CA1069839A - Refrigeration compressor breakoff tube - Google Patents
Refrigeration compressor breakoff tubeInfo
- Publication number
- CA1069839A CA1069839A CA276,307A CA276307A CA1069839A CA 1069839 A CA1069839 A CA 1069839A CA 276307 A CA276307 A CA 276307A CA 1069839 A CA1069839 A CA 1069839A
- Authority
- CA
- Canada
- Prior art keywords
- tube
- breakoff
- tip
- transition region
- attachment
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Compressor (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A breakoff tube formable by deep drawing without the need for a separate machining operation.
between an attachment portion adapted for connection to a compressor casing and a closed tip portion there is an annular transition region having a wall thickness in the attachment and tip portions. The inside and outside diameters of the tip portion are smaller than the inside and outside diameters, respectively, of the attachment portion.
A breakoff tube formable by deep drawing without the need for a separate machining operation.
between an attachment portion adapted for connection to a compressor casing and a closed tip portion there is an annular transition region having a wall thickness in the attachment and tip portions. The inside and outside diameters of the tip portion are smaller than the inside and outside diameters, respectively, of the attachment portion.
Description
~9~339 The present inven-tion relates generall~ to hermetically sealed refrigeration comprssors and more particularly to an improved breakoff tube for effecting temporary sealing of the compressor outer casing and permitting later connection to a line such as the suction line of a re~rigeration system.
In the manufacture of refrigerators and air conditioners, hermetically sealed compressors are generally manufactured as complete units separate from the rest of the refrigeration system and then temporarily stored until later connection into the refrigeration system. In order to prevent contamination during the storage period, i~ is a generally accepted manufacturing practice to either evacuate the compressors or to fill the compressors with dry air or other preserving gas and then to hermetically seal them. Upon later connection into the refrigeration system, temporary seals are broken and fluid connections are made. `
One device which is frequently used to effect ;~
a temporary hermetic seal and yet permit later connection to the suction line of a refrigeration system is a breakoff tube. A breakoff tube generally comprises a tubular member which is open on one end and closed on the other. The open end is partially inserted through an aperture provided for this purpose in the outer casing of the compressor and then welded or brazed in place to complete a hermetic seal. A separate connection, preferably equipped with a valve, is used to evacuate the compressor casing or to inject a preserving gas, as desired.
In order to facilitate later connection to the suction line, the breakoff tube is constructed so that the tip thereof may be readily broken off through the use of a ~
- 1 - .
.~ ~ . .. . .
- ~
~691~9 suitable tool. After the tip is broken of~, the breakof tube and the open end of the suction line are sealingly joined by partial insertion of one into the other followed by brazing or silver soldering.
One type of prior art breakoff tube is manufactured in two operations. The basic tube is formed from a sheet stock blank into a relatively long, small diameter tube by the process known as deep drawing. The resulting basic tube is open on end end, closed on khe other end, and has a substantially constant diameter. The material used is generally copper plated steel. To facilitate the breaking off of the tip or end portion of the breakoff tube, a circumferentially disposed V-shaped notch is formed by a machining operation. The notch produces a weakened portion where the tip portion of the breakoff tube can be separated. Ideally, the depth of the notch is carefully controlled so that the breakoff tube is capable of withstanding stresses and impacts resulting from normal handling, yet is sufficiently weakened to permit easy breakoff when desired. Breakoff may be accomplished through the use of a tool comprising a cylindrical cavity for receiving the end of the breakoff tube and having a sufficient length so that enough force can be produced by leverage to break off the tip portionO
Such a breakoff tube suffers the disadvantage of requiring a separate machinig operation (and equipment) to form the circumferential notch. An additional disadvantage is difficulty in attaining uniformity between successively ~` manufactured breakoff tubes due both to tolerances in the manufacturing of the basic tube, prior to machining of khe circumferential notch, and to machining variables, such as tool wear, tool positioning, and part alignment, to name . . ' :
.
~0~;~839 a few. variations in ~he ~iameter of the breako~f tube or the wall thickness can resul~ i~ disporportionate variations in the thickness o~ m~terial remaining after the notch is cut. AS a result, some tubes may bxeak off too easily while others are difficult to break off or do not break off cleanlyl Furthermore, some are even broken off during the machining operation, and thus immediately become scrap.
ccordingly, it is an object of the invention to provide a breakoff tube which is easy and inexpensive to manufacture and which can be manufactured with a high degree of uniformity between successively manufactured breakoff tubes.
