Flow volume detection device

The present invention is directed to an apparatus and method for monitoring the continued rotation of a non-magnetically attractive indicator, e.g., a rotating, plastic dial, disc, wheel, arm or the like of a meter. The present invention is particularly useful for detecting the satisfactory operation of flow meters, e.g., meters used to determine the flow of fluids from oil and gas wells, in transmission lines and in chemical processing plants. The present invention provides a system for monitoring the operation or rotation by employing a rotating, magnetically attractive actuator to actuate a magnetic switch which in turn actuates an electrical switch for producing a monitoring signal. The apparatus and method of the present invention provide a rigid, dependable, accurate and wear-free device for monitoring the continued operation of a flow or other meter.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention generally relates to an apparatus and method for 
monitoring the continued rotation of a non-magnetically attractive 
indicator, e.g., a rotating, plastic dial, disc, wheel or arm of a meter. 
The present invention is particularly useful for detecting the 
satisfactory operation of flow meters, e.g., meters used to determine the 
flow of fluids from oil and gas wells, in transmission lines and in 
chemical processing plants. More particularly, the present invention 
relates to an apparatus and method employing the rotation of a 
magnetically attractive material for actuating magnetic and electrical 
switches for producing signals indicative of satisfactory operation of the 
flow meter. 
2. Description of the Background 
The desirability of observing and controlling the flow of a fluid through a 
conduit from a great distance has long been recognized by those associated 
with the oil and gas, the fluid transmission and the chemical processing 
industries. These observations would permit operators and controllers to 
more closely monitor flow and to more quickly react to deviations and 
malfunctions. 
For example, it is important to have an accurate record of the fluid being 
pumped from remote oil and gas wells. Typical recording systems include 
conventional flow detection and volume devices interconnected with 
conventional rotating dial meters. These meters comprise a plurality of 
geared dials for displaying a number indicative of the volume of fluid 
passing through the conduit. In order to avoid the loss of production or 
lost/inaccurate measurement of production, it is desirable to have a means 
for a centrally located controller to observe the operation of these 
meters. Such observation permits immediate shut down of any well showing 
abnormal production and immediate dispatch of a repair crew. This 
immediate reaction is quite valuable to the oil and gas producer. 
Conventional monitoring systems have included an electrical switch actuated 
by the meter movement to produce a signal at the central location. This 
signal has been used to actuate a variety of functions, including 
actuating a central counter, actuating a sampling device in the conduit 
near the meter and resetting an alarm device. The alarm is often a simple 
timer which must be reset within a predetermined time indicative of 
satisfactory operation of the meter showing the expected fluid flow. 
Failure of the signal to reset the alarm within the predetermined flow 
indicates an abnormal condition and will trigger shut down of the well 
pump and visual and/or audio alarms. Exemplary conventional systems have 
employed a cam on the meter shaft to operate a plunger or to operate a 
spring loaded lever to produce the necessary electrical output. These 
systems produce drag on the meter mechanism and contain rubbing parts 
which wear out. More recently, systems have been developed which 
incorporate a reed switch actuated by a magnet disposed on the rotating 
dial of the meter. These systems are plagued by the extreme fragility of 
the reed switch, particularly in view of the harsh environment and rough 
handling to which these devices are typically subjected. Further, the 
magnet rotating in a predominantly steel environment also produces drag on 
the meter. 
Accordingly, there has been a long felt but unfulfilled need within the 
industry for a rigid, dependable and accurate apparatus and method useful 
for monitoring the continued rotation of a meter dial. 
SUMMARY OF THE INVENTION 
The present invention provides a new and improved apparatus and method for 
monitoring the continued rotation of a non-magnetically attractive 
indicator and particularly useful for monitoring the continued operation 
of flow meters and the like. The apparatus and method of the present 
invention are useful together with volume detection devices, automatic 
sampling devices, and alarm devices for detecting pump or meter 
abnormalities and for stopping the fluid flow. 
