Fiber sampling device

A device for obtaining a sample of fiber from an aqueous slurry of fiber flowing through a stock line, comprising a first isolation inlet valve element together with a water supply orifice, located inside a fiber stock line; a second isolation valve means, and a third isolation valve, mounted in flow series from the sample inlet point on the stock line. This device allows a complete water purging down through the inlet valve element, as well as fiber samples to flow out of the stock line in the presence of diluent water. Samples flow from the first isolation valve means to a final collection point, without contamination or plugging.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an improved device for obtaining a sample 
of fiber from a fiber processing plant, such as a pulp or paper mill, a 
corn plant, or a starch plant. The improved fiber sampling device has 
several advantages over current sampling devices, including the ability to 
fully flush, in order to remove residual fiber, and the ability to be 
installed and removed while the plant is running. The improved fiber 
sampling device, therefore, allows fiber processing plants to obtain 
useful samples more easily and with less contamination than with current 
sampling units. 
2. Brief Description of the Prior Art 
A large number of industries are based on the processing of natural fiber. 
The pulp and paper industry, for example, converts wood fiber to pulp and 
paper products. The corn processing industry converts corn to starch, 
sugar, corn oil, and other products. Other crops, such as wheat and 
soybeans, are processed in an analogous manner. Cotton fiber is processed 
to make clothing and other textile goods. 
One need that this wide range of industries has in common is the need for 
fiber sampling. All of the fiber processes are run at specified conditions 
(temperature, pH, salt concentration, etc.) and are run to a given degree 
of processing (chemical reaction, purity, removal of inhibitors, etc.). 
Although a good deal of automated instrumentation is available to monitor 
and control these process variables, in almost all plants there are some 
process variables that are not controlled automatically, and samples of 
the fiber are required for process control. In addition, most automated 
controls require occasional (or frequent) calibration with actual samples. 
Much sampling of fiber is carried out manually. Manual fiber sampling 
consists of grabbing a sample of fiber with one's hands or with a scoop, 
where the fiber is openly exposed. If the fiber is flowing within a stock 
line, a manual sample can be taken by opening a valve attached to the line 
and using the pressure in the line to force the sample out. The sample is 
collected until the desired quantity is obtained, and the valve is then 
closed. 
A more sophisticated form of manual sampling consists of two valves in 
series, connected by an intermediate pipe that is 6 to 12 inches long. The 
valve closer to the stock line, hereinafter referred to as the first 
isolation valve, is opened and closed to take a sample; the valve farther 
from the stock line, hereinafter referred to as the second isolation 
valve, is closed except when removing a sample from the pipe. To take a 
sample, the first valve is opened to fill the intermediate pipe with 
fiber. The first valve is then closed, and the second valve is opened to 
allow removal of the fiber sample. 
An advantageous variant of the two-valves in series is to add a third valve 
to the system, which is attached to a T coming off the intermediate pipe. 
This third valve can be opened to allow water into the intermediate pipe, 
and force the fiber sample out when the second isolation valve is open. 
Such a known three-valve sampler can be installed on-line, that is, while 
the plant is running, and fiber is flowing through the stock line under 
pressure. This is advantageous, as it avoids the need to shut down the 
mill to install the sampler. On-line installation is carried out using a 
so-called hot-tap procedure. A first valve is connected to one end of a 
pipe nipple, the other end of the nipple then is welded to a stock line. A 
hot tap apparatus is attached to the other part of the first valve. The 
valve is opened; a drill bit is pushed through the opening within the 
valve body; until it bores through the wall of the stock line. The drill 
bit then is removed through the valve body and the first valve is closed. 
A first valve so attached to the stock line then is ready to be attached 
to an intermediate pipe and a second valve. 
There are several disadvantages associated with known three valve systems. 
First, there is no water flush between the first valve and the stock line, 
and fiber can build up at this point, and contaminate subsequent samples. 
Second, there is no technique to remove the entire system on-line, for 
cleaning or maintenance. 
While operation of known three valve samples can be automated, so as to 
allow the samples to be taken automatically, such automation does not 
overcome the inherent disadvantages of the unit during automatic sampling. 
For frequent or multiple samples, and for situations where a sample must be 
moved a large distance for analysis, certain automated sampling units are 
known. Several known commercial sampling devices are listed in Table 1. 
These devices are used for specific solids consistencies, pipe diameters, 
process temperatures, and materials of construction. In each device a 
sample is conveyed to a desired location or instrument by either: 
1. Internal pressure in the stock line, which feeds the sample directly to 
the instrument a short distance away. 