In accordance with the invention, a breakoff tube is provided which is formable from a sheet stock blank by deep drawing. The breakoff tube includes a tubular attachment portion having an open end adapted for connection to the compressor casing by conventional methods. The breakoff tube further includes a tubular tip portion having inside and outside diameters which are smaller than the inside and outside diamters, respectively, of the attachment portion. The distal end of the tip portion is closed. Between the attachment and tip portion is an annular transition region having a wall thickness which is substantially less than the wall thickness in the attachment and tip portions. The breakoff tube is in a complete form immediately after completion of .:
the deep drawing operation and is ready for assembly to the compressor casiny without the need for a separate machining operation.
While the novel features of the invention are set forth with particularity in the appended claims, the 3~3 invention, both as to organi~ation and content, will be better understood and appreciated, along with other objects and features thereof from the following detailed description taken in conjunction with the drawings, in which:
Figure l is an overall perspective view of a compressor outer casing including a breakoff tube according to the present invention.
Figure 2 is a greatly enlarged side elevational view, partly in cross section, of a prior art breakoff tube.
Figure 3 is a greatly enlarged side elevational view, partly in cross section, o~ the breakoff tube shown in Figure 1.
Referring first to Figure l, there is shown a generally cylindrical outer casing lO of a hermetically sealed refrigeration compressor unit. A conventional compressor (not shown) is disposed within the casing lO.
Attached to the side of the casing 10 and communicating through an aperture to the interior thereof is a breakoff tube 12, constructed according to the present invention. As discussed above, the breakoff tube 12 provides a temporary hermetic seal and yet facilitates later fluid connection to a line such as the suction line forming a part of a closed circult refrigeration system. The compressor unit also includes a discharge line and electrical power leads (not shown) passing from within the casing 10 through suitable openings.
Leaving Figure 1 for the moment and referring to Figure 2, a greatly enlaxged cross sectional view of a prior art breakoff tube 14 is shown. The prior art breakoff tube 14 is open at one end (not shown) and adapted for connection to the compressor casing by welding or brazing. The basic tube of the breakoff tube 14 is ~ormed . ~ ~
!339 from a sheet s tock blank by the metal forming process known as deep drawing. As is well known in the art o metal forming, deep drawing is a metal ~orming process whereby a flat sheet is orced into a cylindrical ~emal die by a male die plunger and co~formed to the shape of the male die plunger. The forming of a relatively long, small diameter tube by deep drawing normally requires several successive draws. After the basic tube has been formed, a circumferential V-shaped notch 16 is machined into the tube 14, defining a tip portion 18 and an attach-ment portion 20 separated by a weakened portion comprising material left radially inside the notch 16. The tip portion 18 can then be broken off when desired by the use o a suitable tool. It will be apparent that the forming of the notch 16 requires an additional operation in the process of manufacturing the prior art breakoff tube 14 and a suitable machine to accomplish it.
Referring now to Figure 3, and again to Figure l, the breakoff tube 12 embodying the present invention will now be described in greater detail. The breakoff tube 12 is of a configuration which is formable from a sheet stock blank by deep drawing and which has a weakened portion built in and formed during the drawing operation. The configuration thus is immediately usable as a breakoff tube without the necessity for a separate machining operation. The breakoff tube 12 comprises a tubular attachment portion 22 having an open end 24 adapted for connection to the compressor casing lO by conventional welding or brazing. The breakoff tube 12 further comprises a tubular tip portion 28 having inside and outside diameters which are smaller than the inside and outside diameters, respectively, of the attachment portion 22. The distal 3~
end 30 of the tip portion 28 has a generalIy semi-spherical configuration and is closed. Due to ~he di~ferent diameters of the attachment portion 22 and the tip portion 28, there i5 defined therebetween an annular transition region 32.
The transition region 32 is similar to a conventional pinch trim, carried all the way through the material, which is often used as a final step in drawing operations to trim a part from the remaining part of the blank. The transition region 32 is, in essence, a partial pinch, and as such is readily formable during the drawing operation. The partial pinch, of course, eliminates the need for the additional machining operation to form the notch 16 (Figure 2).
The wall thickness T in the transition region 32 is substantially less than the wall thicknesses WA and WT in the attachment and tip portions 22 and 28, respectively.
Preferably, the wall thicknesses WA and WT of the attachment portion 22 and the end portion 2~ are approximately the same and the thickness T in the transition region 32 is approximately 1/4 to 1/5 as much. The length L of the transition region 32iis approximately the same as the transition region wall thickness T. To facilitate the deep drawing operation, a definite transitional radius R is permitted, rather than a sharp right-angled transition.
