Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to devices for
stirring fluids and may be widely used in cases when
need arises to carry out washing, cleaning or mixing
operations involving thorough agitation of fluids. This
invention can be used to advantage in various fields of
industry: in mining, for instance, to enrich mineral products,
in chemistry, for example, to make suspensions, stir pulp,
for dispersing and degreasing, in food industry, to conduct
diffusion cooking, in light industry, for instance, to treat
leather or raw textile materials in fluids, in agriculture,
for instance, to clean vegetables, in machine-building
industry, for instance, to cleanse machine parts, in domestic
facilities and other fields of industry, to intensify mass
transfer processes.
The problem of intensive and uniform agitation of
fluids has long been of interest for specialists in various
fields of engineering. Mixers used for a long time and up
to now comprise usually a rotatable shaft carrying blades
for agitation of fluid. However, the devices of this kind
turn to be too inefficient and their use is found inexpedient
in some cases, for example, in mining for enrichment of
mineral products, when need arises to stir large quantities
of water together with raw materials. Besides, the flow of
mixture produced by such mixers or impellers is characterized
by great non-uniformity in composition and velocity.
Therefore, a continuous search for new fluid-stirring methods
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and devices has been conducted. Known in the art is a widely
used device comprising a spring-mounted frame carrying a
vessel with fluid and provided with special high-power vi-
brators designed to cause vibrations of this frame and
hence agitation of the fluid. The device of this type,
however, features a high power demand and short service
life of the vessel filled with fluid and subjected to
considerable vibrations. This makes the specialists con-
tinue a search for new mixing devices. A novel device came
into being in the last decade, which is noted for its
simplicity, reliability, high output and comparatively low
specific power consumption.
This device is actually a tubular chamber divided
by a rigid annular partition into two sections. Each section
of the chamber comprises a resilient membrane installed co-
axially with the tubular chamber shell so that a câvity is
formed in the gap between the membrane and shell, which is
connected with a gas ~edium source. If the gas medium is
alternately supplied into the cavities so that a certain
pressure difference is built up, the resilient membranes
will o~cillate in the sections, thereby causing movement
and agitation of the fluid within the tubular chamber.
(See, for instance, the USSR Inventor~s Certificate ~o.
484012 of 1972 "Device to Cause Low-Frequency Oscillations
in Fluidl'). Although this novel device ensures a high
energy concentration of low-frequency oscillations per
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volume unit and uniform distribution of the energy
throughout the chamber volume and, hence, a uniform
agitation of the fluid, the device ~uffers from a number
of disadvantages inherent in it~ design.
One inherent disadvantage of the most intrinsic
character consiats in that the resilient membrane in~talled
inside the shell with a gap relative to the wall has several
degrees of freedom~ which cause~ high-degree modes of membrane
oscillations, resulting in a decrease of transfer of low-
frequency oscillations to the fluid and, hence, in an
impairment of the mixing process. Moreover, the gas medium
inlet hole may be blocked by the resilient membrane, which
will render it impossible to change pressure inside the
cavity as required and will promote wear of the membrane.
,~
It is known that attempt~ were made to use ~uch
fluid-stirring devices in~installations for treatment
(primarily for purification) of loose materials~ Such an
installation consists o-f a number of above deacribed fluid-
~tirring devices arranged in series according to the flow
~,
2Q and provided with a ga~ medium source to actuate said
membranes and with a hopper for loading loose materials
into the first of the said chambers.
However, such in~tallations are not reliable in
service due to the above ~tated dIsadvantages inherent in
the fluid-stirring device~ of that type.
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It is an object of the present invention to
provide a fluid-stirring device, in which low-frequency
oqcillations of the membrane predominantly in the zero
mode are induced.
Another object of the invention is to raise the
efficiency and enhance the reliability of the fluid-stirring
device.
Among other objects of the present invention it
should be particularly emphasized the possibility of
attaining maximum amplitude of low-frequency oscillations
in a device of the described type provided with a membrane
inside a tubular chamber.
A further object of the present invention is to
provide a more reliable and efficient installation for
treatment of materials in a flow of agitated fluid.
These and other objects of the invention have been
accomplished by providing-a fluid-stirring device which
comprises a tubular chamber filled with agitated fluid,
said chamber being divided by a rigid annular partition
into two sections each accommodating a resilient membrane
disposed coaxially with a gap relative to the in~ide
surface of the shell and forming a cavity in the gap com-
municating with a gas medium source which is used to al-
ternately supply the gas medium at a variable pressure
to build up a certain pressure difference between the ~aid
sections and to move the resilient membrane, thereby causing
agitation of the fluid. According to the invention, each
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section accommodates also a rigid perforated bearing member
installed co-axially in the cavity between the membrane
and the tubular chamber shell at a certain distance
from the chamber wall 80 that the membrane rests on
its bearing memker, when no gas medium is supplied into
the cavity.
The arrangement of the resilient membEanes
on the perforated bearing members makes it possible to
define the minimum volume of each gas-filled cavity
and reduce wear of the resilient membranes. In this case
the membranes will contract and expand symmetrically,
and oscillations induced by the membranes will be
substantially of the zero de. All these innovations
contribute to the efficiency and operating reliability
of the device.
It is expedient to hold the membrane~tight
against the perforated bearing member in the upper part
in order to concentrate the energy of oscillations at
the lower part of the cavity, which is of a paramount
importance for simultaneous agitation of the fluid and
transfer of the material from one section to another.
To increase the reliability of the device,
it is worth-while to connect at least one of the sections
of each tubular chamber with a receiver to contain part of
the fluid bled from the chamber in case of an excessive
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pressure. This receiver may be connected with the tubular
chamber interior via a hole made in the vicinity of the
annular partition. According to one of the exemplary
embodiments, excessive fluid is bled into an enlargement
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of the chamber used as a receiver and communicating with
the chamber interior via a through slot made in the upper
part of the chamber shell. A similar slot may be used
for loading loose materials to be treated by the agitated
fluid in the device.
An installation for treatment of loose materials
in a flow of agitated fluid may be constructed by using
the above described devices arranged in succession in
the direction of the flow and representing chambers pro-
vided with membranes actuated under the effect of a gas
medium supplied at a variable pressure, with a perforated
bearing members disposed as described above, and with
a hopper for loading loose materials into the first of
said tubular chambers. The membrane of at least the
first section initially receiving the loose materials should
be held motionless in the upper part.
It is preferable that the first section of the in-
stallation be connected with the hopper through the medium
of a special pneumatic vibratory-type feeder which is
a tubular member accommodating a resilient membrane
installed co-axially with the tubular member shell with
a certain gap from the latter to form an annular cavity
connected with the same gas medium source used to supply
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wor'~ing medium into the said fluid-stirring devices.
The installation of this kind will incorporate
all the advantages of the above described chambers. The
provision of said hopper in conjunction with the pneuma~ic
vibratory-type feeder assures continuous and reliable
operation of the installation. In addition, it is worth-
while mentioning that the pneumatic vibratory-type feeder
is actuated by the gas medium supplied from the same gas
medium source as the fluid-stirring devices, which makes
the construction and operation of the entire installation
much simpler.
Specific embodiments of the invention will now
be described by way of example with reference to the
accompanying drawings, in which:
Fig. 1 is a vertical sectional view, partly
in elevation, showing a fluid-stirring device embodying
the invention,
Fig. 2 is a cross section on the line II-II of
Fig. 1,
Fig. 3 is a vertical sectional view, partly
in elevation, showing a fluid-stirring device with a
membrane held motionless at the top,
Fig. 4 is a cross section on the line IV-IV of
Fig. 3,
Fig. 5 is a version of the fluid-~tirring device
provided with a means for bleeding excessive fluid in
operation,
Fig. 6 shows a version of the installation for
treatment of loose materials in a flow of agitated fluid,
Fig. 7 shows another version of the installation
for treatment of loose materials in a flow of agitated fluid.
Figures 1 and 2 show general views of the fluid-
stirring device.s which can be used to advantage for washing
piece items, for instance, for washing contaminated engines.
It can be also used for washing dirty parts of machinery,
machine and hand tools. The inventory concept underlying
the design of each device can be used as a basis for
construction of domestic ~;ashing machines. The device marked
in general with numeral 1 (Figs 1 and 2) comprises a tubular
chamber 2 divided by a rigid annular partition 3 into two
structurally identical sections 4. Installed in each section
4 is a resilient membrane 5 made of an elastic material
whose modulus of elasticity allows expansion and contraction
of the membrane at a preset amplitude. The ends of each
membrane are flanged outside to form collars 6 held tight
against the end faces of the shell 7 of the tubular chamber
~ and the rigid annular partition 3. The resilient membrane
5 i5 installed so that an annular gap is formed hetween
the membrane and the shell 7 of the tubular chamber 2.
The abo~e described flanged joints and method of installation
of the membrane 5 result in formation of ca~ity ~ communica-
ting with a gas medium source (not shown in the figure) via
a special slide valve arrangement 9 and pipes A and B.
7~ 8
One of the pipes is intended to deliver gas medium (air)
into the cavities, the other, to evacuate air from the
cavities.