In a simple embodiment of the present invention, an actuating means 
comprised of a magnetically attractive material disposed about a small arc 
of the periphery of the rotating indicator is employed to actuate a 
magnetic switching means disposed near the disc and actuated by the 
proximity of the actuating means. An electrical switching means for 
producing an output indicative of the rotation of the indicator is then 
actuated by the magnetic switching means. A ferrous material, e.g., an 
iron plug, is preferred as the actuating means although any magnetically 
attractive material producing the necessary force of magnetic attraction 
is sufficient. Even another magnet may be used as the actuating means to 
increase the actuating proximity although use of another magnet 
counteracts at least one of the advantages of the present invention. 
The attractive force developed between the actuating means and the movable 
magnet of the magnetic switching means must be sufficient to overcome the 
force of a biasing means normally biasing the switching means to a first 
position. When a sufficient attractive force is developed by bringing said 
actuating means and said magnetic switching means into actuating 
proximity, the magnetic switch and the electrical switch are both actuated 
to a second position. Preferably, the biasing means comprises a plurality 
of magnets acting together with the movable magnet in the magnetic 
switching means. 
A monitoring system in accord with the present invention as briefly 
described above is useful to supply an actuating electrical signal to a 
variety of other systems. For example, the produced electrical signal is 
useful to actuate an automatic sampling device to periodically sample the 
fluid flowing in the conduit near the meter. Further, the produced 
electrical signal is useful to trip a remote volume or flow monitor. 
Another useful application of the produced signal is to reset an alarm 
which is used to monitor fluid flow. Failure to reset such an alarm within 
a predetermined time indicative of expected normal operating conditions 
may result in activation of visual or audio alarms or in activation of a 
system to stop the fluid flow in the conduit near the meter. 
A system in accord with the present invention provides a rigid, dependable, 
accurate and wear-free apparatus useful in a method for monitoring the 
continued operation of a fluid flow meter or the like, including a 
rotating, non-magnetically attractive indicator. Such a device produces no 
significant drag on the meter, includes no wearing parts and requires no 
maintenance. These and other meritorious features and advantages of the 
present invention will be more fully appreciated from the following 
detailed description and claims.

While the invention will be described in connection with the presently 
preferred embodiment, it will be understood that it is not intended to 
limit the invention to this embodiment. On the contrary, it is intended to 
cover all alternatives, modifications and equivalents as may be included 
in the spirit of the invention as defined in the appended claims. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The present invention is directed to an apparatus and method useful for 
monitoring the continued rotation of a non-magnetically attractive 
indicator, particularly the satisfactory operation of a flow meter or the 
like. 
An apparatus 10 in accord with the present invention is schematically 
illustrated in FIG. 1. A pump 22 propels a fluid, e.g., the well fluids 
from a remote oil well, through a conduit 20. It is necessary and 
desirable to monitor and to record the volume of fluid flowing through the 
conduit 20. Accordingly, a means for converting the fluid flow to a 
measurable rotary motion is suspended within the conduit. For example, a 
propeller 24, series of vanes or other conventional device is suspended 
within the conduit 20. The rotary motion of the propeller 24 is 
transmitted and converted by appropriate gears 26 to a flow volume display 
meter 28. Within the display meter 28, the rotary motion is converted by 
conventional gears and the like for numerical display on a series of 
dials. For example, a plurality of appropriately geared plastic discs 42 
having visually readable numbers disposed on the periphery thereof provide 
a conventional digital readout. 
The system of the present invention is preferably adapted for use with a 
rotating indicator 42 comprised of a non-magnetically attractive material. 
For example, the indicator 42 may comprise a plastic, aluminum, stainless 
steel or wooden rotating disc, wheel, dial or arm. Disposed about a small 
arc of the periphery of the rotating indicator 42 is an actuating means 
comprising a magnetically attractive material. For example, a ferrous or 
iron plug 40 disposed within the center of the digit "0" provides the 
preferred actuating means. However, in an alternative embodiment, a magnet 
is employed as plug 40 in order to increase the distance through which the 
magnetic switch 50 is actuated. 