In a preferred embodiment of the invention, dimensions are as follows:
Attachment portion 22:
Inside diameter .255 inch Outside diameter .312 inch Wall thickness WA 035 inch .
, ~;g~3~
Tip portion 28:
Inside diameter .210 inch Outside diameter .277 inch Wall thickness wT .025 inch Transition region 32-Length L .010 ~ ~005 inch Thickness T . 011 + . 003 inch Transitional radius R . 030 + . 010 inch A similar principle could be applied to tubing sections instead of drawn tubes. A short length of tubing could be deformed by swaging down the diameter of one pad ~
and die pinching a transition section, similar to the ~ ~-transition region 32 described above. This would be done in a progressive die type of operation. In contrast to the breakoff tube 12 formed by deep drawing, an additional operation to pinch and seal one end of the tube shut -would be required.
It will be apparent, therefore, that the present ~-invention provides an improved breakoff tube formable from a sheet stock blank by deep drawing without additional ~ -machining operations and which may be manufactured with substantial uniformity between successively manufactured pieces. ;~
While a specific embodiment of the invention has been illustrated and described herein, it is realized that numerous modifications and changes will occure to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spiri.t and scope of the invention.
.
. .
.
In the manufacture of refrigerators and air conditioners, hermetically sealed compressors are generally manufactured as complete units separate from the rest of the refrigeration system and then temporarily stored until later connection into the refrigeration system. In order to prevent contamination during the storage period, i~ is a generally accepted manufacturing practice to either evacuate the compressors or to fill the compressors with dry air or other preserving gas and then to hermetically seal them. Upon later connection into the refrigeration system, temporary seals are broken and fluid connections are made. `
One device which is frequently used to effect ;~
a temporary hermetic seal and yet permit later connection to the suction line of a refrigeration system is a breakoff tube. A breakoff tube generally comprises a tubular member which is open on one end and closed on the other. The open end is partially inserted through an aperture provided for this purpose in the outer casing of the compressor and then welded or brazed in place to complete a hermetic seal. A separate connection, preferably equipped with a valve, is used to evacuate the compressor casing or to inject a preserving gas, as desired.
In order to facilitate later connection to the suction line, the breakoff tube is constructed so that the tip thereof may be readily broken off through the use of a ~
- 1 - .
.~ ~ . .. . .
- ~
~691~9 suitable tool. After the tip is broken of~, the breakof tube and the open end of the suction line are sealingly joined by partial insertion of one into the other followed by brazing or silver soldering.
One type of prior art breakoff tube is manufactured in two operations. The basic tube is formed from a sheet stock blank into a relatively long, small diameter tube by the process known as deep drawing. The resulting basic tube is open on end end, closed on khe other end, and has a substantially constant diameter. The material used is generally copper plated steel. To facilitate the breaking off of the tip or end portion of the breakoff tube, a circumferentially disposed V-shaped notch is formed by a machining operation. The notch produces a weakened portion where the tip portion of the breakoff tube can be separated. Ideally, the depth of the notch is carefully controlled so that the breakoff tube is capable of withstanding stresses and impacts resulting from normal handling, yet is sufficiently weakened to permit easy breakoff when desired. Breakoff may be accomplished through the use of a tool comprising a cylindrical cavity for receiving the end of the breakoff tube and having a sufficient length so that enough force can be produced by leverage to break off the tip portionO
Such a breakoff tube suffers the disadvantage of requiring a separate machinig operation (and equipment) to form the circumferential notch. An additional disadvantage is difficulty in attaining uniformity between successively ~` manufactured breakoff tubes due both to tolerances in the manufacturing of the basic tube, prior to machining of khe circumferential notch, and to machining variables, such as tool wear, tool positioning, and part alignment, to name . . ' :
.
~0~;~839 a few. variations in ~he ~iameter of the breako~f tube or the wall thickness can resul~ i~ disporportionate variations in the thickness o~ m~terial remaining after the notch is cut. AS a result, some tubes may bxeak off too easily while others are difficult to break off or do not break off cleanlyl Furthermore, some are even broken off during the machining operation, and thus immediately become scrap.
ccordingly, it is an object of the invention to provide a breakoff tube which is easy and inexpensive to manufacture and which can be manufactured with a high degree of uniformity between successively manufactured breakoff tubes.
