Pressurized and sealing device and a process for hermetic systems

Patent of invention for pressurizing and sealing device and process for hermetic systems, provided with a gas feeding conduit (1), comprising: a tubular body (10) defining an internal chamber (13) between a first end (11) which can be tightly seated against an open external end (2) of the gas feeding conduit (1) and a second open end (12), and a pressurized gas inlet nozzle (14) opened into the internal chamber (13); an elastomeric plug (30) which can be positioned inside the tubular body (10) in such a way that it can be selectively displaced from a pressurizing condition, sealing the second end (12) of the tubular body (10) when the internal chamber (13) and the hermetic system are pressurized through the pressurized gas inlet nozzle (14), to a plugging condition, in which it is sealingly fitted and maintained in the external end (2) of the gas feeding conduit (1) after said pressurization has ended; and an impelling means (40), which is coupled to the tubular body (10) and which can be selectively activated through the second end (12) of said body so as to conduct the elastomeric plug (30) from the pressurizing condition to the plugging condition.

TECHNICAL FIELD 
The present invention refers to a pressurizing and sealing device and 
process for hermetic systems, particularly used for supplying gases to 
hermetic compressors for cooling systems of the type used in 
refrigerators, freezers and air-conditioners, for example. 
BACKGROUND OF THE INVENTION 
The hermetic compressors for these cooling systems have their shells 
defining a hermetic chamber to be pressurized by an inert gas, such as 
nitrogen, and plugged in such a way as to prevent humidity from entering 
and consequently rusting the components located inside the hermetic 
chamber during the transport and warehousing of these compressors. Said 
pressurization is carried out through a gas feeding conduit, generally of 
a short length, attached to the hermetic shell so as to allow fluid 
communication between the interior and exterior of the chamber. 
Before the inert gas is introduced into the interior of the hermetic shell, 
an open and of the gas feeding conduit is sealingly closed with an 
elastomeric element in the form of a plug, which is fitted under pressure 
and which is later perforated with a reduced diameter needle used to 
inject gas through the gas feeding conduit. 
Although the needles have a small diameter, after they are removed at the 
end of the pressurizing operation of the shell, the plug remains with its 
structure broken, allowing the occurrence of small leaks of the gas 
introduced into the shell (close to 50 PPM). Besides this deficiency, this 
process of introducing gas into hermetic systems has the disadvantage of 
being a manual process, thus slow and subject to error. 
DISCLOSURE OF THE INVENTION 
Thus, it is an object of the present invention to provide a pressurizing 
and sealing device and process for hermetic systems, such as the hermetic 
shell of a cooling system compressor, which eliminates the occurrence of 
leaks which exist in the current technique and which will allow the 
automation of gas feeding in such systems. 
This and other objectives are attained by means of a pressurizing and 
sealing device for hermetic systems, which is provided with a gas feeding 
conduit having an open external end comprising: a tubular body defining an 
internal chamber between a first end which can be tightly seated against 
the external end of the gas feeding conduit, and a second open end and a 
pressurized gas inlet nozzle which opens into the internal chamber; an 
elastomeric plug which can be positioned inside the tubular body in such a 
way as to be selectively displaceable from a pressurizing condition, 
sealingly closing the second end of the tubular body when the internal 
chamber and hermetic system are pressurized through the pressurized gas 
inlet nozzle, to a plugging condition in which it is sealingly fitted and 
retained in the external end of the gas feeding conduit after said 
pressurization has ended; and an impelling means which is coupled to the 
tubular body and which can be selectively activated through the second end 
of said body, so as to conduct the elastomeric plug from the pressurizing 
condition to the plugging condition. 
According to the present invention, the pressurizing and sealing process 
comprises the steps of: a--tightly seating the first end of a tubular body 
against the open external end of the gas feeding conduit; b--closing a 
second end of the tubular body with an elastomeric plug; c--pressurizing 
an internal chamber, defined between the first and second ends of the 
tubular body; d--selectively displacing the elastomeric plug from the 
pressurizing condition, in which it closes the second end of the tubular 
body, to a plugging condition, in which it is sealingly fitted and 
retained in the open external end of the gas feeding conduit after the 
pressurization of said internal chamber has ended; and e--separating the 
first end of the tubular body from the tight seating condition at the end 
of the gas feeding conduit. 
