Liveload assembly for rotary or reciprocating shaft packing

A liveload assembly including an stack guide, compressed belleville washers stacked inside the stack guide and a retainer to hold the compressed washers in the stack guide. A longitudinal slot in the wall of the stack guide permits visual checking of the compression provided by the liveload assembly on the gland follower of the valve or pump. The rotary or reciprocating shaft of a valve or pump is liveloaded by placing the liveload assembly over the bolt securing the gland follower to the stuffing box. A nut is threaded on the bolt until it contacts the washers and the retainer removed.

TECHNICAL FIELD 
The present invention relates to the prevention of stuffing box packing 
leakage. More particularly, the present invention relates to a liveloading 
assembly that maintains a proper gland bolt load on the stuffing box of a 
pump, valve or like fluid-flow apparatus, to a method of manufacturing the 
liveloading assembly, and to a method of installing the liveloading 
assembly. 
BACKGROUND OF THE INVENTION 
Fluid flow equipment including pipes, valves, and pumps are common in the 
utility, refinery, manufacturing, chemical and petrochemical industries. 
The mechanical workings of such valves and pumps are housed in casings 
through which rotary or reciprocating shafts extend. For example, the 
shaft of a rotary pump operatively connects a motor on the exterior of the 
casing to an impellor on the interior of the casing. The shafts rotate or 
reciprocate in response to a number of specific stimuli, including a knob 
turned by hand, a motor, or an impeller driven by fluid flowing in the 
equipment. 
Thus, there are at least three openings in a pump or valve casing: (1) an 
opening for an inlet pipe by which fluid is delivered; (2) an opening for 
an outlet pipe by which fluid is discharged; and (3) an opening for the 
shaft. Various types of seals prevent leakage of fluid from the pump or 
valve casing. The two fluid openings for the inlet and the outlet pipes 
are sealed conventionally. The shaft projects through the casing in an 
area known as the "stuffing box" or the "packing box." The terms "stuffing 
box" and "packing box" are interchangeable, and derive from the method of 
preventing fluid leakage by stuffing or packing a material around the 
shaft to provide the seal. The packing material is often composed of woven 
or braided fibers formed into coils, spirals or rings. The packing 
material is stuffed around the shaft so that no fluid can escape the 
casing along the shaft. A lubricant is often impregnated in the packing 
material to facilitate installation and to reduce friction on the packing 
material. 
Rotary and reciprocating shaft-equipped pumps, valves, compressors, 
agitators and the like, interact with a variety of fluids. Such fluids may 
be as harmless as cool water or as dangerous as a radioactive, superheated 
acid. Preventing leakage of any fluid from the opening for the shaft is 
important. The cost of any such leakage can range from the loss of fluid 
and operating time for repair of the leak, to significant environmental 
damage and loss of life. 
For example, consider a pump in a nuclear fueled steam generating plant. In 
nuclear reactors, pumps are used to circulate a coolant (oftentimes water) 
across nuclear fuel elements. The coolant and nuclear fuel are placed 
together in a pressure vessel. Piping from the pressure vessel delivers 
the coolant, heated by contact with the nuclear fuel, to a heat exchanger. 
The heat exchanger extracts the heat from the coolant. The piping thus 
forms a continuous loop between the pressure vessel and the heat exchanger 
so that the coolant is continuously recycled. As a result, radioactivity 
is safely contained within this closed system. Pumps are often provided 
between the pressure vessel and the heat exchanger to deliver the coolant. 
Any leakage from the pump destroys the closed system and permits 
radioactive coolant to escape. Failure of a seal in this example will not 
only result in the discharge of a toxic material into the environment, but 
could cause an explosion or fire. 
In addition to actual damage caused by leaks, profits and the health and 
welfare of employees are affected. Many industrial processes require large 
amounts of time to regain normal operation. Frequent shutdowns of the 
process greatly affect production capability. Thus, having to shut down a 
plant for any period of time in order to replace worn or damaged packing 
in the stuffing box reduces operating time and, correspondingly, reduces 
profit. Moreover, workers are often at risk in replacing such worn 
packing. For example, the packing in a pump and valve becomes saturated 
with the fluid being sealed. The packing in a pump used to circulate 
coolant in a nuclear reactor will be exposed to radioactivity from the 
coolant. A worker who removes old and worn packing from such a pump is, 
for a time, exposed to the radiation contained in the fluid and saturated 
in the packing. Accordingly, frequent replacement of the packing material 
in the stuffing box is not desirable. Moreover, it is preferred that all 
steps be taken to minimize the risk of such radiation exposure. 
Rotating and reciprocating shafts are difficult to seal. In operation, such 
shafts are capable of both radial and axial displacement. Radial 
displacement typically results from manufacturing inaccuracies. Axial 
displacement results from different thermal expansions produced through 
normal operation of the shaft. Furthermore, the stuffing box environment 
is less than ideal. Conditions are constantly changing. The packing may be 
required to withstand high temperatures and pressures one minute and low 
temperatures and pressures the next. Shaft speeds may also vary. The 
surfaces of the shaft in the stuffing box are often pitted and rough. Very 
slight defects in the arrangement or condition of a stuffing box can 
prevent proper pump operation. 
Various types of packing for a stuffing box are known in the prior art. 
Each of these packings attempts to be responsive to the foregoing 
considerations. The packing must be somewhat plastic so that it can 
extrude enough to seal rough or uneven surfaces. The packing must be 
resilient in order to adapt to changing conditions without failing or 
damaging the shaft. However, in trying to provide flexibility, some 
packings sacrifice resiliency. Others, in trying to resist extrusion, 
sacrifice flexibility sufficient to conform to uneven or rough surfaces 
within the stuffing box. Still other packings are flexible, resilient and 
minimize friction, but do not provide a long-lasting seal so as to avoid 
frequent replacement. 
Soft packing is a common shaft seal, and is generally made from asbestos, 
fabric, hemp or rubber fibers woven into strands and formed into a braided 
spiral. Soft packing is inexpensive and offers several desirable features. 
The softness of the packing allows it to absorb energy without damaging 
the rotating shaft. Soft packing is also very flexible and readily 
conforms to the area to be sealed. 
Soft packing, however, has several disadvantages. One problem is short 
life. Soft packing is easily worn by friction and easily damaged, 
therefore requiring frequent replacement. Soft packing may be impregnated 
with graphite or lubricating oils to reduce friction between the shaft and 
the packing, but such lubricants quickly dissipate and are not very 
effective in overcoming the short life problem. Thus, soft packings are 
best suited for low shaft speed applications involving non-caustic and 
non-abrasive fluids. Yet another problem with soft packing is a lack of 
resiliency. After being compressed and extruded, soft packings are unable 
to re-expand to effectuate a seal. Resiliency, conventionally defined as 
the ability of packing to re-expand, is important to enable the packing 
material to adjust to changing conditions. Lack of such resiliency, as in 
the case of a soft packing, results in frequent adjustment or replacement 
for the packing. 
U.S. Pat. No. 3,404,061 teaches a sealing material made from expanded 
graphite. One common use of such material is to wind a length of flexible 
tape made therefrom onto a mandrel to form a solid annulus of appropriate 
size to pack the stuffing box. Thus, the expanded graphite tape is formed 
as a seal. Packing made from expanded graphite is flexible and conforms to 
uneven surfaces. The graphite material makes the packing self-lubricating, 
thereby minimizing friction between the shaft and the packing. With such 
self-lubricating packings, the lubricant does not dissipate with time. 
Expanded graphite packing also absorbs energy without excessive damage to 
either the packing or the shaft. 
The principal problem with expanded graphite packings is a lack of 
resiliency and excessive extrusion under high temperatures and pressures. 
Solid graphite packings are not able to withstand high pressures since 
they lack the internal strength to resist extrusion and are unable to 
re-expand after compression. In addition, expanded graphite packings 
require frequent adjustment under normal conditions due to the low 
resiliency of the graphite. The graphite packings are easily compressed, 
thereby contributing to the low resiliency problem. As a result, normal 
rotation or reciprocation of the shaft can compress the graphite and 
create leaks. 