In accordance with the invention, a breakoff tube is provided which is formable from a sheet stock blank by deep drawing. The breakoff tube includes a tubular attachment portion having an open end adapted for connection to the compressor casing by conventional methods. The breakoff tube further includes a tubular tip portion having inside and outside diameters which are smaller than the inside and outside diamters, respectively, of the attachment portion. The distal end of the tip portion is closed. Between the attachment and tip portion is an annular transition region having a wall thickness which is substantially less than the wall thickness in the attachment and tip portions. The breakoff tube is in a complete form immediately after completion of .:
the deep drawing operation and is ready for assembly to the compressor casiny without the need for a separate machining operation.
While the novel features of the invention are set forth with particularity in the appended claims, the 3~3 invention, both as to organi~ation and content, will be better understood and appreciated, along with other objects and features thereof from the following detailed description taken in conjunction with the drawings, in which:
Figure l is an overall perspective view of a compressor outer casing including a breakoff tube according to the present invention.
Figure 2 is a greatly enlarged side elevational view, partly in cross section, of a prior art breakoff tube.
Figure 3 is a greatly enlarged side elevational view, partly in cross section, o~ the breakoff tube shown in Figure 1.
Referring first to Figure l, there is shown a generally cylindrical outer casing lO of a hermetically sealed refrigeration compressor unit. A conventional compressor (not shown) is disposed within the casing lO.
Attached to the side of the casing 10 and communicating through an aperture to the interior thereof is a breakoff tube 12, constructed according to the present invention. As discussed above, the breakoff tube 12 provides a temporary hermetic seal and yet facilitates later fluid connection to a line such as the suction line forming a part of a closed circult refrigeration system. The compressor unit also includes a discharge line and electrical power leads (not shown) passing from within the casing 10 through suitable openings.
Leaving Figure 1 for the moment and referring to Figure 2, a greatly enlaxged cross sectional view of a prior art breakoff tube 14 is shown. The prior art breakoff tube 14 is open at one end (not shown) and adapted for connection to the compressor casing by welding or brazing. The basic tube of the breakoff tube 14 is ~ormed . ~ ~
!339 from a sheet s tock blank by the metal forming process known as deep drawing. As is well known in the art o metal forming, deep drawing is a metal ~orming process whereby a flat sheet is orced into a cylindrical ~emal die by a male die plunger and co~formed to the shape of the male die plunger. The forming of a relatively long, small diameter tube by deep drawing normally requires several successive draws. After the basic tube has been formed, a circumferential V-shaped notch 16 is machined into the tube 14, defining a tip portion 18 and an attach-ment portion 20 separated by a weakened portion comprising material left radially inside the notch 16. The tip portion 18 can then be broken off when desired by the use o a suitable tool. It will be apparent that the forming of the notch 16 requires an additional operation in the process of manufacturing the prior art breakoff tube 14 and a suitable machine to accomplish it.
Referring now to Figure 3, and again to Figure l, the breakoff tube 12 embodying the present invention will now be described in greater detail. The breakoff tube 12 is of a configuration which is formable from a sheet stock blank by deep drawing and which has a weakened portion built in and formed during the drawing operation. The configuration thus is immediately usable as a breakoff tube without the necessity for a separate machining operation. The breakoff tube 12 comprises a tubular attachment portion 22 having an open end 24 adapted for connection to the compressor casing lO by conventional welding or brazing. The breakoff tube 12 further comprises a tubular tip portion 28 having inside and outside diameters which are smaller than the inside and outside diameters, respectively, of the attachment portion 22. The distal 3~
end 30 of the tip portion 28 has a generalIy semi-spherical configuration and is closed. Due to ~he di~ferent diameters of the attachment portion 22 and the tip portion 28, there i5 defined therebetween an annular transition region 32.
The transition region 32 is similar to a conventional pinch trim, carried all the way through the material, which is often used as a final step in drawing operations to trim a part from the remaining part of the blank. The transition region 32 is, in essence, a partial pinch, and as such is readily formable during the drawing operation. The partial pinch, of course, eliminates the need for the additional machining operation to form the notch 16 (Figure 2).
The wall thickness T in the transition region 32 is substantially less than the wall thicknesses WA and WT in the attachment and tip portions 22 and 28, respectively.
Preferably, the wall thicknesses WA and WT of the attachment portion 22 and the end portion 2~ are approximately the same and the thickness T in the transition region 32 is approximately 1/4 to 1/5 as much. The length L of the transition region 32iis approximately the same as the transition region wall thickness T. To facilitate the deep drawing operation, a definite transitional radius R is permitted, rather than a sharp right-angled transition.
