demister without entailing problems with the water supply, the invention provides that the jetwashing device has a flexible water connection. Here, a piece of hose may be interposed or alternatively turning knuckles, which allow the jetwashing device to move back and forth relative to the corresponding connection pipe.
In the demister, dust-containing sludge water is extensively removed from the air stream. For said purpose, the demister has a suitable filling, wherein according to the invention it is provided that the demister is equipped with a sponge-like woven or braided steel filling. The air stream is repeatedly deflected by said woven steel material so that the sludge particles are acted upon accordingly and separated from the air by the impact energy. They are then carried along by the water and drain into the tank where the sludge separates from the water, thereby allowing the water to be recycled. As tests have demonstrated, said woven or braided steel material is eminently suitable for reliable collection of water drops carrying even superfine dust particles and their separation from the air stream.
Depending on the nature or condition of the dust, it is advantageous to add e.g. tension-relieving agents to the water. For said purpose, the invention provides that the water nozzles are disposed so as to project counter to the inflow direction of the dust-containing air and are connected to a supply pump, which is disposed between water nozzles and water tank and at the same time has an intake connection to an additional tank for water additives. First of all, the water nozzles by virtue of their clever arrangement ensure that the water droplets may bond very easily and reliably with the dust particles, wherein said bonding is improved by the water additives, i.e. for example, tension-relieving agents. The supply pump in said case removes the required quantity of water additives from the additional tank, mixes it simultaneously with the water and sprays said mixture counter to the air stream. An intimate bonding of the dust particles with the water is ensured and, with it, also a collection in the demister and a discharge from the air.
In the case of particularly tenacious dust which because of its origin or other influences is difficult to wet, it may be advantageous when, in addition to the water nozzles, further spray nozzles are arranged distributed over the flow path in the washer housing. In particular, said spray nozzles are connected in such a way that they simultaneously operate only when needed and otherwise remain inoperative.
The water removed from the air stream by the demister and the downstream units passes into the water tank and from there back into circulation. Naturally, a certain water loss is bound to occur and has to be replaced in the circuit. According to the invention, this is achieved in that the water tank
Both Reinhold
Haubold Christian
CFT Gmbh Compact Filter Technic
Creighton Wray James
Narasimhan Meera P.
Smith Duane S.
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