U.S. patent application number 12/742474 was filed with the patent office on 2010-12-23 for expansion valve.
This patent application is currently assigned to DANFOSS A/S. Invention is credited to Kirsten Bladt Nielsen, Jakob Spangberg, Benjamin Thomsen, Anders Vestergaard.
Application Number | 20100320278 12/742474 |
Document ID | / |
Family ID | 40243928 |
Filed Date | 2010-12-23 |
United States Patent
Application |
20100320278 |
Kind Code |
A1 |
Vestergaard; Anders ; et
al. |
December 23, 2010 |
EXPANSION VALVE
Abstract
A thermal expansion valve for a refrigeration system comprises a
working element with a diaphragm clamped between a cover plate and
a cover ring. The diaphragm is a multiple-diaphragm comprising two
or more individual diaphragms. This makes the multiple-diaphragm
more flexible than a single diaphragms and increases the lifetime
of the diaphragm. The individual diaphragms are separated by an
anti-friction layer to protect against tear, the anti-friction
layer can be grease or oil placed between the individual diaphragms
or it can be a layer of coating on the diaphragms.
Inventors: |
Vestergaard; Anders;
(Sydals, DK) ; Spangberg; Jakob; (Nordborg,
DK) ; Thomsen; Benjamin; (Aabenraa, DK) ;
Nielsen; Kirsten Bladt; (Egernsund, DK) |
Correspondence
Address: |
MCCORMICK, PAULDING & HUBER LLP
CITY PLACE II, 185 ASYLUM STREET
HARTFORD
CT
06103
US
|
Assignee: |
DANFOSS A/S
Nordborg
DK
|
Family ID: |
40243928 |
Appl. No.: |
12/742474 |
Filed: |
November 12, 2008 |
PCT Filed: |
November 12, 2008 |
PCT NO: |
PCT/DK2008/000402 |
371 Date: |
September 10, 2010 |
Current U.S.
Class: |
236/92B |
Current CPC
Class: |
F25B 2341/0681 20130101;
F25B 41/31 20210101 |
Class at
Publication: |
236/92.B |
International
Class: |
F25B 41/06 20060101
F25B041/06 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 13, 2007 |
DK |
PA 2007 01606 |
Claims
1-7. (canceled)
8. A thermal expansion valve for a refrigeration system comprising
a working element comprising a diaphragm chamber, a base ring and a
cover plate wherein the diaphragm chamber comprises a
multiple-diaphragm placed between the base ring and the cover
plate, the multiple-diaphragm comprises two or more individual
diaphragms and the individual diaphragms are separated by an
antifriction layer.
9. The thermal expansion valve according to claim 8 wherein the
antifriction layer is grease or oil or another suitable fluid.
10. The thermal expansion valve according to claim 8 wherein the
antifriction layer is rubber or plastic.
11. The thermal expansion valve according to claim 8 wherein the
individual diaphragms comprises a coating.
12. The thermal expansion valve according to claim 11 wherein the
coating is made of carbon, rubber, Teflon or a plastic
material.
13. The thermal expansion valve according to claim 11 wherein the
coating is made of cobber, tin, zinc or another suitable metal or
alloy.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is entitled to the benefit of and
incorporates by reference essential subject matter disclosed in
International Patent Application No. PCT/DK2008/000402 filed on
Nov. 12, 2008 and Danish Patent Application No. PA 2007 01606 filed
Nov. 13, 2007.
FIELD OF THE INVENTION
[0002] This invention relates to a thermal expansion valve for a
refrigeration system comprising a working element with a diaphragm
chamber. The expansion valve has a closure member which is movable
by the force of the working element.
BACKGROUND OF THE INVENTION
[0003] A thermal expansion valve usually comprises a working
element with a diaphragm clamped between a cover plate and a cover
ring. The space above the diaphragm is connected by the way of a
capillary tube to a pressure sensor or a pressure-generating
temperature sensor, the pressure of which loads the diaphragm from
above. The refrigerant pressure prevailing in the valve and a
spring bearing against a plate acts on the diaphragm in the
opposite direction.
[0004] In commercially available thermal expansion valves the
diaphragm element is a single diaphragm made of a single layer of
metal normally steel. The single diaphragm is exposed to stress and
deformation from the forces acting on the diaphragm.
[0005] The stress and deformation with time will wear out the
diaphragm reducing the life time of the valve.
SUMMARY OF THE INVENTION
[0006] The object of this invention is to make a diaphragm element
for a thermal expansion valve for a refrigeration system that can
stand up to the stress and deformation and improve the lifetime of
the diaphragm element.
[0007] The problem is solved according to the invention by
replacing the normal single diaphragm made of a single layer of
metal with a multiple-diaphragm comprising two or more individual
diaphragms.
[0008] A problem with the multiple-diaphragm is cold welding and
wearing between the individual diaphragms. This problem can be
solved by adding an antifriction layer between the individual
diaphragms. The antifriction layer can be a small amount of grease
or oil. Another way to solve this problem is to coat the diaphragms
by a layer of carbon, rubber, plastic or a layer of a metal like
cobber or tin.