In a preferred embodiment of the invention, dimensions are as follows:
Attachment portion 22:
Inside diameter .255 inch Outside diameter .312 inch Wall thickness WA 035 inch .
, ~;g~3~
Tip portion 28:
Inside diameter .210 inch Outside diameter .277 inch Wall thickness wT .025 inch Transition region 32-Length L .010 ~ ~005 inch Thickness T . 011 + . 003 inch Transitional radius R . 030 + . 010 inch A similar principle could be applied to tubing sections instead of drawn tubes. A short length of tubing could be deformed by swaging down the diameter of one pad ~
and die pinching a transition section, similar to the ~ ~-transition region 32 described above. This would be done in a progressive die type of operation. In contrast to the breakoff tube 12 formed by deep drawing, an additional operation to pinch and seal one end of the tube shut -would be required.
It will be apparent, therefore, that the present ~-invention provides an improved breakoff tube formable from a sheet stock blank by deep drawing without additional ~ -machining operations and which may be manufactured with substantial uniformity between successively manufactured pieces. ;~
While a specific embodiment of the invention has been illustrated and described herein, it is realized that numerous modifications and changes will occure to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spiri.t and scope of the invention.
.
. .
.
Claims (2)
1. A metal breakoff tube for use on a hermetic refrigerator compressor casing and formable from a sheet stock blank by deep drawing, said breakoff tube comprising:
a tubular attachment portion having an open end adapted for connection to the compressor casing:
a tubular tip portion having inside and outside diameters which are smaller than the inside and outside diameters, respectively, of said attachment portion, the distal end of said tip portion being closed; and an annular transition region between said portions, the wall thickness in said transition region being substantially less than the tube wall thicknesses in said attachment and tip portions.
a tubular attachment portion having an open end adapted for connection to the compressor casing:
a tubular tip portion having inside and outside diameters which are smaller than the inside and outside diameters, respectively, of said attachment portion, the distal end of said tip portion being closed; and an annular transition region between said portions, the wall thickness in said transition region being substantially less than the tube wall thicknesses in said attachment and tip portions.
2. A breakoff tube according to Claim 1, wherein the thickness in said transtion region is within the range of approximately 1/5 to 1/4 of wall thickness in said attachement and tip portions.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US68213576A | 1976-04-30 | 1976-04-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1069839A true CA1069839A (en) | 1980-01-15 |
Family
ID=24738370
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA276,307A Expired CA1069839A (en) | 1976-04-30 | 1977-04-07 | Refrigeration compressor breakoff tube |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1069839A (en) |
-
1977
- 1977-04-07 CA CA276,307A patent/CA1069839A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5189790A (en) | Method of fabricating a double walled pipe elbow | |
| US5737952A (en) | Method and apparatus for producing a header with openings | |
| US5727303A (en) | Method of making a tube and fitting assembly | |
| US6581983B1 (en) | Fitting or mounting for producing a press joint with an inserted tube end | |
| US4219221A (en) | Coupling for rejoining sealed tubing | |
| US4446891A (en) | Method for repairing and/or reinforcing a pipe system, and a device for utilization of the method | |
| US4220687A (en) | Powdered metal casing for perforating charge and its method of manufacture | |
| US4338713A (en) | Method of manufacture of powdered metal casing | |
| CA1069839A (en) | Refrigeration compressor breakoff tube | |
| US2329770A (en) | Closing ends of metal tubes | |
| US4162566A (en) | Method and coupling for severing and rejoining sealed tubing | |
| US3767334A (en) | Hermetically sealed compressor assembly | |
| JPS624574B2 (en) | ||
| GB1592135A (en) | Method of introducing gas into a container | |
| US3522648A (en) | Sealed hole and method of producing | |
| US4352231A (en) | Method of forming a low pressure low cost accumulator | |
| JPH0377015B2 (en) | ||
| US5623975A (en) | Gas capsule filling and sealing process | |
| US5305942A (en) | Method for sealing thermal processing apparatus | |
| US4262942A (en) | Tube fitting assembly with shoulder means | |
| JPS59131781A (en) | Enclosed type motor-compressor | |
| US4148198A (en) | Refrigeration charging and sealing device | |
| WO1999025505A3 (en) | Method and device for reducing the wall friction during an internal high pressure forming process | |
| US4031732A (en) | Method for hydrostatic extrusion of tubes | |
| JPS6357988A (en) | Method of connecting piping and flange |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |