Environmental leakage protector for recirocating rod fluid displacement arrangements

A leakage protector for preventing gases, vapors and liquids emanating as leakage through the seals or packings around the reciprocating rod of reciprocating rod-type fluid displacement arrangements, such as those of pumps, compressors, and the like from reaching the surrounding environment. The leakage protector has an adaptor for mounting a leakage recovery unit of the protector on the casing of the reciprocating rod arrangement in proximity to its packing or seal. The reciprocating rod passes through the leakage recovery unit with clearance, and a bellows component is sealingly attached to the reciprocating rod at one end and to the leakage recovery unit at an opposite end. The interior of the bellows component is able to communicate with the interior of the recovery unit, and the leakage recovery unit is connected to a vacuum recovery line via a vacuum recovery fitting having a valve which causes the vacuum recovery line to be sealed relative to the interior of the leakage recovery unit except when pressure increases occur within the interior of the leakage recovery unit due to the entry of leakage. A fluid sensor can also be provided to shut down operation of the reciprocating rod arrangement, should excessive leakage occur.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to protecting the environment from waste 
gases and fluids produced by leakage in reciprocating rod-type fluid 
displacement arrangements such as those of pumps, compressors, and other 
devices where the potential exists for leakage of a gas or liquid about a 
rod which reciprocates through a casing, pipe, housing, or the like. 
2. Description of Related Art 
Reciprocating rod arrangements are commonly utilized in connection with 
such devices as pumps and compressors acting on toxic gases and liquids; 
for example, oil well pumping units, where a packing gland system or other 
form of seal or packing is utilized to prevent leakage from passing out of 
the arrangement from around the reciprocating rod. However, no matter how 
effective a seal or packing arrangement may be when new, ultimately wear 
on the packing or seal occurs due to the reciprocating action of the rod 
through the packing or seal, and with wear, leakage of vapors and/or 
liquids through the packing or seal occurs. Furthermore, while the extent 
of leakage may not be sufficient to cause shutting down of the equipment 
to replace the seal or packing due to the associated reduction in 
production or the potential for damage to the associated equipment, even 
small amounts of vapor and liquid leakage into the surrounding environment 
creates a measurable amount of pollution and a potential hazard, 
especially where the device is utilized within a building. 
In the case of wells that are located in metropolitan areas or offshore, 
environment concerns are particularly acute, so that frequent servicing of 
the packing or seal around the reciprocating rod becomes necessary to 
prevent leakage that would, otherwise, be considered inconsequential from 
an operational or economic standpoint. Thus, while it is known to provide 
stuffing boxes with leakage detectors (see Truman, et al. U.S. Patent No. 
3,276,246), such arrangements merely serve to terminate operation once 
excessive leakage occurs, and do not deal with the problem of leakage 
occurring under circumstances where, but for environmental/safety 
concerns, there is no need to terminate operation. 
In U.S. Patent No. 4,530,397 to Calhoun, an oil saving apparatus for use 
with a well pump polish rod is disclosed for conserving oil which may leak 
from the stuffing box of an oil well pump polish rod by passing along the 
polish rod when the stuffing box packing wears or dries out. In accordance 
with this patent, a housing is welded onto the top of a conventional 
stuffing box of a well head fitting. The housing contains an auxiliary 
packing, a fluid leakage collection chamber and discharge ducts. Fluid 
leakage collected by the collection chamber and leakage fluid which may 
pass through the collection chamber into the auxiliary packing are drained 
by the discharge ducts into a collection receptacle. While such an 
apparatus may conserve an amount of oil that would otherwise be lost due 
to leakage, since the auxiliary packing will be as prone to wear as the 
conventional packing of the stuffing box of the well head, this apparatus 
will not effectively deal with the problem of protecting the environment 
from waste and other toxic gases passing out along the shaft into the 
environment, nor will it totally eliminate the leakage of fluid into the 
environment. 
Johnston U.S. Patent No. 3,270,810 reflects the need to prevent damage to 
vegetation and property adjacent a well due to the discharge of oil, salt 
water, and gas into the environment, but only to the extent that such may 
be sprayed into the atmosphere and carried by the winds over a large area 
due to a "blowout," i.e., an essentially total failure of the seal. The 
polish rod protector and blow deflector of Johnston is comprised of a 
bonnet into which any blowby oil or water which may occur due to failure 
of the stuffing box will be collected and conveyed, via a discharge 
conduit, to the earth immediately adjacent the well, rather than sprayed 
over surrounding vegetation and into the atmosphere. Furthermore, a 
bellows is affixed to the top of the bonnet and is clamped to the polish 
rod so as to cause the bellows to communicate with the interior of the 
bonnet and to expand and contract with reciprocation of the polish rod. 
The bellows serves the purpose of protecting the polish rod from blowing 
dust and dirt, and results in air breathing in and out of the bonnet, via 
the discharge conduit, as the bellows is reciprocated up and down with the 
polish rod. 
Thus, on the one hand, the presence of a discharge conduit makes the 
Johnston device incapable of achieving the current demand for increased 
environmental protection; and, on the other hand, if the discharge conduit 
were merely to be eliminated, air would no longer be able to breathe in 
and out of the bonnet, so that extension of the bellows would produce a 
suction effect that would increase the tendency for gas and oil to leak 
past the packings, and there would be no means to vent the bonnet of 
accumulated gases and liquids which are collected in it. 
A safety hood apparatus for drilling heads is disclosed in McHenry U.S. 
Patent No. 3,322,198 which is designed for enclosing rotating assemblies, 
such as blowout preventers and strippers of oil well drilling rigs to 
exhaust or remove leakage materials emanating from them. The lower portion 
of the hood is securely fastened to the lower section of a rotating head 
directly above the flow line, while the upper portion of the hood extends 
above the exposed portion of the rotating assembly drive bushings or rings 
and has a hole diameter at that point sufficient to permit withdrawal of 
the preventer and stripper from the hood without removing the hood. 
Furthermore, a suction pump is coupled to the hood and flow line, via a 
suitable conduit, to withdraw any dispersals or suspensions of gas, air, 
dust cuttings, and so forth, from the atmosphere confined by the hood, as 
a result of leakage about the stripper, bonnet, or other parts of the 
rotating assembly, and so as to exhaust such materials to the flow line or 
overflow outlet. To ensure proper operation of the pump, the hole in the 
upper portion of the hood does not form a tight seal and operates to allow 
sufficient air to flow into the hood, which results in a slight positive 
pressure being maintained inwardly of the hood at its upper portion. 
However, the safety hood apparatus of McHenry is not suitable for use in 
reciprocating rod fluid displacement arrangements. Furthermore, on the one 
hand, if an inadequate level of vacuum is not maintained within the hood, 
the portions at which air is able to flow into the hood can serve as sites 
at which leakage gases and liquids can escape, while, on the other hand, 
if a relatively high vacuum is maintained within the hood, the vacuum 
drawn by the pump will undesirably foster leakage. 
Thus, there is still a need for an environmental leakage protector for 
reciprocating rod fluid displacement arrangements, such as pumps, pumping 
units, and compressors, which will effectively protect the environment 
from gases and liquids produced by leakage and reciprocating rod action 
devices without affecting operation or increasing the propensity toward 
leakage. 
SUMMARY OF THE INVENTION 
In view of the foregoing, it is a primary object of the present invention 
to provide an environmental leakage protector for reciprocating rod 
displacement arrangements which will contain any leakage and channel it to 
a proper recovery system while causing no effect on the normal rod action 
or the propensity of leakage to escape past the rod seals or packings. 
It is a further object of the present invention to provide an environmental 
leakage protector for reciprocating rod fluid displacement arrangements 
which will automatically shut down the unit in the event of a major leak 
in the packing or seal area, so that any spillage is contained and not 
discharged into the atmosphere. 
It is still a further object of the present invention to provide an 
environmental leakage protector that will be simple in construction, yet 
applicable to a wide range of devices and units having reciprocating rod 
fluid displacement arrangements as a part thereof. 
These objects are achieved in accordance with the preferred embodiments of 
the present invention through the use of a leakage protector which is 
comprised of a leakage recovery unit having an adaptor for mounting a 
leakage recovery unit of the protector on the casing of the reciprocating 
rod arrangement in proximity to its packing or seal. The reciprocating rod 
passes through the leakage recovery unit with clearance, and a bellows 
component is sealingly attached to the reciprocating rod at one end and to 
the leakage recovery unit at an opposite end. The interior of the bellows 
component is able to communicate with the interior of the recovery unit, 
and the leakage recovery unit is connected to a vacuum recovery line via a 
vapor recovery fitting, and the recovery component also contains a fluid 
sensor. 
Under normal conditions of operation, the vacuum recovery line is sealed 
relative to the interior of the leakage recovery unit by a valve of the 
recovery fitting. However, in the event that a leak should occur, a 
pressure increase will result which, when the bellows contract, will cause 
the recovery fitting to open, thereby allowing the vacuum, in the vacuum 
recovery line, to draw out gases and liquids from the leakage recovery 
unit. In the event that an excessive amount of liquid enters into the 
leakage recovery unit, the fluid sensor will shut down operation of the 
reciprocating rod arrangement. 
These and further objects, features and advantages of the present invention 
will become more obvious from the following description when taken in 
connection with the accompanying drawings which show, for purposes of 
illustration only, several embodiments in accordance with the present 
invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In FIG. 1, a reciprocating rod arrangement in the form of a well pumping 
unit 1, of the well-known horse head type, is shown. In such an 
arrangement, rocking of a horse head beam 3 produces an up-and-down 
movement of a reciprocating rod 5, known as a polish rod, in and out of a 
well head casing 7 through a seal means in the form of a packing gland 
within a so-called stuffing box, as is also conventional. FIG. 1 also 
shows an environmental leakage protector, designated generally by the 
reference numeral 10, for preventing gases and liquids that may leak past 
the packing gland of the stuffing box between the reciprocating rod and 
the casing wall from reaching the surrounding environment. As shown in 
FIG. 1, this leakage protector 10 is provided about the reciprocating rod 
5 in proximity to the seal means within the stuffing box of the well head 
casing 7. 
The leakage protector 10 is comprised of four basic components, two of 
which remain fixed with respect to the casing 7, and two of which follow 
the reciprocation of the rod 5. The stationary components will now be 
described relative to FIG. 2. 
In particular, FIG. 2 illustrates a leakage recovery unit which is mounted 
upon a casing wall forming an end of the reciprocating rod arrangement in 
proximity to the seal means thereof (e.g., on top of the stuffing box wall 
through which the reciprocating rod passes, as shown in FIG. 1) by means 
of an adaptor 14. Adaptor 14 may be a ring clamp which grips both the 
casing wall and recovery unit 12, a cylindrical member that is bolted or 
welded to the recovery unit and/or casing (note bolt holes 14'a and weld 
14'b, FIG. 3) or the like, depending upon the particular construction of 
the reciprocating rod arrangement. Furthermore, while the adaptor 14 has 
been shown as a simple cylindrical member for purposes of illustration, it 
could be given a perimetric securement flange for fastening to the casing 
wall (see FIG. 8), or any other shape conducive to mounting of the 
recovering unit 12 to the particular casing wall of the particular 
reciprocating rod arrangement. Furthermore, to prevent leakage between the 
casing wall and the end of the recovery unit seated thereagainst, an 
O-ring seal 16 is seated in the end face 12a of recovery unit 12. 
Recovery unit 12 is provided with a hollow interior for enabling the 
reciprocating rod 5 to pass through it with clearance, as well as to 
provide a path for leakage fluids, such as oil, gas, and steam. The hollow 
interior 12b can be in the form of a series of chambers (FIG. 2), or can 
be of a uniform diameter (see interior 12'b, FIG. 3) for this purpose. 
At the opposite end of recovery unit 12 from end face 12a is a bellows seat 
12c upon which an end of a bellows component 18 is seated and secured in 
an airtight fashion via a ring clamp, force fit, or the like. Bellows 
component 18 may be comprised of one or more bellows 20, each of which has 
a cylindrical array of accordian folds 20a and a pair of mounting sleeve 
portions 20b. The bellows is mounted to the recovery unit 12 by one of the 
mounting sleeves 20b, as already described, and by the other, to the 
reciprocating shaft 5, as will now be explained. 
For causing the bellows 20 to expand and contract with reciprocation of the 
rod 5, a bellows mount 22 is secured on the reciprocating rod 5 via, for 
example, a plurality of set screws 24. The bellows mount 22 has a bellows 
seating portion over which a bellows sleeve portion 20b is secured in an 
airtight manner, such as by a ring clamp (not shown). Furthermore, in 
order to ensure that gases cannot escape from the bellows through the 
junction of the bellows mount 22 and the reciprocating rod 5, an O-ring 26 
is positioned within a recess of the through passage for the rod 5, so as 
to sealingly engage against the rod when the bellows mount 22 is fixed 
thereon. The bellows can be formed of any sufficiently flexible material 
which is chemically resistant to the leakage fluids to which it will be 
exposed, stainless and specialty steels being preferred for high pressure 
applications. 
