Valve assembly structure for a fluid system

A valve assembly structure including a valve body having a fluid passage therein to allow fluid to flow from one end port opening to an opposite end port opening, the valve body including an annular sealing surface cooperative with at least one of the end port openings with a valve stem cooperatively aligned with such end port opening to open and close the same, the valve stem having a collar restrainedly fastened to such valve stem to present an annular collar sealing surface facingly cooperative with the annular sealing surface on the valve body to fluid seal the end port opening when the valve stem is moved to a closed position.

BACKGROUND OF THE INVENTION 
The present invention relates to a unique valve assembly structure and more 
particularly to a valve assembly structure for electrically actuated 
expansion valves for refrigeration systems in which there is constant 
incremental flow rate control. 
Electrically actuated expansion valves for controlling fluid flow in 
refrigerant systems are generally well known in the refrigeration art, 
attention being directed to tho motor actuated expansion valve disclosed 
in U.S. Pat. No. 4,986,085, issued to James C. Tischer on Jan. 22, 1991 
and to the solenoid actuated expansion valve disclosed in U.S. Pat. No. 
5,120,018, issued to John D. Lamb on Jun. 9, 1992. These and other past 
fluid control valves, particularly those employed as expansion valves in 
fluid refrigeration systems, have presented flow control problems 
involving comparatively high friction seating with accompanying stem 
sticking, undesirable energy utilization, and frequent wear and 
replacement. Furthermore, inaccurate shut-off due to valve stem sticking, 
and high friction wear, as well as limited usage over large temperature 
ranges, have led to undesirable fluid leakages in many of the previous 
refrigerant systems with undesirable damages to other parts in the 
refrigerant systems--often necessitating frequent and costly parts 
replacement. 
The present invention recognizing the limitations of past valve assembly 
structures, provides a unique valve assembly structure which, although it 
has novel features readily usable with valve stems in a number of fluid 
control environments, is particularly usable with expansion valves for 
bi-flow heat pumps. The straightforward and economical valve structure of 
the present invention minimizes fluid leakage, reduces energy consuming 
torque and other energy requirements by providing low friction contact 
valve seating with minimal valve seat wear. At the same time, the novel 
structure of the present invention assures full closure of the valve stem 
with an optimum sealing surface and without undesirable valve sticking. 
The present invention further provides valve stem operation over a broad 
temperature range with minimal expansion--contraction and without 
undesirable longitudinal movement or rotation of the unique, 
straightforward, yet critical valve stem parts included in the unique 
valve structure assembly. 
Various other features of the present invention will become obvious to one 
skilled in the art upon reading the disclosure set forth herein. 
BRIEF SUMMARY OF THE INVENTION 
More particularly the present invention provides a valve assembly valve 
structure for a fluid stream comprising: a valve body including a 
flow-through fluid passage extending therein to allow a fluid stream to 
flow from one end port opening of the passage to the other end port 
opening of the passage, at least one end port opening having an annular 
sealing surface in the valve body cooperative with such end port opening 
to extend in a spaced plane surrounding the fluid passage adjacent such 
end port opening; a longitudinally extending, lineal movable, valve stem 
cooperatively mounted in the valve body, such valve stem having one end 
portion thereof geometrically sized and configured to movably cooperate 
with the annular sealing surface and the cooperative end port opening in 
the valve body to control passage of fluid through such end port opening; 
and, an annular collar member surroundingly engaging with the periphery of 
the valve stem in selected spaced relation from the extremity of the end 
portion of the valve stem adapted to cooperate with such end port opening 
to control fluid flow therethrough, the collar member including an annular 
sealing surface at one end extremity thereof adapted to engage in facing 
sealing relation with the annular sealing surface in the valve body 
cooperative with the end port opening upon lineal movement of the valve 
stem to a preselected control position. In addition the present invention 
provides valve structure wherein there is minimal, effective, sealing 
contact between engaging, facing sealing surfaces, this minimal contact 
serving to reduce energy consuming frictional contact. 
It is to be understood that various changes can be made by one skilled in 
the art in one or more of the several parts of the inventive valve 
structure disclosed herein without departing from the scope or spirit of 
the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring to FIG. 1 of the drawings, the novel valve assembly structure 2 
is disclosed as including a valve body 3 which can be formed from any one 
of a number of suitable, hard, noncorrosive materials and advantageously 
is formed as a single machined brass unit, as can be seen in FIG. 2 of the 
drawings. Valve body 3 includes a flow-through fluid passage 4 extending 
therein to allow a fluid stream to flow between one end port opening 6 
cooperative with passage 4 and the other end port opening 7 cooperative 
with 4. In the embodiment of the valve body disclosed, the fluid passage 4 
is shown as including a right angle turn with the flow axis through ports 
6 and 7 respectively being at relative right angles to each other. It, of 
course, is to be understood that other forms and shapes of valve bodies 
and fluid passage arrangements also can be utilized which incorporate the 
inventive valve assembly features disclosed herein and that fluid can flow 
from ports 6 to 7 or ports 7 to 6. 
