Valve body for oilfield applications

A valve body for use in cementing, fracturing or acidizing operations in well drilling with improved wear resistance to extend the operating life of the valve. The valve includes a hardened metal valve head having urethane legs replaceably attached to the valve head. A urethane valve insert may also be provided to facilitate sealing engagement with the valve seat. The urethane legs reduce the overall weight of the valve to reduce the mass of the pumping valve against the valve seat thereby extending the life of the valve. The valve legs are attached to the valve head through fitting engagement and can be replaced and/or repaired.

BACKGROUND OF THE INVENTION 
I. Field of the Invention 
This invention relates to a valve used in oil field pumps for cementing, 
fracturizing and acidizing operations and, in particular, to a valve 
adapted to sealing cooperate with a valve seat having a hardened alloy 
valve head with urethane legs replaceably connected to the valve head in 
order to reduce the operating mass of the valve thereby increasing 
productive life. 
II. Description of the Prior Art 
Pumps and other valving mechanisms are widely used in deep well drilling 
and production operations. The valve assemblies associated with such 
devices can be subjected to extreme stresses as the valve pumps several 
hundred strokes per minute. In addition, the pump may be used in 
cementing, fracturing or acidizing operations subjecting the valve to an 
errosive environment. To prevent frequent downtime in the production well, 
the pump, particularly the valves, must be rugged enough to withstand such 
an environment yet capable of extreme stroke rates. 
Past known valve assemblies used in oilfield application employed one or 
two piece hardened metal alloy valves which cooperated with a valve seat. 
The two-piece valve included a valve cap threadably mounted to a valve 
body having guide legs. A rubber or polyurethane insert ring is mounted 
between the cap and body to provide sealing engagement between the valve 
and the valve seat. The one-piece valve includes an integral valve cap and 
body to which the valve insert is mounted. Although these valves can be 
removed to replace the sealing insert or the entire valve, such downtime 
can be costly and is therefore preferably minimized. 
The striking shock of the past known valves results in failure of the 
valve. The high stroke rate in conjunction with the mass of the valve 
results in erosion and failure of the valve, the sealing valve insert and 
also the operating mechanisms associated with the valve. The weight of the 
metal valve limits the stroke rate yet the valve must be resistant to the 
wear caused by the pumping fluids and the high shock loads associated with 
the pumping. Moreover, in the event of damage to the guide legs the entire 
valve must be replaced. Accordingly, the guide legs are made thicker to 
reduce breakage thereby further increasing the weight of the valve. All of 
these factors limit the effectiveness and operating life of the past known 
valve assemblies. 
SUMMARY OF THE PRESENT INVENTION 
The present invention overcomes the disadvantages of the past known valve 
assemblies utilized in oilfield applications by providing a reduced weight 
valve which increases the operating life of the valve and facilitates 
repair and replacement. 
The valve of the present invention is adapted to cooperate with a valve 
seat having a full open bore through which the pumping material passes. In 
a preferred embodiment of the present invention, the valve comprises a 
valve head and valve body detachably secured to the valve head. The valve 
head is made of a hardened forged alloy, heat-treated to produce a hard 
case over a ductile steel core in order to provide wear resistance and the 
ability to take high shock loads. In order to reduce the weight of the 
valve, the valve body is preferably made of a urethane material. The valve 
body includes a plurality of guide legs to facilitate proper stroke 
travel. As a result, the weight of the valve is reduced by approximately 
65% while the urethane legs are less likely to shear than the metal guide 
legs of the past known valves. 
The present invention contemplates several alternative means for securely 
attaching the valve body to the valve head. The first alternative employs 
a valve body which snaps together with the valve head. The valve head 
includes an annular cavity formed in its underside which has one or more 
annular grooves formed in the side wall thereof. The valve body includes 
at least one annular flange adapted to be matingly received in a 
corresponding groove. The flange and groove are configured to facilitate 
snap together assembly yet resist separation under the operating stresses. 
A second alternative utilizes a threaded engagement between the head and 
valve body whereby the valve body screws into the valve head. The threads 
are specially configured to facilitate assembly yet resist disconnection. 