A further problem with soft packings (and expanded graphite packing in 
particular) is that they are difficult to extract from the stuffing box 
when replacement is necessary. Soft packing can extrude to such an extent 
that it melds to the walls of the stuffing box, making removal difficult. 
Those skilled in the art will appreciate that the typical stuffing box 
provides an annular recess about the shaft, into which the packing is 
stuffed. The recess is capped by a gland follower. The gland follower is 
secured to the casing, known as the gland of the stuffing box, by one or 
more bolts. Thus, the more torque applied to the gland bolts, the greater 
the downward pressure applied to the packing by the gland follower. 
Tightening the gland bolts compresses the packing in the stuffing box to 
effect the seal. 
Generally speaking, there are three conditions that result in leakage: 
packing consolidation; bolt creep; and improper loading. 
Packing consolidation occurs naturally, and refers to the packing's 
tendency to settle, wear, and loosen over time. A number of factors 
contribute to this condition, including the constant rotation of the 
shaft, changes in temperature of fluids flowing through the equipment, and 
the age and material of the packing itself. Soft packing is particularly 
susceptible to consolidation. 
Bolt creep is a condition wherein the gland bolts are moved upward due to 
the expansion and contraction of the gland follower and the casing. Such 
expansion and contraction often results from a change in operating 
temperatures and pressures. Valves and pumps in various industries often 
operate under conditions ranging from cyrogenic to superheated 
temperatures, and normal to extreme pressures and vacuums. Bolt creep 
reduces the pressure applied by the gland follower on the packing. 
Improper loading is a condition wherein the compression exerted by the 
gland follower on the packing is insufficient to effect a seal. Packing 
consolidation and bolt creep are contributing elements of improper 
loading, because both reduce the compressive force applied by the gland 
follower on the packing. But inaccurate torquing of the gland bolts by 
workers also causes improper loading. Such inaccurate torquing may be the 
result of human errors. However, it is recognized that the torque wrenches 
used by workers are often inaccurate, resulting in improper loading. Leaks 
thus occur from the outset because the load on the packing is insufficient 
to achieve or maintain a seal. 
Fluid leakage along the shaft of valves and pumps has long been recognized 
as a serious problem in power and industrial plants. In recognition of 
this problem, various attempts have been made to obtain leak-free 
performance and reduce maintenance requirements for a pump or a valve. For 
example, improved packing materials were developed for a larger range of 
temperatures, better chemical resistance, and improved coefficient of 
expansion characteristics. Torque values were established for the bolts 
connecting the gland follower to the stuffing box. (Installers follow such 
specifications to apply a proper load to the packing to achieve a seal, 
but as discussed above, may not attain a proper load because the torque 
wrenches are inaccurate.) Several companies have initiated routine 
maintenance programs that include re-torquing of gland follower bolts. 
Such retorquing is done frequently because of the significant risk posed 
by improperly loaded gland bolts and the resulting leakage of fluid from 
the apparatus. The costs of repairing damaged equipment and cleaning up 
spent fluids are also of concern. But generally, the majority of the 
equipment does not need such maintenance. Such maintenance programs 
include all equipment, however, in order to correct the torque on the 
relatively few pieces of equipment for which packing compression is 
lessened (as a result of bolt creep, packing consolidation or previous 
improper loading) to an extent that leaking has occurred or could occur. 
Another attempt to obtain leak-free performance and reduce maintenance 
requirements involves liveloading of the gland follower. Liveloading 
refers to the mounting of compressed springs on the gland follower whereby 
a constant pressure is exerted on the gland follower to insure a constant 
compressive force is exerted on the packing. As the packing consolidates 
or the gland bolts loosen, the spring pressure moves the gland follower 
towards the stuffing box to maintain the integrity of the packing. 
Belleville washers are one type of spring typically used to cushion heavy 
loads with short motion. Uncompressed belleville springs or washers 
typically take the form of a disk with an open center. In contrast, 
compressed belleville washers are flat. A significant amount of force is 
required to compress or flatten the uncompressed belleville washers. 
Belleville washers installed on the gland bolts of pump and valve stuffing 
boxes maintain the force exerted by the gland follower on the packing. As 
the packing consolidates or the gland bolts loosen, the belleville washers 
decompress and maintain the load on the packing. The gland follower 
essentially becomes self adjusting in response to the packing's condition 
to maintain a proper load on the packing and thereby maintain a seal. 
Liveloading a gland follower is difficult in many situations. It is 
particularly difficult to retrofit valves for liveloading for a number of 
reasons. Replacement of bolt studs may be necessary because the studs are 
not long enough to accomodate a sufficient number of uncompressed 
belleville washers and the nut that conventionally maintains the gland 
follower. Those skilled in the art will appreciate that uncompressed 
belleville washers occupy more space than compressed washers. Accordingly, 
the gland bolts must often be extruded and replaced with longer bolts. 
This is particularly expensive in nuclear power plants, not only because 
expensive high grade steel material must be used to manufacture the 
extended bolts, but also because a significant amount of paperwork 
detailing the change must be prepared and filed with the various 
regulatory agencies and manufacturers involved with the equipment and 
nuclear power plants. Also, health and safety inspectors at nuclear plants 
track carefully the amount of radiation to which workers are exposed 
because there is a limit to the amount of radiation a worker may receive. 
Additional workers thus may be needed for simple, yet time-consuming 
projects. 
Another reason that liveloading is difficult is because achieving the right 
load on the belleville washers is expensive and difficult. The retaining 
nut must be torqued on the bolt to a specific degree to achieve and 
maintain a seal. Proper torquing of the washers, even using torque 
wrenches, takes a long time. In a nuclear plant, any additional 
maintenance time increases the workers' exposure to radiation from the 
fluid. Torque wrenches are recognized as inherently inaccurate. Engineers 
at nuclear plants in particular are uncomfortable relying on such tools to 
achieve a proper torque. 
Yet another reason that liveloading is difficult is because belleville 
washers are difficult to install about a gland bolt. Aside from being a 
time consuming operation, the component washers are small in size and 
difficult to manipulate. Workers in heavily radiated areas must wear 
several sets of gloves and a respirator. Gloves make such small objects 
difficult to handle and position over a bolt. The respirator makes it 
difficult to see. If a single belleville washer is dropped and lost, work 
may be delayed for hours. 
A further reason that liveloading is difficult is that belleville washers, 
once placed on a gland bolt and even when properly torqued, may slip 
laterally and hang or catch on the bolt. This causes hysteresis, a 
retardation of the self-adjusting effect of the belleville washers on the 
gland follower. 
Thus, there exists a need in the art for an apparatus for liveloading, and 
for a method of preparing an apparatus for liveloading, the gland follower 
that is free of the problems typically experienced when liveloading 
valves, pumps and the like in power and industrial plants. 
SUMMARY OF THE INVENTION 
The present invention provides a liveload assembly of belleville washers 
precompressed to a predetermined load for installation on a gland bolt. 
The liveloading assembly of the present invention includes a stack guide 
and a plurality of belleville washers stacked inside the stack guide. A 
retainer holds the compressed washers in the stack guide. 
The preferred stack guide is a cylinder with an open top end and a bottom 
end with an aperture coaxial with the longitudinal axis of the cylinder. 
The aperture is sized to permit the stack guide to pass over the gland 
bolt of the equipment on which the liveloading assembly is to be 
installed. The inner wall of the stack guide is threaded from the top end 
towards the bottom end. A slot in the wall of the stack guide extends 
downwardly from the top end towards the bottom end. The slot permits 
visual checking of the compressed washers to provide an indicator showing 
the extent to which the washers have decompressed. 
The stack guide receives the plurality of belleville washers, each washer 
formed with a center opening of suitable dimension to pass over the gland 
bolt. 
The preferred retainer is an open ended cylinder having a threaded exterior 
surface and a hex head machined in one end of the cylinder. The retainer 
is sized so as to be threadably received by the stack guide, thereby 
holding the belleville springs within the stack guide. The retainer 
defines a center opening of sufficient diameter to permit a gland bolt nut 
to pass there-through. 
The liveload assembly of the present invention is preferably assembled by 
stacking uncompressed belleville washers inside the stack guide. The 
belleville washers are then compressed. The washers are held compressed in 
the stack guide by threading the retainer into the stack guide. 
