U.S. patent application number 14/358623 was filed with the patent office on 2014-10-30 for restrictor and production process of a fluid leakage restrictor for aerostatic bearings.
This patent application is currently assigned to WHIRLPOOL S.A.. The applicant listed for this patent is Dietmar Erich Bernhard Lilie, Henrique Bruggmann Muhle. Invention is credited to Dietmar Erich Bernhard Lilie, Henrique Bruggmann Muhle.
Application Number | 20140318365 14/358623 |
Document ID | / |
Family ID | 47471417 |
Filed Date | 2014-10-30 |
United States Patent
Application |
20140318365 |
Kind Code |
A1 |
Muhle; Henrique Bruggmann ;
et al. |
October 30, 2014 |
RESTRICTOR AND PRODUCTION PROCESS OF A FLUID LEAKAGE RESTRICTOR FOR
AEROSTATIC BEARINGS
Abstract
Restrictors (16,17) for aerostatic bearings capable of ensuring
a constant flow, regardless of their size and dimensional
tolerance, such that the gas flow is adjusted by deforming their
internal section. A process for the production of restrictors
(16,17) for aerostatic bearings with respect to ensuring the gas
flow values desired is also provided.
Inventors: |
Muhle; Henrique Bruggmann;
(Joinville, BR) ; Lilie; Dietmar Erich Bernhard;
(Joinville, BR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Muhle; Henrique Bruggmann
Lilie; Dietmar Erich Bernhard |
Joinville
Joinville |
|
BR
BR |
|
|
Assignee: |
WHIRLPOOL S.A.
Sao Paulo, SP
BR
|
Family ID: |
47471417 |
Appl. No.: |
14/358623 |
Filed: |
November 14, 2012 |
PCT Filed: |
November 14, 2012 |
PCT NO: |
PCT/BR2012/000451 |
371 Date: |
May 15, 2014 |
Current U.S.
Class: |
92/153 ;
29/407.05; 417/415; 72/367.1 |
Current CPC
Class: |
F04B 39/126 20130101;
F04B 53/166 20130101; F16C 29/025 20130101; B21D 31/06 20130101;
F04B 53/18 20130101; Y10T 29/49771 20150115; F16C 32/0622 20130101;
F04B 39/122 20130101; F04B 35/045 20130101; F04B 35/04 20130101;
F04B 53/162 20130101 |
Class at
Publication: |
92/153 ;
29/407.05; 417/415; 72/367.1 |
International
Class: |
F04B 53/18 20060101
F04B053/18; F04B 35/04 20060101 F04B035/04; B21D 31/06 20060101
B21D031/06 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 16, 2011 |
BR |
PI1105471-9 |
Claims
1.-27. (canceled)
28. A flow restrictor (16,17) of a fluid for aerostatic bearings of
linear compressors wherein the restrictor (16,17) is obtained
through a deformation process of at least a portion of its inner
section, the deformation being by obtained flattening or folding or
blowing.
29. A flow restrictor (16,17) of a fluid for aerostatic bearings of
linear compressors according to claim 28, wherein the deformation
is punctual or partial or total.
30. A flow restrictor (16,17) of a fluid for aerostatic bearings of
linear compressors according to claim 29, wherein the deformation
is simultaneously partial and punctual.
31. A flow restrictor (16,17) of a fluid for aerostatic bearings of
linear compressors according to claim 30, wherein the restrictor
(16,17) is made of metallic material.
32. A flow restrictor (16,17) of a fluid for aerostatic bearings of
linear compressors according to claim 31, wherein the restrictor
(16,17) is made of polymeric material.
33. A flow restrictor (16,17) of a fluid for aerostatic bearings of
linear compressors according to claim 32, wherein the restrictor
(16,17) is made of glass-ceramic material.
34. A flow restrictor (16,17) of a fluid for aerostatic bearings of
linear compressors according to claim 33, wherein the restrictor
(16,17) is a microtube.
35. A production process of a fluid flow restrictor (16,17) for
aerostatic bearings of linear compressors, said production process
comprising: i) deforming an internal section of a restrictor
(16,17) in at least a portion of the restrictor (16,17); ii)
measuring a flow value of a fluid in the restrictor (16,17); iii)
comparing the flow value of a fluid measured with a value
previously specified; iv) returning to stage i) if the flow value
of the fluid is outside specification with respect to said value
previously specified.
36. A production process according to claim 35, wherein between
stage i) and stage ii) there is an intermediary stage which
provides for a waiting time for an elastic return of its deformed
portion.