2. A piston-type pressure, where a moving piston conveys a sample of fiber 
a distance of 50-200 feet. 
3. A flowing-type, where water conveys the sample to the instrument. 
A typical example of such devices, is the Kajaani SD-503, which contains a 
sampling valve element that is inserted into the stock line, and is 
electrically actuated from outside the stock line. The tip of the sampling 
valve is a plunger that opens and closes to admit a sample. This sampling 
valve is short (with a length less than two inches), and has an inlet port 
coupled to the stock line by a process coupling. The outlet part of the 
sampling valve is attached to a sample chamber. The pulp samples pass 
through a sample chamber and out of a hose, to a remote location. Water is 
admitted to the sampling chamber, at a point just downstream from the 
process coupling. This water is used to convey the samples out of the 
sample chamber, and into the hose. 
One shortcoming of the SD-503 sampling device is the inability to do a 
complete water flushing of the sample chamber. The system is not designed 
for flush water to penetrate all the way to the sampling valve element. In 
addition, crevices within the sample chamber catch and hold fiber. This 
makes fiber buildup at or near the isolation valve likely, which causes 
cross contamination of samples. Another shortcoming of the SD-503 sampling 
device is that it cannot be installed or removed on-line. The requirement 
to shut down the plant or fiber line before installing or removing the 
sampling valve element is a serious inconvenience, and cost factor. 
TABLE 1 
______________________________________ 
AUTOMATIC SAMPLING DEVICES 
MANU- SOLIDS PIPE SPECIAL 
FACTURER 
UNIT CONSISTENCY DIAMETER 
FEATURES 
______________________________________ 
ABB 1000 &lt;6% not specified 
EPDM seal 
1001 &lt;6% not specified 
Viton seal 
1002 &lt;6% not specified 
Screens sample 
1003 6-14% not specified 
EPDM seal 
1004 6-14% not specified 
Screens pulp 
MCB- 6-14% not specified 
Screens pulp 
1003 
BTG HDS- &gt;12% not specified 
temp &gt;150 C. 
1010 
HDS- &gt;12% not specified 
temp &gt;150 C. 
1100 
MDS- 5-12% not specified 
1100 
LDS- &lt;5% not specified 
1100 
KAJAANI SD-501 6-15% not specified 
piston type 
SD-502 0.5-6% &lt;8 inches 
flow type 
SD-503 0.5-6% &lt;4 inches 
titanium 
______________________________________ 
Therefore, in spite of the availability of a wide variety of fiber 
samplers, there are significant shortcomings with such known devices. 
Those shortcomings are addressed by the present invention. 
SUMMARY OF THE INVENTION 
The inventor has developed a device for sampling fiber automatically that 
can be completely flushed to avoid fiber buildup, and that also can be 
installed and removed on-line. The invention enables operators of fiber 
processing plants to obtain samples more conveniently and without 
cross-contamination from previous samples. Hence, the present invention 
results in better quality samples, with less effort and lower maintenance. 
A unique aspect of the fiber sampler taught herein is a first isolation 
valve and sample chamber with a water flushing configuration that enables 
both to be completely flushed with water, thereby eliminating cross 
contamination of fiber samples. In a preferred embodiment, the fiber 
sampler valve element can be inserted through a valve and into a stock 
line for on-line installation and removal.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
FIG. 1 illustrates a preferred embodiment in use, wherein an automated 
sampling device has been mounted upon a fiber stock line. The device 
essentially comprises a fiber sampler valve element 5 located within the 
stock line, and controlled by a linear actuator 1. Valve 5 is the first, 
or primary isolation means controlling the flow of fiber within and out 
the sampler. The actuator 1 is a pneumatic solenoid that acts linearly 
upon the first, or sampler valve element 5 through a hollow tube 9, in 
order to open and close valve element 5 against a conical or spherical 
seat, in the fashion of a tappet valve. A second, or secondary isolation 
valve in this embodiment preferably is a ball valve 4, through which an 
entire tubular sample chamber 3 may be inserted. Valve 4 is open unless 
the sampler is being removed. This embodiment also includes a third, or 
tertiary remote isolation valve 7, as well as liquid inlet ports 2 and 6, 
to regulate the flow of water into the system. Liquid port 2 is connected 
to a high pressure water main line, by a conventional valve (not shown). 