The liveload assembly is preferably installed by sliding the assembly over 
a gland bolt threaded into the gland follower. A nut is threaded onto the 
bolt until it contacts the compressed belleville washers in the assembly. 
The retainer is then removed from the stack guide by gripping the hex head 
with a wrench and turning the retainer. The gland follower, and hence, the 
packing in the stuffing box, is liveloaded by the compressed washers. As 
the gland follower travels over time towards the casing, the stack guide 
moves with respect to the gland bolt. When the stack guide reaches a 
predetermined position with respect to the gland nut, as revealed by the 
slot, the nut is to be retorqued to recompress the belleville washers and 
thereby maintain a proper force on the gland follower and, in turn, on the 
packing in the stuffing box. 
Accordingly, it is an object of the present invention to provide a 
liveloading assembly with compressed belleville washers preloaded in an 
assembly for installation on a gland bolt. 
It is an object of the present invention to provide a liveloading assembly 
permitting a gland follower to be preset to a predetermined torque. 
It is an object of the present invention to provide a liveloading assembly 
that reduces the time for installing belleville washers on a gland bolt. 
It is an object of the present invention to provide a liveloading assembly 
that simplifies the installation and torquing of belleville washers on 
gland bolts to liveload the gland follower. 
It is an object of the present invention to provide a liveloading assembly 
that reduces worker exposure to radiation when installing liveload 
belleville washers on valves in a nuclear plant. 
It is an object of the present invention to provide a liveloading assembly 
that permits retrofit liveloading of valves or pumps without having to 
replace the gland bolts with longer bolts. 
It is an object of the present invention to provide a liveloading assembly 
that reduces reliance on inaccurate torque wrenches used to liveload the 
stuffing box of a rotary or reciprocating shaft by providing belleville 
washers in an assembly preloaded to a calibrated compression. 
It is an object of the present invention to provide a liveloading assembly 
that provides a liveload belleville washer assembly for a gland follower 
which compresses the packing in a stuffing box seal of a shaft. 
It is an object of the present invention to provide a liveloading assembly 
that provides an indicator flagging a rotary or reciprocating shaft having 
liveload belleville washers which need to be retorqued. 
It is an object of the present invention to provide a liveloading assembly 
that reduces the costs of routine valve and pump maintenance for 
re-torquing gland follower bolts by mechanically flagging a bolt which 
needs to be retorqued.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now in more detail to the drawings, in which like numerals 
indicate like parts throughout the several views, FIG. 2 illustrates an 
exploded perspective cut-away view of the liveload assembly 12 including 
an stack guide 38, a plurality of belleville washers 40, and a retainer 
42. 
The top end 44 of the cylindrical stack guide 38 is open while the bottom 
46 defines an aperture 48. The aperture is coaxial with the longitudinal 
axis of the stack guide 38. The interior of the stack guide 38 is threaded 
with a thread 45 from the top 44 a predetermined distance towards the 
bottom 46. A slot 49 in the wall of the stack guide 38 extends 
longitudinally from the top end 44 a predetermined distance towards the 
bottom end 46. Preferably, the slot 49 extends to the longitudinal point 
which the uppermost belleville washer 40a will occupy when the assembly is 
loaded. The belleville washers 40 are ring-like dished disks which flatten 
when compressed. 
The retainer 42 is preferably a cylindrical open ended tube with the hex 
head 52 machined in one end. An exterior portion 50 includes a thread 51 
to mate with the interior thread 45 of the stack guide 38. 
FIG. 2 further illustrates a piston 37 and a support 39 in a hydraulic 
press (not illustrated) which cooperate with a cylindrical rod or tube 54 
to load the liveload assembly 12. As will be described in more detail, 
loading is accomplished by compressing the belleville washers 40 and 
securing the washers 40 with the retainer 42. A compressed liveload 
assembly 12 may then be installed on the gland follower of a pump or valve 
casing. For instance, in FIG. 1, there is shown in a cross-sectional view 
a casing 10 including an embodiment of the precompressed liveload assembly 
12 which maintains compressive force on the packing in the stuffing box. 