37. A production process according to claim 35, wherein in stage i)
the deformation is carried out by any type of process of plastic
shaping.
38. A production process according to claim 35, wherein in stage i)
the deformation is carried out by flattening.
39. A production process according to claim 35, wherein in stage i)
the deformation is carried out by folding.
40. A production process according to claim 35, wherein in stage i)
the deformation is by blowing.
41. A production process according to claim 35, wherein in stage i)
the deformation is total.
42. A production process according to claim 35, wherein in stage i)
the deformation is partial.
43. A production process according to claim 35, wherein in stage i)
the deformation is punctual.
44. A production process according to claim 35, wherein in stage i)
the deformation is simultaneously partial and punctual.
45. A production process according to claim 35, wherein in stage i)
the deformation is carried out by flattening.
46. A compressor comprising a flow restrictor of a fluid for an
aerostatic bearing, wherein the restrictor is obtained through a
deformation process of at least a portion of its inner section, the
deformation being by obtained flattening or folding or blowing.
Description
[0001] The present invention pertains to restrictors for aerostatic
bearing of pistons in cylinders comprised by linear compressors for
cooling.
DESCRIPTION OF THE STATE OF THE ART
[0002] In general terms, the basic structure of a cooling circuit
comprises four components, namely the compressor, the condenser,
the expansion device and the evaporator. These elements
characterize a cooling circuit in which a fluid circulates so as to
allow the temperature of an internal environment to decrease,
withdrawing the heat therefrom and displacing it to an external
environment by way of the elements that make up the cooling
circuit.
[0003] The fluid that circulates in the cooling circuit generally
follows the passage sequence: compressor, condenser, expansion
valve, evaporator and compressor again, thus characterizing a
closed cycle. During circulation, the fluid undergoes variations of
pressure and temperature which are responsible for changing the
state of the fluid, which may be in gaseous or liquid state.
[0004] In a cooling circuit, the compressor act as the heart of the
cooling system, creating the flow of the cooling fluid along the
system components. The compressor raises the temperature of the
cooling fluid by increasing the pressure provided on its inside and
forces the circulation of this fluid in the circuit.
[0005] Therefore, the importance of a compressor in a cooling
circuit is undeniable. There are various types of compressors
applied in cooling systems, and in the field of the current
invention, attention will be focused on linear compressors.
[0006] Due to the relative movement between the piston and the
cylinder, the bearing formation of the piston is necessary. This
bearing formation consists of the presence of a fluid in the gap
between the external diameter of the piston and the internal
diameter of the cylinder, preventing contact between them and the
consequent premature wear and tear of the piston and/or cylinder.
The presence of the fluid between the two components referred to
also serves to decrease attrition between them, meaning the
mechanical loss of the compressor is minor.
[0007] One of the forms of piston bearing formation is by way of
aerostatic bearings which, in essence, consists of creating a gas
cushion between the piston and the cylinder so as to avoid wear and
tear between these two components. One of the reasons for using
this type of bearing formation is justified by the fact that the
gas has a much lower viscosity attrition coefficient than oil,
contributing such that the energy dissipated in the aerostatic
bearing formation system is much lower than that of a lubrication
with oil, whereby achieving improved yield of the compressor.
[0008] The gas compression mechanism operates by the axial and
oscillatory movement of a piston inside a cylinder. At the top of
the cylinder is the head, jointly with the piston and the cylinder
forming a compression chamber. In the head, the discharge and
suction valves are positioned. These valves regulate the inflow and
outflow of gas in the cylinder. In turn, the piston is driven by an
actuator which is connected to the linear motor of the
compressor.
[0009] The piston of the compressor driven by the linear motor has
the function of developing an alternative linear movement, meaning
the movement of the piston inside the cylinder exerts a compression
action on the gas let in by the suction valve, up to the point
where it can be discharged to the high pressure side, through the
discharge valve.
[0010] For the correct working of an aerostatic bearing formation,
it is necessary to use a flow restrictor between a high pressure
region which externally involves the cylinder and the gap between
the piston and the cylinder. This restriction serves to control the
pressure in the bearing formation region and to restrict the gas
flow.
[0011] Among the various possible solutions, it is common to use
the very gas of the cooling circuit for the aerostatic bearing
formation of the piston. Therefore, all the gas used in the bearing
formation represents a loss of efficiency of the compressor, since
the gas is diverted from its original function, which is to
generate cold in the evaporator of the cooling system. Accordingly,
it is desirable that the gas flow of the bearing formation be as
low as possible so as not to compromise the efficiency of the
compressor.