A sampling cycle may starts with an initial fiber purge, wherein valve 7 is 
closed and actuator 1 through hollow tube 9 opens the sampler valve 
element 5. Water or other cleaning liquid can be forced through inlet 
ports 2 and 6, to respectively flow outside and inside the hollow tube 9, 
through openings located at the base of hollow tube 9 down past sampler 
valve element 5 and into stock line 8. This flushing configuration passes 
water through the entire sample chamber 3, both inside and outside 
actuator tube 9, within tubular chamber 3. The chamber and tube geometry 
illustrated in FIG. 1 is defined by smooth and clear surfaces, to 
eliminate any sharp crevices where fiber will accumulate. By this, or 
another type of flushing actions, as described hereafter, there is a purge 
which completely removes residual fiber from the sampler device, thereby 
preventing contamination of subsequent samples. 
When an initial fiber purge is complete, actuator 1 is set to leave sampler 
valve element 5 opened; third isolation valve 7 is opened; and the water 
source into liquid inlet port 2 is closed, so as to depressurize entire 
the sampler. Internal pressure inside stock line 8 forces stock fiber 
through valve element 5 and into tubular sample chamber 3, and 
specifically into an annulus defined outside actuator tube 9. The fiber 
sample then is transported up tube 3 towards third isolation valve 7. 
When sufficient fiber sample is collected, the actuator 1 closes first 
valve element 5, and high pressure water from a main water line, is 
admitted at liquid inlet port 2. The sample then is transported downstream 
past third valve 7, by water flowing from inlet port 2. 
A reverse, or backflushing, type of initial purge may not always be needed. 
When sufficient fiber has been collected, diluent water from inlet port 6 
can simultaneously be forced to flow down tube 9 towards closed valve 
element 5, through openings located at the base of actuator tube 9 in 
close proximity to valve element 5, and then back up the outside annulus 
of tube 9. This action then will act as an important, second purge in 
order to remove stray fiber from the sample chamber. When a sample reaches 
its destination, and both valve 5 and the third isolation valve 7 are 
closed, then water pressure inside sample chamber 3 can be allowed to rise 
above the internal pressure in the stock line 8, and be in readiness for 
another initial purge. A cycling of valves 1 and 7 to so adjust pressure 
inside the sample chamber 3 can be controlled conventionally by an 
external timer circuit or computer (not shown), in a conventional manner. 
A stock sample first is diluted with water, at or near to the sample valve 
element 5 through openings located at the base of actuator tube 9. Diluent 
water can be added through inlet port 2, from a high pressure, main water 
line, while a sample is being taken from the stock line. In a most 
preferred embodiment, as illustrated in FIG. 1, the stock is diluted with 
water entering inlet port 6, from a low pressure water line, with diluent 
water traveling inside and down actuator tube 9, and is admitted to the 
stock sample at or near valve element 5. A typical dilution (expressed as 
weight water:weight stock) is about 10:1, but this ratio can be varied 
widely by pulsing the dilution water source or varying the dilution water 
pressure relative to the stock pressure. Such controlled dilution at the 
sample valve element advantageously allows sampling of slurries with 
higher fiber consistency. Existing automatic sampling devices that use 
water to convey a fiber sample do not dilute the sample at the initial 
point of sampling, but rather at an instrument or other remote location. 
Such remote dilution increases the possibility of plugging the sample line 
near the stock line. 
Installation of a secondary isolation valve 4 can be carried out on-line 
using a hot-tap procedure, as described above. Once ball-type valve 
element inside valve 4 is opened, a distal end of tubular chamber 3 and 
tube 9 (with valve element 5) is inserted downwardly therethrough, and the 
proximate end of the tube is connected directly to a linear actuator 
connector on the solenoid actuator 1. The sampler unit is then operated 
with ball valve 4 always open. 
The sampler assembly is removed from the stock line, for cleaning or 
maintenance, by raising the distal end of tubular chamber 3 and tube 9 up 
through secondary isolation valve 4, and then closing that valve. Then the 
upper assembly is removed from the threaded nipple connection shown just 
above valve 4. This does not disrupt the flow or pressure in the stock 
line. 
For best operation, the cylindrical opening in the ball valve element of 
secondary isolation valve 4 maintains a leak-tight seal against the 
outside of the tubular sample chamber 3. This arrangement is 
self-centering and self-correcting for any wear or damage due to sand 
inside the fiber line. 