The casing 10 is representative of a casing for either a pump or valve. 
Both may use a stuffing box seal to reduce or eliminate leaks through the 
valve or the pump. For discussion purposes, the casing 10 will be 
considered part of a pump 13. The pump 13 includes a discharge side 14 and 
an inlet side 16. A rotatable shaft 18 connects to an impellor (not shown) 
at one end and to a motor (not shown) at the other end. A bushing 20 
supports the rotatable shaft 18 in the pump 13. 
The casing 10 of the pump 13 defines a gland stuffing box 22. The stuffing 
box 22 defines an annular region 23 through which the shaft 18 extends. 
Compression packing 24 is held in the annular region 23 of the stuffing 
box 22 to seal the casing 10 and prevent fluid leakage along the shaft 18. 
The illustrated embodiment includes a lantern ring 26 which communicates 
with an aperture 28 for the introduction of lubricants to the packing 24. 
A gland follower 30 includes an annular flange 32 which inserts in the 
annular region 23 of the stuffing box 22. The gland follower includes 
bores 33. A bolt 34 connects to the stuffing box 22 by threadably engaging 
a bore 35. The bolt passes through one of the bores 33. A nut 36 on each 
bolt 34 retains the liveload assembly 12 (and 12a shown in cut-away view) 
securely to the top of the gland follower 30. The compressed belleville 
washers 40 push against the nut 34 and the gland follower 30 to maintain 
the compressed load on the packing 24 in the stuffing box 22. 
The stack guide 38 accordingly defines a cup in which the belleville 
washers 40 fit. In a preferred embodiment, the outside diameters of the 
belleville washers 40 have about 0.0025 inch clearance overall to fit in 
the interior of the stack guide 38. The aperture 48 in the bottom 46 of 
the guide 38 is drilled to fit over a gland bolt 34, also preferably with 
about a 0.0025 inch clearance. 
In a preferred method of loading the liveload assembly 12 of the present 
invention, the stack guide 38 as shown in FIG. 2 is placed on a support 
39. The appropriate number and size of belleville washers 40 are placed 
inside the stack guide 38. The retainer 42 is threaded into the open end 
44 of the stack guide 38. A tube or bar 54 is inserted coaxially through 
the retainer 42 to contact the top belleville washer 40 in the stack guide 
38. The hydraulic press is activated and the piston 37 moved downward. The 
piston 37 pushes on the tube 54 compressing the belleville washers 40. A 
gauge (not illustrated) connected to the hydraulic press provides an 
indicator permitting compression of the belleville washers to a specific 
loading. An ordinary wrench is placed on the hex head 52 of the retainer 
42 and the retainer 42 is turned into the stack guide 38 until the bottom 
of the retainer 42 contacts the top belleville washer 40a. The hydraulic 
press is released withdrawing the piston 37, and the tube 54 is removed 
from the assembly 12. The preloaded assembly 12 is ready for storage, 
shipping and installation on a valve or a pump. 
In an alternate assembly method, the stack guide 38 and the retainer 42 are 
threaded after determining the compressed, loaded position of the washers 
in the stack guide 38. The stack guide first is placed over a bolt or stud 
on a support (not illustrated). The appropriate number and size of 
belleville washers 40 are placed inside the stack guide 38. The belleville 
washers 40 are then loaded by compressing with a hydraulic press or using 
torque wrenches. When the proper load is achieved, a precise measurement 
of the washer stack height is taken and the washers are unloaded and 
removed from the stack guide 38. 
The inside surface of the stack guide 38 is then threaded from the top 44 
towards the bottom 46. In a preferred embodiment, the thread 45 is cut to 
about one turn above the previously marked belleville washer compression 
height. The bottom portion 50 of the retainer 42 is then cut with the 
mating thread 51. 