As it can be observed, the invention permits obtaining mechanical 
pressurizing and plugging conditions for said hermetic systems, without 
modifying or altering the original hermetic structure of the elastomeric 
plugs with the use of gas injection needles.

BEST MODE FOR CARRYING OUT THE INVENTION 
The pressurizing and sealing device and process for hermetic systems of the 
present invention will be described regarding the introduction of a 
specific volume of inert gas into a hermetic shell of a cooling system 
compressor, to prevent humidity from entering into said hermetic shell. 
The feeding of the inert gas into the hermetic shell occurs by introducing 
the gas through the low pressure side of the system to which said chamber 
is connected normally through a gas feeding conduit 1, which is a 
derivation of a gas circulation pipeline of said system, or still directly 
into the hermetic chamber. 
According to the figures presented, the pressurizing and sealing device of 
the present invention comprises a cylindrical tubular body 10 having a 
first end, which is open and which can be tightly seated on an open 
external end 2 of the gas feeding conduit 1, and at least a second end 12 
opposite to the first end 11, axially aligned to it such that, when said 
tubular body 10 is mounted to the gas feeding conduit 1, said first and 
second ends 11 and 12 are axially aligned with the external end 2 of the 
gas feeding conduit 1. The tight seating of the tubular body 10 to the 
external end 2 is obtained through the elastic deformation of at least 
part of an annular seal 20, positioned around said external end 2 and 
which squeezes the latter when the first end 11 of the tubular body 10 is 
seated thereon. The positioning of the annular seal 20 around the external 
end 2 occurs in such a way that an end portion of said annular seal 20 
remains projecting itself beyond said external end 2 and against which is 
seated the first end 11 of the tubular body 10. This condition of elastic 
deformation of the annular seal 20 by the tubular body 10 defines an 
operational position for the latter. The elastic deformation leads the 
annular seal 20 to an operational condition of compressing the external 
end 2 of the feeding conduit 1. During the elastic deformation, the end 
portion of the annular seal 20, against which is seated the first end 11 
of the tubular body, radially compresses the external end 2 while being 
axially projected towards a lowered portion, in the shape of a wedge for 
example, of said first end 11 of the tubular body 10, compressively 
surrounding said external end 2 and sealing the contact between the 
interior of an internal chamber 13 defined between the first and second 
ends 11 and 12 of the tubular body 10 and the exterior of the device in 
question. 
After the tubular body 10 has been seated onto the external end 2, an 
elastomeric plug 30 is positioned inside said tubular body 10 adjacent to 
the second end 12 of said body, so as to be selectively displaced from a 
pressurizing condition, sealingly closing said second end 12 into a 
plugging condition in which it is sealingly fitted and retained in the 
external end 2 of the gas feeding conduit 1. The displacement of the 
elastomeric plug 30 to the plugging condition is obtained by means of an 
impelling means 40 coupled to the tubular body 10 and selectively 
activated through its second end 12, said impelling means 40 being, for 
example, an insertion rod provided through the second end 12 of the 
tubular body 10 and which carries, in an internal end 41 located in the 
inside of the tubular body 10, a pin 42 to which is coupled the 
elastomeric plug 30. This coupling occurs by fitting the pin 42 into a 
tubular base portion 31 of the elastomeric plug 30 facing the second end 
12 of the tubular body 10. This fitting occurs, for example, before 
introducing the elastomeric plug into the tubular body 10 and is 
maintained until said elastomeric plug 30 reaches its plugging condition. 
Due to the construction of the elastomeric plug 30, in the plugging 
condition, its base portion 31 remains external to said external end 2. 
Although only one construction for a impelling means 40 has been described, 
others are possible, without altering the concept presented herein, such 
as said impelling means being a pressurizing element. 
According to the present invention, when the elastomeric plug 30 is in its 
pressurizing condition, gas which is to be pressurized into the feeding 
conduit 1 and consequently into the hermetic system is introduced into the 
internal chamber 13 through a pressurized gas inlet nozzle 14 provided in 
a substantially radial groove 15 which is defined at a portion of the 
lateral surface of the tubular body 10 between the first and second ends 
11, 12 of the body and opened into the internal chamber 13. 