In essence, the tubular sample chamber 3 is designed to allow the water 
flush to completely remove fiber from inside that chamber. This is 
accomplished by allowing the water flush an unimpeded flow out of the 
chamber, and locating the flow such that it is unidirectional and not 
encumbered with twists, turns, stagnant zones, or other configurations 
that catch or hold fiber or result in incomplete fiber removal. In the 
embodiment illustrated by FIG. 1, the sample chamber consists of the 
annulus between concentric, cylindrical tubes, with tube 9 an inner 
cylinder and chamber 3 an outer cylinder. The water flush is carried out 
by flowing water out of both tube 9 and the annulus outside tube 9. There 
is no other space within the sample chamber for fiber to accumulate. 
It will be recognized by those skilled in the art that several alternate 
designs are possible, including but not limited to the inner cylinder 
located off-center to the outer cylinder, or the presence of more than one 
inner cylinder, or conduits of non-cylindrical shapes. 
In the preferred embodiment, the fiber sample flows in the annulus between 
the coaxial cylinders. It will be recognized by those skilled in the art 
that several alternate designs are possible, including fiber flowing 
within the inner cylinder. 
In the preferred embodiment of FIG. 1, the entire sample chamber is 
inserted slidably within a cylindrical passage in a ball valve element. 
This allows the chamber to be installed or removed on-line. The minimum 
length of such a sample chamber (3) to insert through a valve and protrude 
into the stock line is about 4 inches. A preferred length is about 8 to 18 
inches. Sample chambers longer than this length are difficult to flush 
completely. The maximum practical size of chamber 3 at the point which 
passes through the ball valve 4 is an outer diameter of about 1.5 inches. 
If the diameter is larger than this, the force required to manually 
install and remove the device, which must overcome the pressure force of 
the stock line, is too great. A more preferred outer diameter of the 
sample chamber is less than about 0.75 inches. 
Primary isolation valve means (5) can in practice be any means of isolating 
the fiber sample from the stock line and opening and closing to admit 
samples. Several embodiments familiar to those skilled in the art are 
conical seat valves, flanges, diaphragms, and couplings. 
The primary isolation valve means can be actuated by a pneumatic actuator, 
an electric actuator, or other device familiar to those skilled in the 
art. The actuator is located outside of the fiber source, in contrast to 
valve 5, which is located within the fiber source. In the preferred 
embodiment shown in FIG. 1, valve element 5 is actuated pneumatically. In 
the preferred embodiment, actuator 1 is a pneumatic solenoid. 
The secondary isolation valve means can be any valve or similar device 
familiar to those skilled in the art, that permits the passage of a tube 3 
through a valve opening. Some examples of this are ball valves, gate 
valves, butterfly valves, and diaphragm valves. In a preferred embodiment, 
a ball valve is used, wherein the opening of the valve is straight to 
allow the insertion of the main sampler tube. In a preferred embodiment, 
the valve also has threaded inlet and outlet ports. In a most preferred 
embodiment shown in FIG. 1, the valve 4 is a threaded ball valve. 
The tertiary isolation valve means can be any valve or similar device 
familiar to those skilled in the art, which permits the passage of fiber 
slurry when opened, including a ball valve, gate valve, diaphragm valve, 
butterfly valve, or other valve device. In a preferred embodiment shown in 
FIG. 1, a sanitary diaphragm valve is used to allow for rapid opening and 
closing. 
Transport water inlet means, connected to high pressure water, can employ 
any valve or similar device familiar to those skilled in the art, that is 
used to control the flow of water. In a preferred embodiment, liquid inlet 
port 2 includes a nearby solenoid valve. In a most preferred embodiment 
shown in FIG. 1, a valve proximate inlet 2 is a solenoid diaphragm valve. 
Diluent water inlet means, connected to a smaller water line, can employ 
any valve or similar device familiar to those skilled in the art, that is 
used to control the flow of water. In a preferred embodiment, liquid inlet 
port 6 includes a nearby solenoid valve. In a most preferred embodiment 
shown in FIG. 1, a valve proximate inlet 6 is electric solenoid diaphragm 
valve. 
The fiber sampler parts can be manufactured using stainless steel, other 
metals, or plastics compatible with the chemicals present in the materials 
being sampled. In a preferred embodiment, the body of fiber sampler is 
made using titanium. 
While the embodiment illustrated in FIG. 1 shows the sampler mounted to a 
source of fiber that is a fiber stock line, any pressurized containment, 
such as a surge tank, is equivalent to the illustrated section of stock 
line. In practice, the sampler can be mounted to any aqueous fiber slurry 
containment that is under at least 0.5 psig pressure, to force the sample 
into the sampler unit. Such containments include but are not limited to 
hold tanks, surge tanks, and stock lines. 
While a preferred embodiment has been shown and described, the invention is 
to defined solely by the scope of the appended claims.