Referring to the disclosures of FIG. 1 and 2, a portion of valve body 3 
that communicates with the fluid passage 4 and end port opening 6 is 
representively disclosed. In these FIGS. 1 and 2, it can be seen that an 
annular sealing surface 8 adjacent fluid passage 4 is provided in valve 
body 3. The annular sealing surface 8 cooperates with end port opening 6, 
extending in a spaced plane surrounding fluid passage 4. A longitudinally 
extending, lineally movable valve stem 9 is disposed in valve body 3 with 
a lower end portion 11 of such moveable valve stem 9 being geometrically 
sized, configured and aligned to moveably cooperate with annular sealing 
surface 8 and the port end opening 6 to control passage of fluid in fluid 
passage 4. The upper end portion 12 of valve stem 9, as can be seen in 
FIG. 3, is externally threaded, and, as can be seen in FIG. 1, this 
externally threaded upper end portion 12 threadedly engages with an 
internally threaded passage provided in vertical extension arm 13 of valve 
body 3 aligned with and opposite the end port opening 6. 
Still referring to FIG. 1 of the drawings, it can be seen that the 
externally threaded upper end portion 12 of valve stem 9 extends beyond 
extension arm 13 of valve body 3 to receive and have fastened to the end 
extremity thereof annular end collar or hub 14. The outer periphery of end 
collar or hub 14, in turn, is fastened to the inner wall of annular 
magnetic rotor 16 disposed to rotate within a step wired annular stator 17 
of an electric step motor assembly 18. When step motor 18 is energized, 
rotor 16 is caused to rotate and this, in turn, through hub 14 rotates 
threaded valve stem 9, which moves lineally along its longitudinal axis 
due to the threaded engagement with extension arm 13 as aforedescribed. 
Advantageously, electric step motor 18 has an operating capability of 
approximately sixty (60) steps per second and causes threaded valve stem 9 
to lineal travel approximately one fourth (1/4) of an inch from fully open 
to fully closed valve positions in approximately six (6) seconds of 
electric motor 18 operation. It is to be understood that power can be 
supplied to rotor 16 of step motor 18 through a suitable glass to metal 
fused hermetic terminal assembly (not shown) which passes appropriately 
through outer assembly housing 24 (FIG. 1). It further is to be understood 
that the present invention is not to be considered as limited to the 
specific operating capability as set forth herein, but that other types of 
stepper ranges could be utilized. In addition other coupling structures 
could be utilized to connect the valve stem to the motor without departing 
from the scope of the present invention. 
As again can be particularly seen in the disclosure of FIG. 2 and, in 
accordance with certain of the features of the present invention, the 
lower end portion 11 of valve stem 9 can be provided with a plurality of 
longitudinally extending, spaced barb-like protrusions 19 which extend 
radially outward from the periphery of valve stem 9. In addition valve 
stem 9 is provided with an annular step 21, thus providing a collar 
receiving recess, the step 21 and barbs 19 serving to restrain 
longitudinal and rotational movement respectively of an annular collar 22, 
which annular collar 22 is press fit into valve stem 9 in the step formed 
recess of valve stem 9 with one extremity of annular collar 22 abutting 
the annular step 21 in the valve stem 9 and with the inner wall of annular 
collar 22 engaging with the spaced barbs 19 on the valve stem. 
Advantageously, annular collar 22 can be formed from a suitable low 
friction, long wearing material, such as an elastomeric material sold 
under the trademark "RULON". It is to be understood that the polymeric 
material selected desirably should be wear resistant, should provide a 
smooth surface with minimal frictional contact, and should be capable of 
operation over a broad temperature range. In accordance with one feature 
of the present invention annular collar 22 is of carefully selected 
thickness and length in accordance with the size of the valve stem with 
which it engages so as to minimize possible buckling of the collar on the 
stem with which it engages. In accordance with still another feature of 
the present invention, the lower peripheral end portion of annular collar 
22 advantageously is tapered inwardly at an angle range between 
approximately fifteen (15) to sixty (60) degrees and preferably 
aproximately sixty (60) degrees measured from the narrow width annular 
sealing surface extremity 23 of collar 22 which faces the annular sealing 
surface 8 of valve body 3. This selected inwardly sloping angle serves to 
selectively minimize frictional contact between the facing sealing 
surfaces upon engagement when the valve stem 9 has been moved to "closed" 
position relative end port opening 6, as can be seen in FIG. 1. It is to 
be understood that the greater the angle the lesser fluid restriction 
would occur between spaced port openings 6 and 7 and it further is to be 
understood that to provide such minimal contact surfaces, it also would be 
possible to provide a raised and appropriately angled annular sealing 
surface 8 and to even provide a recess in valve body 3 to receive a 
separate annular sealing surface ring which could include an inwardly 
tapered contact surface. It also is to be noted that a cup-shaped housing 
shell 24 (FIG. 1) is provided to engage with valve body 3 to protect the 
electric step motor assembly 18. 
Referring to FIG. 4, a refrigeration system in the form of a heat pump is 
disclosed which system can incorporate the aforedescribed valve assembly 
structure in the form of a reversing flow expansion valve 26. The 
expansion valve 26 can be positioned, as is known in the art, between an 
indoor refrigerant-to-air-heat exchange coil 27 and an outdoor 
refrigerant-to-air-heat exchange coil 28 with the two coils 27 and 28, in 
turn, being connected through a 4-way reversing control valve 29 for 
compressor 31.