In a preferred and illustrated constructive form, the annular seal 20 is 
carried by a positioning element 50 which leads said annular seal 20 to 
the position around the external end 2. Although not shown, said annular 
seal 20 can be carried by the tubular body 10 itself, which would position 
it around the external end 2 before provoking the elastic deformation of 
said seal previously described. 
In the construction illustrated, the positioning element 50 is selectively 
displaced between an inoperative position, in which the annular seal 20 is 
separated from the external end 2 of the feeding conduit 1, and an 
operative position for positioning said annular seal 20 around the 
external end 2 obtained prior to the displacement of the tubular body 10 
from an inoperative position, in which its first end 11 is separated from 
the annular seal 20 which is already positioned around said external end 
2, to the operative position, elastically deforming the annular seal 20. 
The operative position of the tubular body 10 is maintained by a 
compressing element 60, which is provided between the second end 12 of the 
tubular body 10 and the positioning element 50 and which acts against said 
tubular body 10. The inoperative position of the latter is maintained by 
its action against the compressing element 60 which in this construction 
is a helicoidal spring. 
According to the present invention, the positioning element 50 defines an 
external guide which displaces the tubular body 10 between its inoperative 
and operative positions and takes the form of, for example, a continuous 
tubular cover 51 which internally houses the compressing element 60 
adjacent to an annular bottom wall portion 52. The placement of the 
insertion rod 40 inside the tubular body 10 occurs through this annular 
bottom wall portion 52. 
In the construction illustrated, the tubular cover 51 carries a mandrel 
element 53, which is threadably affixed to a fastening end of the tubular 
cover 51 opposite to the annular bottom wall portion 52 and adjacent to 
the first end 11 of the tubular body 10. The annular seal 20 is located 
inside the mandrel element 53, adjacent to one of its ends which fits into 
the external end 2 when the tubular cover 51 is mounted to the latter. For 
this mounting to occur, the tubular body 10 is led to its inoperative 
position, when its first end 11 is maintained separated from the fixation 
end of the tubular cover 51 by means of a lever 54 coupled to the tubular 
body 10 and which is projected beyond said tubular cover 51. The lever 54 
also leads said tubular body 10 into its operative position, preferably 
retaining it in each of its said inoperative and operative positions. 
In the construction illustrated, the tubular cover 51 has lateral openings 
55, said openings being defined so as to allow the respective mounting of 
the pressurized gas inlet nozzle 14 and the lever 54 onto the tubular body 
10. In a constructive option, the lateral opening 55 defines a stop for 
the lever 54, limiting the displacement of the tubular body 10 between its 
inoperative and operative positions. 
Although only one construction of a tubular body 10 has been illustrated, 
other constructions are possible, such as a tubular body of a shape other 
than cylindrical, having a plurality of ends interconnected by the 
internal chamber and having at least one gas feeding nozzle with a 
respective end opened to said internal chamber, with each said nozzle 
being in the form of a conduit. 
The mounting of the pressurizing and sealing device of the present 
invention occurs according to a process generically including the 
following steps: tightly seating the first end 11 of the tubular body 10 
against the open end 2 of the gas feeding conduit; closing the second end 
12 of the tubular body 10 with the elastomeric plug 30; pressurizing the 
internal chamber 13 of the tubular body 10; selectively displacing the 
elastomeric plug 30, from the closing condition of the second end 12 of 
the tubular body 10 to the plugging condition at the external end 2 of the 
gas feeding conduit 1, after the pressurization of the gas in the gas 
feeding conduit 1 has ended; and separating the first end 11 of the 
tubular body 10, preventing it from being tightly seated onto the external 
end 2 of the gas feeding conduit 1. The steps previous to the one of 
pressurizing the internal chamber 13 can occur according to a different 
sequence than the one presented, without altering the result intended. The 
process being described also includes, previous to the first step cited, 
the following steps: positioning the annular seal 20 around the external 
end 2 of the gas feeding conduit 1; and displacing the tubular body 10 
from its inoperative position to its operative position.