An exemplary magnetic switch 50 and electrical switch 80 are schematically 
illustrated in FIGS. 2 and 3. The exemplary magnetic switch 50 comprises a 
housing having a cylindrical side 52 and end cap 56 of a non-magnetically 
attractive material, e.g., stainless steel. An annular magnet 60 is 
disposed within the cylindrical housing 52 near the end cap 56 to provide 
a biasing means. A second annular magnet 58 is disposed within the 
cylindrical housing 52 adjacent the biasing magnet 60. A tab or ring 54 
maintains the magnets 60 and 58 in fixed positions. The primary or movable 
magnet 70 is preferably a cylindrical magnet designed to slidably fit 
within the central bore 62 through the annular magnets 60 and 58. The 
poles of the fixed magnets 60, 58 and the movable magnet 70 when arranged 
as illustrated in FIGS. 2 and 3 act to maintain the movable magnet 70 in 
the position illustrated in FIG. 2 in the absence of a magnetically 
attractive actuating means in proximity with the end cap 56. In the 
illustrative example of FIG. 2, the biasing magnet 60 repels and the 
center magnet 58 attracts the movable magnet 70 to the illustrated 
position. 
FIG. 3 illustrates the same magnetic switch 50 wherein an actuating means 
40 disposed in a non-magnetically attractive indicator 42 has been brought 
within actuating proximity of the end cap 56 causing the movable magnet 70 
to be attracted toward the actuating means 40. Those skilled in the art 
will be aware that the force of attraction between the actuating means 40 
and the movable magnet 70 must be sufficient to overcome the biasing force 
developed by the fixed magnets 60, 58 or other biasing means, e.g., a weak 
spring to normally maintain the movable magnet in the position illustrated 
in FIG. 2. Those skilled in the art will appreciate that the strength of 
the magnets 70, 60, 58, the size of the actuating means 40 and the 
necessary proximity for actuation are readily adjusted to produce the 
desired system. 
Movement of the movable magnet 70 of the magnetic switch 50 causes movement 
of an electrical switch, e.g., single pole double throw switch (SPDT) 80. 
The movable magnet 70 is connected to the electrical switch as by a 
mechanical linkage 72. In the absence of an actuating means 40 within 
actuating proximity of the magnetic switch 50, the SPDT switch 80 
completes a circuit from the lead 74 through the lead 76 as illustrated in 
FIG. 2. When an actuating means 40 has been brought within actuating 
proximity of the magnetic switch 50, the SPDT switch 80 completes a 
circuit from the lead 74 through the lead 78. 
A monitoring system in accord with the present invention is useful for many 
applications, several of which are illustrated in FIG. 1. The actuation of 
the magnetic switch 50 by the actuating means 40 upon each revolution of 
the wheel 42 of the display meter 28 sends an electrical signal along the 
lead 78 to a relay 30. This signal conveniently is employed to actuate a 
conventional fluid sampling device 32 useful for producing a composite 
sample of the fluid passing through the conduit 20. Another use for this 
signal is to advance a digital, computer or other readout device 34 
conveniently located at a central location distant from the flow meter. 
Still another use for this signal is to reset a timer of an alarm device 
36. A conventional alarm includes a timer having a visual and/or audio 
alarm and typically a means to stop the fluid flow, e.g., a motor shut 
down switch 38 to stop the pump motor 22. The device 36 is typically 
programmed to activate the alarm signals upon expiration of a 
predetermined time interval sufficient to define one revolution of the 
actuator means 40 in the absence of a malfunction or abnormality. 
Accordingly, resetting of the timer of the alarm device 36 in response to 
the electrical signal in the lead 78 indicates continued satisfactory flow 
in the conduit 20 and operation of the meter 28. 
The foregoing description of the invention has been directed in primary 
part to a particular preferred embodiment and method in accordance with 
the requirements of the patent statutes and for purposes of explanation 
and illustration. It will be apparent, however, to those skilled in the 
art that many modifications and changes in the specifically described 
apparatus and method may be made without departing from the scope and 
spirit of the invention. For example, Applicant has illustrated and 
described a device and method employing an iron plug as the actuating 
means. However, those skilled in the art will appreciate that any material 
which will attract the movable magnet of the magnetic switch with 
sufficient force to overcome the biasing force and to actuate the 
electrical switch may be used as the actuating means. Therefore, the 
invention is not restricted to the particular form of construction and 
method illustrated and described, but covers all modifications which may 
fall within the scope of the following claims. 
It is Applicant's intention in the following claims to cover such 
modifications and variations as fall within the true spirit and scope of 
the invention.