The stack guide 38 is re-positioned on the bolt (not illustrated). The 
belleville washers 40 are placed back on the bolt 34 inside the stack 
guide 38 and reloaded with a nut (not illustrated). Turned with a torque 
wrench, the nut compresses the belleville washers 40. The nut is torqued 
to the marked height representing the predetermined compression load for 
the washers 40. The retainer 42 is threaded and screwed down into the 
stack guide 38 until the thread stops. This is about one turn above the 
washer compression height. The nut is loosened and the washers 40 
uncompress the distance between the mark and the bottom of the retainer 
42. The liveload assembly with the washers in the preloaded position is 
ready for storage, shipping and installation on a valve or pump. The 
liveload assembly 12 from this alternative method has compressed washers 
40 preloaded to a position approximately within 0.002 inch of the intended 
load position because installing the retainer 42 permits the washers 40 to 
decompress about one thread turn. 
With reference to FIG. 1, the gland follower 30 may be liveloaded by first 
installing the packing 24 in the annular region 23 of the stuffing box 22. 
The bolts 34 thread into the bores 35 of the stuffing box 22. The gland 
follower 30 is positioned with the annular flange 32 in the open top of 
the annular region 30 of the stuffing box 22. The bores 33 align with the 
bolts 34 as the gland follower is positioned over the stuffing box. One 
liveload assembly 12 is positioned over each bolt 34. The gland nut 36 is 
tightened by hand until it reaches the top of the washers 40. A standard 
wrench is then used to tighten the gland nut 36 one turn. This compresses 
the belleville washers 40 to the intended loading height. It also relieves 
the pressure from the belleville washers 40 on the bottom of the retainer 
42. The retainer 42 is then removed. 
As the packing 24 consolidates and compresses, the gland follower 30 is 
pushed axially by the liveload assemblies 12 and 12a towards the stuffing 
box 22 to maintain compression on the packing 24. When the gland follower 
30 moves, the compression on the belleville washers 40 lessens. Movement 
of the gland follower 30 causes the stack 38 to move axially with respect 
to the bolt 34. The slot 49 in the stack guide 38 permits visual 
monitoring of the load provided by the liveload assembly 12. A preferred 
embodiment uses belleville springs with linear regressive load deflection. 
Such belleville springs provide a direct correlation between the 
compression lost by changes in the packing 24 and the movement of the 
stack guide 38 relative to the gland nut 36 threaded onto the bolt 34. 
Other types of belleville washers will work with the stack guide 38 and 
retainer 42 of the present invention, but to equate deflection to 
compression requires reference to a formula or the manufacturer's spring 
table specifications. 
It is advantageous to paint the edge of the top belleville washer 40a with 
a florescent paint prior to loading the washer in the stack guide 38. A 
mark also made with florescent paint may be applied to the stack guide 38 
between the top and bottom of the slot 49. When the top belleville washer 
40a reaches the stack mark, then the liveload assembly should be retorqued 
to specifications. Use of florescent paint permits visual checking of the 
load condition by flashlight. The mark on the stack guide 38 is made at a 
point where 60 percent of the compressive force is lost. Depending on 
particular requirements and specifications, the mark may be positioned to 
reflect any desired portion of capacity used. Marking the stack guide 38 
at 60 percent compression loss provides a margin of error in the event the 
need for retorquing is not timely detected. 
The liveload assembly 12 is particularly suited for installation on valves 
and pumps used in nuclear plants. The assembly readily fits on existing 
bolts securing the gland follower to the stuffing box. Generally, the 
gland bolt does not have to be replaced with a longer bolt as may be the 
case when uncompressed belleville washers are positioned over the bolt. 
Further, the liveload assembly 12 of the present invention may be installed 
more quickly on valves and pumps than previous methods of installing 
belleville washers. Installation and compression of belleville washers on 
a valve or pump may take as much as one hour or more to position the 
belleville washers and to compress them to the proper specified load using 
torque wrenches. Installation of the liveload assembly 12 according to the 
present invention however is direct, rapid and trouble free. Significant 
time and labor cost savings may be gained by using the assembly 12. 
Further, the packing in properly loaded valves and pumps has a 
significantly longer life than packing in valves and pumps without 
liveloading. 
The principles, preferred embodiments and modes of operation of the present 
invention have been described in the foregoing specification. The 
invention is not to be construed as limited to the particular forms 
disclosed, because these are regarded as illustrious rather than 
restrictive. Moreover, variations and changes may be made by those skilled 
in the art without departing from the spirit of the invention as set forth 
by the following claims.