[0012] In essence, restricting the gas flow is dependent on the
length and size of the internal diameter of the restrictor. For a
certain size, the bigger the cross section to the gas flow, that
is, the bigger the internal diameter, the lower the restriction
imposed on the gas flow. Based on these two variables (cross
section to the flow and length) it is possible to obtain a loss of
load necessary for any bearing restrictor of the compressor.
[0013] The microtubes available commercially on the market present
very large tolerances in relation to the nominal internal diameter.
This variation of the internal diameter may cause a very large
variation in the restriction on gas flow and, consequently, of the
flow between one restrictor and the other. This type of occurrence
causes an imbalance in the bearing, chiefly if this variation
occurs between restrictors present in the same section of the
cylinder.
[0014] Although a flow variation between restrictors in a same
section is undesirable, there is a need for the restrictors present
in the top region of the cylinder to have greater flows than the
restrictors present in the lower part of the cylinder. This is
because the piston suffers with the loss of support when it is in
top dead center due to the high pressure existing in the
compression chamber. Accordingly, there is a need to provide
restrictors with different restrictions to the gas flow to these
two regions of the cylinder.
[0015] In any case, a solution has not yet been found to guarantee
the production of restrictors based on constant-flow microtubes.
To-date, the characteristic evaluated in the productive process is
the internal diameter value which, as already explained, due to the
technologies applied in its production and existing respective
tolerances, do not guarantee an equal flow between different
restrictors.
[0016] Thus, there are currently no restrictors whose quality
control is made by virtue of its restriction capacity, but rather
on account of its dimensions. In other words, the present invention
manages to achieve a production of restrictors that may differ from
each other in terms of their dimensions, but that guarantee a same
flow.
OBJECTIVES OF THE INVENTION
[0017] It is, therefore, an objective of the present invention to
provide restrictors for aerostatic bearings capable of guaranteeing
a constant flow, regardless of its size and dimensional
tolerance.
[0018] A further objective of the present invention is to provide
restrictors for aerostatic bearings whose flow is adjusted by means
of deformation of its internal section.
[0019] It is yet a further objective of the present invention to
provide a process capable of guaranteeing the production of
restrictors for aerostatic bearings with respect to guaranteeing
desired flow values.
BRIEF DESCRIPTION OF THE INVENTION
[0020] The objectives of the present invention are achieved by
providing a flow restrictor tube of a fluid for aerostatic
bearings, and the restrictor is obtained through a deformation
process of at least a portion of its inner section.
[0021] The objectives of the present invention are also achieved by
providing a flow restrictor of a fluid for aerostatic bearings of
linear compressors, and the restrictor has at least a portion of
its inner section deformed.
[0022] Lastly, the objectives of the present invention are achieved
through a production process of a flow restrictor of a fluid for
aerostatic bearings of linear compressors which comprises the
stages of:
[0023] i) deforming the internal section of the restrictor in at
least a portion of the restrictor;
[0024] ii) measuring the flow of a fluid in the restrictor;
[0025] iii) comparing the flow value of a fluid measured with the
value previously specified;
[0026] iv) returning to stage i) if the flow value of the fluid is
outside the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The present invention will now be described in greater
detail based on examples represented in the drawings. The drawings
show:
[0028] FIG. 1--is a cross-sectional view of a linear
compressor.
[0029] FIG. 2--is a cross-sectional view of a restrictor of the
state of the art.
[0030] FIG. 3 a--is a cross-sectional view of restrictors of the
present invention endowed with punctual constriction.
[0031] FIG. 3 b--is a cross-sectional view of restrictors of the
present invention endowed with partial constriction.
[0032] FIG. 3 c--is a cross-sectional view of restrictors of the
present invention endowed with total constriction.
[0033] FIG. 3 d--is a cross-sectional view of restrictors of the
present invention endowed with fold constriction.
[0034] FIG. 4--is a cross-sectional view of a constriction or
kneading.
[0035] FIG. 5--is a cross-sectional view of restrictors of the
present invention with combinations of types of
kneading/constrictions and fold.
[0036] FIG. 6--is a view of an example of a system of regulating
restrictors at rest.
[0037] FIG. 7--is a view of an example of a system of regulating
restrictors at work.
DETAILED DESCRIPTION OF THE DRAWINGS
[0038] The present invention proposes a technological advance both
in the level of the restrictors (better known by persons skilled in
the art as restrictor tubes/microtubes), as well as a productive
process capable of producing the restrictors with the desired fluid
flow characteristics.