The position of the bellows mount is set at a distance from the bellows 
sleeve portion 12c of the leakage recovery unit 12 that corresponds to at 
least the stroke length of the reciprocating rod 5, and is coordinated to 
the length of the bellows component 18 so that, when the rod is maximally 
retracted (solid line position, FIG. 1), the bellows 20 will be, 
preferably, extended to 90% of its fully extended length. However, beyond 
a certain bellows length L (FIG. 4), which is a function of the diameter 
and material of which the bellows is composed, there is a tendency for 
bellows to deform so as to deflect against one side of the rod as it is 
compressed, thereby causing the rod to rub against and ultimately damage 
the bellows. For this reason, in environments where the stroke length of 
the reciprocating rod will cause such a bellows deformation problem, if a 
single long bellows is used, a bellows component 18 is utilized which is 
formed of a plurality of bellows 20, with each pair of bellows 20 being 
connected by a floating bellows connector 26. 
The floating bellows connector 26 has a pair of bellows mounting seat 
portions 26a, upon which a respective bellows mounting sleeve portion 20b 
will be clamped in an airtight fashion. Furthermore, in order to permit 
the bellows to expand and contract jointly, as well as to enable gases and 
vapors to be collected in each bellows, the floating bellows connector has 
a through passage 26b which is sufficiently oversized relative to the 
diameter of the reciprocating rod 5 to enable free movement thereof over 
the rod 5, as well as free communication between the pair of bellows 
connected thereby. 
Inasmuch as the above-described leakage protector 10 forms an airtight 
enclosure upon the well head casing 7, in order to prevent the bellows 
component from creating a vacuum that would act to increase leakage 
through the stuffing box, the leakage protector 10 should be installed 
with the reciprocating rod 5 when the rod is in its retracted position. On 
the other hand, to prevent damage to the bellows due to increased 
pressures associated with leakage fluids being accumulated within the 
hollow interior 12b of the recovery unit and leakage gases and vapors 
accumulated within the bellows, the leakage recovery unit 12 is provided 
with a leakage recovery fitting 30 by which the hollow interior 12b of the 
leakage recovery unit 12 can be communicated with a vacuum recovery line 
40, but only in the event of a leakage produced pressure buildup within 
space 12b. Vacuum can be applied to the vacuum recovery line 40 via a 
standard gas gathering line or a compressor which, in turn, puts the 
recovered fluids into, for example, a product line 45 from the well casing 
7. 
A preferred embodiment of a simple, adjustable vacuum responsive recovery 
fitting 30 of a check valve type is illustrated in FIG. 7. This fitting 30 
can be either press fit or threaded into one of a pair of radial bores 12d 
that extend through the leakage recovery unit from hollow interior 12b to 
the exterior. The illustrated embodiment for recovery fitting 30 is 
comprised of a body 31 and a closure 33. The closure 33 is provided with 
an internally threaded vacuum port 33a for attachment of vacuum recovery 
line 40 to fitting 30. Cover 33 is also provided with an external 
threading by which it can be threaded into a matching internal threading 
31a of a valve chamber 31b formed in the body 31, a gasket 35 being 
provided to ensure that an airtight sealing of the recovery fitting is 
obtained. 
A ball valve member 37 is biased into a position closing a valve port 31c 
via a spring 39 that is prestressed by engagement against a spring seat 
33c of the closure 33, when closure 33 is threaded into chamber 31b. By 
selecting a spring having a suitable spring constant, flow from the hollow 
interior of the leakage recovery unit 12 to the vacuum recovery line 40 
will be blocked by the valve member 37 below a predetermined positive 
pressure and will be permitted, by unseating of the ball valve member 37 
against the biasing force of spring 39, when the pressure within the 
hollow interior 12b of the vacuum recovery unit 12 is above that 
predetermined positive pressure. In this regard, the value of spring 39 
should be selected so that under normal operating conditions, when no 
leakage is escaping between the reciprocating rod and the casing wall 
through which it passes into the recovery unit 12, a positive pressure 
will be maintained in the hollow interior 12b during both contraction and 
expansion of the bellows component 18. On the other hand, the spring 
constant should be low enough so that, when the pressure within the 
recovery unit 12 builds up due to the presence of leakage fluids within 
its hollow interior, the ball valve member 37 will become unseated to 
allow excess pressure to be sucked out by the vacuum line 40, thereby 
preventing damage to the bellows component 18. 