[0009] The multiple-diaphragm comprises two or more individual
diaphragms, the individual diaphragms in a multiple-diaphragm are
thinner than a traditional single diaphragm and therefore the
multiple-diaphragm have higher flexibility and are less susceptible
to damage due to stress and deformations and therefore the
multiple-diaphragm has a longer life time.
[0010] This invention is a thermal expansion valve for a
refrigeration system comprising a working element comprising a
diaphragm chamber, a base ring and a cover plate wherein the
diaphragm chamber comprises a multiple-diaphragm placed between the
base ring and the cover plate, the multiple-diaphragm comprises two
or more individual diaphragms.
[0011] The multiple-diaphragm is placed between the base ring and
the cover plate, the multiple-diaphragm is made of two, three or
more individual diaphragms. The advantage is that the individual
diaphragms are thinner than a traditional single diaphragm and
therefore more flexible and less affected by stress, strains and
deformations and therefore it has a longer life time. The
individual diaphragms support each other and therefore the
diaphragms element has the same stiffness as a traditional single
diaphragm.
[0012] Each individual diaphragm is a complete diaphragm and can be
used as a single diaphragm. Therefore if one individual diaphragm
is broken, for instance by loose metal particles left over from the
manufacturing process penetrating the individual diaphragm, then
the other individual diaphragms are still in place and the valve is
still working.
[0013] The individual diaphragms are separated by an antifriction
layer. This is because without an antifriction layer the individual
steel diaphragms can glide against each other and the friction
causes tear and cold welding destroying the individual diaphragms.
To avoid this, a layer of antifriction material is placed between
the individual diaphragms.
[0014] The antifriction layer can be grease or oil or another
suitable fluid. This solves the problem avoiding friction between
the individual diaphragms.
[0015] The antifriction layer can also be rubber or plastic. This
could be a layer of double adhesive tape. This is easier in the
assembly process to place a slice of rubber or tape between the
individual diaphragms than to use grease or oil.
[0016] Instead of placing a layer of grease, oil or some other
material between the individual diaphragms, the diaphragms can be
coated by a suitable material. This makes the assembly process even
easier since no extra material is added during the assembly
process.
[0017] The coating can be made of carbon, rubber or a plastic
material. For instance diamond like carbon or Teflon can be used.
The coating can also be made of cobber, tin, zinc, silver, nickel
or another suitable metal or alloy. Besides protecting against tear
and cold welding coating also makes the diaphragm harder and less
likely to be damaged in case there should be loose metal particles
in the valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The invention is described in further detail hereinafter
with reference to a preferred embodiment illustrated in the
drawings, in which
[0019] FIG. 1 shows a valve according to this invention.
[0020] FIG. 2 shows the working element according to this
invention.
[0021] FIG. 3 shows an exploded view of the working element in FIG.
2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] In the embodiment described the multiple-diaphragm comprises
two individual diaphragms. But according to this invention the
multiple-diagram can also comprise three or more diaphragms.
[0023] The valve 1 shown in FIG. 1 is an expansion valve for a
refrigeration system. It comprises a housing 2 with three nozzles,
namely a nozzle 3 for the incoming liquid coolant, a nozzle 4 for
the outgoing coolant, a nozzle 5 for connection to a sensor line
and a spindle 6. One end of the housing 2 is closed by a working
element 9; the working element comprises the base ring 10, the
diaphragm chamber 11 and a cover plate 12. The diaphragm chamber is
connected by way of a capillary tube 13 to a sensor 14.
[0024] FIG. 2 shows the working element 9 with the base ring 10,
diaphragm chamber 11, a cover plate 12 with a connecting passage
13a for connecting the capillary tube (not shown), a plate 18, a
bolt 19 and the multiple-diaphragm 15. In this embodiment the
multiple-diaphragm comprises two individual diaphragms.
[0025] The double diaphragm 15 is therefore pressurised from above
by the pressure owing to evaporation of the fluid in the sensor 14
and is pressured from below by the pressure of the refrigerant,
which is detected at the nozzle 5, and by a spring, not
illustrated.
[0026] FIG. 3 shows an exploded view of the working element 9 with
the base ring 10, a cover plate 12, a plate 18, a bolt 19 and the
multiple-diaphragm comprising in this embodiment a first diaphragm
16 and a second diaphragm 17.
[0027] A diaphragm is typically made of stainless steel. The
individual diaphragms in the multiple-diaphragm typically are
0.08-0.20 mm thick. The multiple-diaphragm with two 0.08 mm thick
individual diaphragms has the same stiffness as a 0.1 mm thick
single diaphragm.
[0028] In the above embodiment two identical individual diaphragms
is used. However it is also possible to use two or more diaphragms
that are slightly different and fit better together. This could be
done by forming the individual diaphragms at the same time using
the same tool, so the waves in the individual diaphragms fit
exactly. This will reduce the forces acting between the individual
diaphragms and reduce the risk of tear.
* * * * *