A third alternative provides the valve body with a mushroom-shaped upper 
end which cooperates with a similarly configured annular cavity in the 
valve head. All of these configurations facilitate assembly of the valve, 
reduce the weight and therefore the operating mass of the valve, and 
simplify repair and/or replacement. 
Other objects, features and advantages of the invention will be apparent 
from the following detailed description taken in connection with the 
accompanying drawings.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION 
Referring to the drawing, there is shown several embodiments of an improved 
valve construction for use in oilfield applications such as for cementing, 
fracturing or acidizing operations. Referring first to FIG. 1, the valve 
assembly 10 embodying the present invention is utilized in a pump housing 
12 adapted to pump the appropriate fluid either from the surface into the 
borehole or from the borehole to the surface. Typical pumps 12 may include 
several valve assemblies 10 linearly aligned to increase pump volume. 
Because of the demands of deep well drilling, such valve assemblies 10 can 
be subjected to extreme pressures and temperatures. In addition, since 
some modern pumps 12 are capable of hundreds of strokes per minute, the 
valve assemblies 10 are subject to high shock loads as well as errosive 
wear from the material being pumped. The valve assembly 10 embodying the 
present invention combines the ability to withstand such pressures and 
wear while reducing the shock loads associated with the reciprocating 
pumping action of the valve assembly 10. 
Referring now to FIG. 2, the valve assembly 10 generally comprises a valve 
seat 14 having a fluid flow through bore 16 and a valve 18 reciprocatingly 
received by the valve seat 14. The valve 18 includes a combined valve head 
20 and valve body 22. The valve head 20 includes an underside surface 24 
adapted to cooperate with the valve seat 14. A sealing ring 25 may be 
provided on this underside surface 24 to enhance the sealing cooperation 
of the valve 18 with the valve seat 14 when the valve assembly 10 is 
closed. In a preferred embodiment of the present invention, the valve head 
20 is made of a hardened forged metal alloy which is resistant to wear 
while the valve body 22 is made of an elastomer or urethane material 
designed to reduce the weight and therefore the stroke load of the valve 
18. It is contemplated that elastomer materials would be used in fluid 
environments which would not be conducive to urethane materials. The 
integrally molded valve body 22 includes a neck portion 26 and a plurality 
of guide legs 28 extending downwardly from the neck 26. In addition to 
reducing the weight of the valve 22 and therefore increasing its operating 
life, the elastomer/urethane legs 28 are less likely to shear under 
operating stresses than the conventional metal guide legs. Nevertheless, 
if the guide legs 28 do fail, repair/replacement of the valve body 22 is 
easily accomplished as will be subsequently described. 
In a preferred embodiment of the valve 18, the valve head 20 includes an 
annular cavity 30 formed in the underside thereof and configured to 
matingly receive the annular neck portion 26 of the valve body 22. The 
annular neck 26 and cavity 30 include means for lockingly attaching the 
valve head 20 to the valve body 22 such that the valve 18 can reciprocate 
within the valve seat 14 without separation of the valve head 20 and valve 
body 22 yet, if necessary, the valve body 22 can be separated from the 
valve head 20 for repair or replacement. The two-piece construction also 
reduces manufacturing costs since the valve head 20 and valve body 22 are 
more economically manufactured separately and later assembled. 
FIGS. 2 through 4 show a first embodiment of the means for lockingly 
attaching the valve head 20 to the valve body 22. The cavity 30 of the 
valve head 20 is provided with an annular groove 32 and the neck portion 
26 of the valve body 22 is provided a corresponding annular tongue 34 
which is lockingly received within the groove 32 upon assembly of the 
valve 18. Preferably the tongue 34 has a configuration which provides a 
sloped but substantially planar upper surface 36 and a semi-cylindrical 
lower surface 38 giving the tongue 34 a partial tear-drop shape. The 
sloped upper surface 36 facilitates insertion of the neck 26 into the 
cavity 30 by allowing the inner annular surface of the cavity to pass over 
the tongue 34. Conversely, the semi-cylindrical lower surface 38 resists 
removal of the valve body 22 from the valve head 20 by lockingly 
cooperating with the groove 32 which has a corresponding configuration. 