The slide valve arrangements 9 are synchronized
functionally so that when one of them is open to supply
compressed air into the cavity of one chamber section,
the other is set to evacuate the contents of the cavity of
the other chamber section. As a result of alternating
delivery and discharge of air the membranes 5 execute
oscillatory motion ensuring agitation of the fluid supplied
into the tubular chamber 2. A cylindrical perforated
bearing member 10 made of a strong material, preferably of
steel, is disposed co-axially between the membrane 5 and
shell 7 of the tubular chamber 2. Perforations 11 are spaced
uniformly all over the surface of the beaxing member 10,
except the member area 12 where
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the gas medium is admitted into the cavity 8. It goes
without saying that the cylindrical configuration of the
bearing member 10 is not insisted upon, its shape being
dictated by the configuration of the shell 7, tubular
chamber 2 and membrane 5. But it is imperative that this
member 10 be disposed co-axially with the shell 7 of the
tubular chamber 2. The above described device may be
advantageously used for cleaning bulky parts attached
appropriately inside the chamber section 4. The part sus-
pension system does not form the subject matter of this
application and may be designed depending on the size,
shape and other characteristics of the particular item
to be cleaned.
It is difficult, however, to keep loose materials
in suspended state, they will tend to accumulate in the
bottom part of the tubular chamber 2. Therefore, it is
expedient to ensure that the lower part of the membrane
5 oscillates at a higher degree. Shown in Figs. 3 and 4
is a fluid-stirring device of that particular type, whose
component parts identical with those of the device shown
in Figs. 1 and 2 are indica~ed by the same reference nume-
rals. The only difference between the device shown in
Figs. 3 and 4 and that presented in Figs. 1 and 2 consists
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in that the membrane 5 is held firm at the top by a strip
13. Needless to say that the uppex part of the membrane
5 thus secured remains motionless, and energy of oscillations
is transmitted only from the lower part, thereby improving
the conditions for treatment of loose materials.
Covers 14 are provided in the devices shown
both in Figs. 1 and 2 and Figs. 3 and 4 to close the ends
of the tubular chamber 2. One of the covers has a hole 15
closed with a plug 16 and used to pour fluid into the
chamber.
To operate the proposed device for washing
a bulky part, proceed as follows: install the part (not
shown) inside the tubular chamber 2, reinstall the covers
14 and pour washing fluid into the hole 15. Close the
hole 15 with the plug 16. Operate the gas medium source
to supply the gas medium through the slide valve arrangement
9 into the cavity 8 of one section 4 and evacuate the gas
medium from the cavity of the other section 4. Suppose
the gas medium is initially delivered into the left-hand
2Q section 4 to pass through the holes 11 in the perforated
bearing member 10 and deflect the membrane to the axis
of the section 4. Since air is simultaneously evacuated
from the cavity 8 of the right-hand section 4, a pressure
difference is built up. The fluid flows from one section
4 into the other via the annular partition 3. The oscillation
frequency of the membranes 5 in the two sections 4 is set
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in accordance with the resiliency of the membranes and
the mass cf the fluid to be agitated. The membranes 5
actuated in succession execute an oscillatory motion with
a phase shift up to 180, which makes it possible to localize
the oscillatory motion of the fluid within the confines of
the tubular chamber 2 and ensure agitation of the fluid.
The above described device offers satisfactory
performance in case the chamber is but partially filled with
the fluid so that a sufficient air space is left to permit
maximum displacement of the fluid.
However, the fluid-stirring device provided with
the rigid strip holding the membrane and reducing its working
area does not permit of high power generation within the
entire installation. Therefore, it is proposed to make
use of a fluid-stirring device with a tubular chamber filled
to capacity, in which case one of the sections 4 of the
tubular chamber 2 must be connected with a void designed
to receive some fluid, if an excessive rise of pressure
occurs.
Fig. 5 shows a device capable of attaining
maximum power, which is substantially similar in construction
with those shown in Figs. 1, 2, 3 and 4. Ide~tical componen~
parts are marked in Fig. 5 with the same reference numerals
as in Figs. 1, 2, 3 an~ 4. The only differerlce consists
in that a through hole 17 is made in the rigid annular
partition 3 ~o intercommunicate the interior of the tubular
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chamber 2 and receiver 18 (for instance, a bellows) via a
tube 19. The fluid-stirring device provided with a receiver
is operated baslcally in the same way as the devices previously
described. The pressure arising due to contraction of the
membrane within the section 4 in the tubular chamber 2 filled
with the fluid to capacity is kept at minimum, because part
of the fluid is transferred into the receiver 18.