[0039] According to the principle of working of a cooling circuit
and as presented in FIG. 1, preferably the gas compression
mechanism occurs by the axial and oscillatory movement of a piston
1 inside a cylinder 2. At the top of the cylinder 2 is a head 3
which jointly with the piston 1 and the cylinder 2 form a
compression chamber 4. In the head 3 there are positioned the
discharge 5 and suction 6 valves which regulate the inflow and
outflow of gas in the cylinder 2. It is also noted that the piston
1 is driven by an actuator 7 linked to the linear motor of the
compressor. No further explanations are provided on this motor in
this document.
[0040] The piston 1 of a compressor, when driven by the linear
motor, has the function of developing an alternative linear
movement, promoting a movement of the piston 1 inside the cylinder
2 which exerts compression action on the gas let in by the suction
valve 6 up to the point where the gas can be discharged to the high
pressure side, by way of the discharge valve 5.
[0041] The cylinder 2 is mounted inside a block 8 and on the head 3
there is mounted a lid 9 with the drain valve 10 and the suction
valve 11, which connect the compressor to the rest of the
system.
[0042] As referred to, the relative movement between piston 1 and
cylinder 2, the bearing formation of the piston 1 is necessary,
consisting of the presence of a fluid in the gap 12 between the two
parts, with the purpose of separating them during movement.
[0043] An advantage of using the gas itself as lubricant fluid is
the absence of an oil pumping system.
[0044] Preferably, the gas used for the bearing formation can be
the gas itself pumped by the compressor and used in the cooling
system. Once compressed, this gas is diverted from the discharge
chamber 13, from the lid 9 through the channel 14 to the high
pressure region 15 around the cylinder 2, and the high pressure
region 15 is formed by the external diameter of the cylinder 2 and
internal diameter of the block 8.
[0045] From the high pressure region 15 the gas passes through the
restrictors 16,17 inserted in the wall of the cylinder 2, towards
the gap 12 existing between the piston 1 and cylinder 2, forming a
cushion of gas which prevents the contact between the piston 1 and
cylinder 2.
[0046] As mentioned, with the aim of restricting the gas flow
between the high pressure region 15 and the gap 12, it is necessary
to make use of a restrictor 16,17. This restriction serves to
control the pressure in the bearing formation region and to
restrict the gas flow, since all the gas used in the bearing
formation represents a loss of efficiency of the compressor, as the
primary function of the gas is to be sent to the cooling system and
to generate cold. Accordingly, it is worth emphasizing that the gas
diverted to the bearing formation should be the minimum possible so
as not to compromise the efficiency of the compressor.
[0047] To keep the balance of the piston 1 inside the cylinder 2,
preferably at least three restrictors 16,17 are necessary in a
given section of the cylinder 2 and at least two sections of
restrictors 16,17 are necessary in the cylinder 2. The restrictors
should be in such opposition that even with the oscillation
movement of the piston 1 the restrictors 16,17 are never
discovered, that is, that the piston 1 does not leave the actuation
area of the restrictor 16,17.
[0048] With the aim of controlling the flow of the restrictors
16,17 and of guaranteeing that all the restrictors 16,17 of a same
section of the cylinder 2 present the same gas flow, it is possible
to start with restrictors having flows slightly above that
specified, that is, with an internal section value higher than that
specified, and measure the flow at the same time in which a
constriction or kneading (plastic deformation) in generated in the
restrictor 16,17 itself with the aim of decreasing the flow.
Accordingly, it is possible to use tubes/microtubes, such as, for
example, those used to manufacture hypodermic needles, for
electroerosion tools, among others.
[0049] Once the specified flow is achieved, the plastic deformation
ceases. Accordingly, the flow of each restrictor 16,17 is
regulated, and may also, from a same restrictor 16,17, generate
restrictors 16,17 with deliberately different flows when such need
arises (such as, for example, in the top region of the cylinder
2).
[0050] It is thus possible to guarantee restrictors 16,17 with
equal flows or with minimal differences by way of the principle of
increasing the loss of load by decreasing the cross section area to
the gas flow. This effect can be obtained by way of a constriction
that decreases the internal diameter of the restrictor 16,17, or
simply by kneading (see FIG. 3). In the case of kneading, although
not resulting in a circular-shaped section, but rather flattened,
an effect of increasing the loss of load is achieved, and
consequent decrease of the flow (see FIG. 4). Other ways of
decreasing the internal section area can also be used, such as a
fold, for example.