However, the semi-cylindrical configuration does not prevent separation of 
the valve body 22 and valve head 20 if necessary. Although the invention 
is described and shown with the valve head 20 having a neck 26, it is to 
be understood that the valve body 22 may be provided with a cavity which 
receives a neck or post extending from the underside of the valve head. 
Furthermore, the tongue and groove may be reversed such that the cavity 
includes an annular tongue while the neck includes a mating groove. 
In a second embodiment of the present invention shown in FIG. 5, two or 
more tongue 34 and groove 32 combinations may be provided to increase the 
locking engagement between the valve body 22 and the valve head 20. In 
this embodiment, the sloped upper surface 36 allows the uppermost tongue 
to move past the first groove 32. The more tongue 34 and groove 32 
combinations which are provided the more difficult it will be to separate 
the valve body 22 from the valve head 20. Nevertheless, the elastic 
properties of the elastomer valve body 22 will facilitate assembly while 
also permitting disassembly of the valve 18. 
FIGS. 6 and 7 show another snap-fit assembly of the valve head 20 and valve 
body 22. This third embodiment of the invention employs a mushroom-shaped 
neck portion 26 which mates with a similarly configured cavity 30. The 
neck 26 has a larger diameter at its upper end than at its lower end. 
Similarly, the upper end of the annular inner surface of the cavity 30 has 
a greater diameter than the lower end. As a result, the reduced diameter 
portion of the cavity 30 retards withdrawal of the larger diameter portion 
of the neck 26. However, the resilient properties of the urethane neck 
portion 26, and to some extent the cavity walls, allow assembly of the 
valve head and body under sufficient pressure. 
A fourth embodiment shown in FIGS. 8 and 9 utilizes a threaded engagement 
to connect the valve head 20 to the valve body 22. Preferably, the neck 
portion 26 is provided with a single continuous thread form 40 around its 
outer periphery and the inner annular surface of the cavity 30 is provided 
with a corresponding thread groove 42. Although more than one thread may 
be provided, manufacturing costs will increase as a result and one 
continuous thread is sufficient to provide the necessary locking 
engagement. As is best shown in FIG. 9, the thread form preferably has a 
semi-circular cross-sectional configuration. Such a configuration can be 
molded into the elastomer valve body 22 and increases the reliability of 
the assembly by reducing the likelihood of stripping the threads. To 
prevent the valve body 22 from being threaded too far into the valve head 
20, the neck portion 26 includes a terminal annular flange 44 formed 
longitudinally below the thread form 40. The terminal flange 44 will 
engage the head 20 to prevent further rotation and longitudinal movement 
of the valve body 22 with respect to the valve head 20. An annular groove 
46 may be provided to receive the terminal flange 44. In this manner, 
proper orientation of the valve body 22 with respect to the valve head 20 
is assured. Furthermore, the flange 44 cooperates with annular flange 48 
formed on the upper surface of the valve body 22 to form a sealed chamber 
50. The pressure differential between the chamber 50 and the environment 
surrounding the valve 10 acts to further prevent the valve body 22 from 
detaching from the valve head 20. The environment surrounding the valve 10 
is at a higher pressure than the pressure within the chamber 50 thereby 
creating an attraction between the two components. 
Thus, the present invention provides a valve assembly with sufficient 
strength and integrity to be utilized in oilfield applications yet can be 
manufactured, assembled and repaired, if necessary at reduced costs. 
Furthermore, by reducing the overall weight of the reciprocating valve the 
shock loads associated with operation are reduced thereby increasing the 
operating life of the valve assembly. Nevertheless, the means for 
lockingly assembling the valve allow for the use of weight reducing 
materials while assuring integrity. 
The foregoing detailed description has been given for clearness of 
understanding only and no unnecessary limitations should be understood 
therefrom as some modifications will be obvious to those skilled in the 
art without departing from the scope and spirit of the appended claims.