The fluid-stirring device under consideration may
be used for construction of an installation for treatment
of loose materials. The installation illustrated in Fig. 6
consists of a number of similar tubular chambers 2 constructed
substantially as the chamber described hereinabove with
reference, for example, to Figs. 3 and 4. The membrane 5 in
the left-hand section 4 of each tubular chamber is held firm
against the shell 7 at the top, while the membrane 5 in the
right-hand section 4 of each tubular chamber is free to move
in the upper part. A through slot 20 is made throughout
the shell and perforated member in the upper part of the
left-hand section of each tubular chamber~ A hopper 21 is
installed above the slot in one of the tubular chambers
and receivers 22 used to relieve the chamber of fluid over-
pressure axe mounted above the slots on the top of al] the
succeeding chambers. Fluid is supplied through a pipe 23
connected to the cover 14 of the tubular chamber 2. Let us
consider the operation of this instal~ation in brief,
s~pposing the operation of the tubular chambers proper is
clear from the foregoing description. Loose material poured
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into the hopper 21 and entrained by the fluid found in
the tubular chamber 2, moves from one section 4 to the
following one together with the fluid flow, being treated
by the fluid at the same time. The number of the tubular
chambers is chosen depending on the required treatment
conditions (cleaning, mixing, etc.). Loose material of the
desired characteristics is obtained at the outlet of the
last section.
Shown in Fig. 7 is another practical version of
the installation, comprising a large number of the tubular
chambers 2 and functioning as described hereinabove. The
loading hopper 35 of the installation is connected to the
left-hand section of the first tubular chamber 2 through
the medium of a pneumatic vibratory-type feeder 24. The
membrane of the first section of this chamber is likewise
held motionless at the top. The pneumatic vibratory-type
feeder 24 is made in the form of a tubular member 25
contain7ng a membrane 26 of an elastic material allowing
the membrane to contract and expand alternately at a
predetermined amplitude~ The ends of the membrane 26 are
flanged outside to form collars 27 tightened up by the
flanges 28 of the tubular member 25. The membrane 26 is
disposed inside the tubular member 25 with a certain gap.
Due to these flanged joints and respective location of the
membrane 26 a cavity 29 is formed to receive the gas medium
supplied through the s~ide valve arrangement 3~. A bearing
member 31 with its side surface perforated is disposed
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between the membrane and shell of the tubular member 25.
Perforations 32 are spaced uniformly all over the side surface
of the bearing member 31, except the member area 33 where
the gas medium is admitted into the cavity. The membrane
26 is held tight against the shell in the upper part by
means of a strip 34. The upper part of the tubular member
25 is cut away, the tubular member side edges are pressed
tight against the outside surface of the bearing member 31,
in which case the exposed area of the bearing member 31 is
not perforated.
Loose material is loaded into this installation in
the following way. From the hopper 35 loose material and
washing fluid are poured into the tubular member 25 of the
pneumatic vibratory-type feeder 24. Gas medium is simulta-
neously supplied into the cavity 29 by means of the slide
valve arrangement 30. The gas medium a' a variable pressure
passes through the holes 32 in the perforated bearing member
31, changing the preseure inside the cavity 29 from a high
surplus pressure to rarefaction, thereby causing the membrane
26 to oscillate. When the membrane 26 contracts inside the
tubular mem~er 25, the loose material is pushed along the
feeder under the gravity effect. When the membrane 26 expands,
the loose material moves under gravity from the hopper 35 into
the pneumatic vibratory-type fe~der 24, filling the vacated
space. The operating principle of the installation shown
in Fig. 7 does not differ much from that of the installation
presented in Fig. 6. It should be emphasized that the membrane
of the feeder must be held motionless in the upper part to
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ensure better results in treatment of loose materials.
While the invention has been described in but several
preferable embodiments, it will be obvious to those skilled
in the art that it is susceptible of various changes and
modifications without departing from the spirit of the
present invention.
For example, the upper part of the shell 7 (see Figs. 1
and 3) of the tubular chamber 2 may be cut away, the shell
side edges may be pressed tight against the outside surface
of the bearing member 10, in which case the exposed area
of the bearing member 10 is not to be perforated and a more
uniform distribution of pressure on the membrane surface is
achieved.
In the proposed device the perforated bearing member
is supposed to be made from stainless steel, but it is evident
for those skilled in the art that use can be made of any
other material strong enough to withstand the membrane pressure.
The rnembrane is actuated by a gas medium, for instance, by
compressed air. It is obvious that the kind of the gas medium
is determined by the field of application of the above described
devices.
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