Furthermore, it is also desirable to enable the prime mover of the 
reciprocating rod arrangement to be shut down to stop the reciprocating 
action of the rod when excessive leakage of fluid occurs, but before total 
failure of the seal. In this way, in a static condition, the leaking 
packing, normally, will be able to hold back the pressure and fluid until 
remedial action can be taken. To this end, a liquid level switch 50 can be 
inserted into the second radial bore 12d. Numerous commercially available 
products will be suitable for this purpose. For example, the Robertshaw 
Controls Company produces a Model 741 probe that can be used in 
conjunction with Robertshaw's Model 304B electronic, capacitance-actuated 
on-off control instrument for detecting the liquid level within the 
recovery unit 12 as a function of capacitance changes, and for providing 
an output capable of driving an electromechanical control relay circuit 
when the detected value exceeds a reference value. Of course, numerous 
other equivalent devices will be known to those of ordinary skill in the 
art and the use of any particular type of level sensor, per se, forms no 
part of this invention. 
While the above description of the features of the leakage protector in 
accordance with the present invention will be recognized as providing a 
simple and effective means for completely eliminating the escape of 
vapors, gases, and liquids emanating from worn packings and seals around 
reciprocating rods in a reciprocating rod arrangement, it should also be 
recognized that only some exemplary forms for preferred embodiments have 
been mentioned for one particular type of application, the invention being 
adaptable to meet the requirements of any reciprocating rod arrangement. 
Thus, for situations where relative rotational movement between the casing 
mounted recovery unit 12 and the rod mounted bellows component 18 is 
required, such as in arrangements where the packing gland has to be 
rotated to adjust the packing, a leakage recovery unit of the type shown 
in FIG. 3 can be used. The recovery unit 12 of FIG. 3 is illustrated with 
parts that correspond to those of the FIG. 2 recovery unit being 
designated with like reference characters, but being distinguished by 
prime (') designations. The embodiments of FIGS. 2 and 3 are essentially 
the same in function and structure, except that the body of the recovery 
unit 12' is subdivided into upper and lower parts 12'e, 12'f, 
respectively, which are connected together in a manner which permits 
relative rotational displacement therebetween. 
More particularly, the upper body part 12'e is provided with a tubular 
extension which is sized to pass with clearance through the lower body 
part 12'f and is secured in place with only nominal axial play relative to 
lower body part 12'f via a snap ring 47. Furthermore, in order to 
facilitate rotational sliding movement between the facing end surfaces of 
the parts 12'e, 12'f, a disk 48 of low friction material, such as 
polytetrafluorethylene, is position therebetween. Still further, to 
prevent leakage from escaping through the clearance gap between the 
extension of the upper part 12'e and the surrounding internal surface of 
lower part 12'f, an O-ring seal 49 can be mounted within an annular groove 
in the internal surface of lower part 12'f so as to be sealingly 
compressed against the facing external annular surface of the tubular 
extension 12'g of upper part 12'e. With such a swivel arrangement, the 
bellows component 18, vacuum fitting 30, vacuum line 40, and liquid level 
responsive shutoff switch 50 can remain stationary, while the packing 
gland attached to the bottom portion of the adaptor 14' is rotated to 
tighten the packing. 
Still further, as shown in FIG. 8, a leakage protector 10', in accordance 
with the present invention, can be mounted to a compressor 60, instead of 
an oil well pumping unit. The protector 10' differs from that of FIGS. 2 
and 3 only in that the adaptor 14" is formed as an integral part of the 
recovery unit 12' and is in the form of a radial flange having bolt holes 
through which it can be secured to the casing wall 65 of the packing gland 
67 via the same bolts 69 normally used to secure the casing wall 65 
closing the packing gland 67. The details of compressor 60 form no part of 
the present invention and, thus, will not be described, itself, the 
invention being applicable to any other type of reciprocating rod 
compressor as well. 
Accordingly, the present invention should not be viewed as limited to the 
specific features of the various embodiments disclosed herein because 
numerous variations and other embodiments and applications of the 
invention will be apparent to those of ordinary skill in the art from the 
foregoing teachings. Instead, the present invention should be viewed as 
encompassing everything within the scope of the appended claims.