[0051] FIG. 3 illustrates some examples of how to apply the plastic
deformation. This can be located in a single point of the
restrictor (see FIG. 3a), as well as occupying a certain length of
the restrictor (see FIG. 3b) or even be done along all or almost
all the length of the restrictor (see FIG. 3c). Such as referred
to, the formation of folds (see FIG. 3d) may also generate a
restriction that decreases the gas flow.
[0052] The possibilities of this technology are varied, and the gas
flow can be restricted by the most varied means, and the
deformation imposed upon the material can be carried out, as shown
in FIG. 5, in a punctual, partial, total manner, with folds, by
flattening and by means of any combination thereof. In the case of
partial deformation, there will be at least two different internal
sections from each other for the passage of the fluid. Preferably,
but not compulsorily, the material used is metallic and is of
circular section before deformation. In any case, the material may
present any section other than circular. These characteristics only
depend on the specific needs of each project. Additionally, the
material used may be polymer or glass-ceramics.
[0053] In order to achieve the desired flow value in each
restrictor, a process capable of guaranteeing said specificity has
been developed. With the aim of guaranteeing the maintenance of a
suitable flow variation field between restrictors, the process of
plastic deformation is preferably controlled by the very flow
measured during the process.
[0054] This system may work in closed circuit such that once the
specified flow is reached, the system automatically ceases the
process of plastic deformation. Accordingly, it is well known that,
regardless of the variation of the internal diameter of the
restrictor 16,17, restrictors 16,17 are obtained with controlled
flows, whose variations depend on the accuracy of the system that
generates the plastic deformation, as well as the flow measurement
system. An example of the process is shown in FIGS. 6 and 7.
[0055] FIG. 6 represents the initial stage of the process where the
restrictor 16,17 is found, with its cross section unaltered,
disposed in a system 100 capable of imposing a plastic deformation
100. To the left of the restrictor 16,17 is a source of gas under
pressure. Notably, the system capable of imposing a plastic
deformation 100 is controlled by the flow measurement system
102.
[0056] FIG. 7 shows the working of the process at its deformation
stage. The restrictor 16,17 undergoes a plastic deformation and the
gas source under pressure 101, connected to the restrictor 16,17,
sends a gas flow through the restrictor 16,17 which is connected to
the flow measurement system 102 to take a reading of the flow value
of the restrictor 16,17. This value will be compared to a value
stipulated previously and, after comparing the results, if the flow
value is above that stipulated, a signal is sent to the system that
generates the plastic deformation 100 to proceed with the new
plastic deformation. This process occurs successively and
iteratively until the previously stipulated flow value is achieved.
It is therefore guaranteed that said restrictor 16,17, when put to
work, provides the necessary gas flow for the correct working of
the system.
[0057] Since the deformation imposed upon the restrictor 16,17 may
present an elastic component, causing the occurrence of an elastic
return and which, consequently, the gas flow is above that desired,
it is possible to carry out the process in more than just a single
stage, making it iterative, that is, such that the system makes the
chosen deformation and releases the restrictor 16,17 letting the
deformed region return elastically, during a certain period of time
suitable for it to return, then measuring the gas flow. If the flow
is still not in accordance with specification, the system causes a
new deformation in the restrictor 16,17 and then takes a fresh
reading and so on and successively until the specified flow value
is achieved.
[0058] This process can be carried out with both metal and polymer
materials. Additionally and bearing in mind that the true objective
is to guarantee a deformation of the internal section of the
material, it is possible to employ a process of deformation by
blowing capable of causing a controlled deformation of the
restrictor 16,17.
[0059] Alternatively, it is also possible to use glass-ceramic
materials, deformable by way of a process that feeds the restrictor
with heat up to a softening point of the material (glass transition
temperature--Tg) which enables its internal section to be molded to
a desirable value.
[0060] Besides the techniques of plastic shaping by kneading,
constriction, folding, blowing, it is also possible to use a
technique of hydroforming or any other that is justifiable. It is
further possible, by way of techniques such as hydroforming, to
reverse in an absolutely controlled manner, excess deformation
imposed upon the restrictor 16,17. This process of plastic shaping
also allows the reverse situation to be carried out by deforming it
beforehand from inside to out instead of by imposing compressing
forces on the material.
[0061] Having described examples of preferred embodiments, it
should be understood that the scope of the present invention
encompasses other possible variations, being limited only by the
content of the accompanying claims, potential equivalents being
included therein.
* * * * *