Electric motor driven pump with an automatic transmission

A pumping system includes a pump for pumping a liquid, a motor for driving the pump, and components for coupling the pump to the motor so that the speed at which the pump is driven varies automatically according to the load the liquid imposes. One embodiment employs an automotive fluid transmission with a torque converter for this purpose, along with input and output manifolds that enable connection to differently sized lines. These components may be mounted on a portable support structure, such as a cart, to form a fully automatic, portable pumping system arranged so that a user can manually move the system to a desired location, connect to variously sized lines, and pump any of various liquids having different or varying viscosities.

BACKGROUND OF THE INVENTION 
1. Technical Field 
This invention relates generally to pumps, and more particularly to a 
pumping system designed to better accommodate varying loads. 
2. Background Information 
One problem encountered with some pumping systems, such as a conventional 
gear pump driven by a constant speed electric motor, occurs when pumping 
liquids having different or varying viscosities, such as epoxy, lacquer, 
paint thinner, syrup, and the like. Not only do the viscosities of such 
liquids differ from each other, but the viscosity of any one may vary 
significantly with various changing conditions such as temperature. In 
addition, it may be desirable to pump the liquid through differently sized 
lines and this causes load variations as well. As a consequence, the 
pumping system must be designed to accommodate the varying load that can 
result because a system failure may have catastrophic consequences if it 
occurs when pumping a liquid such as epoxy that can quickly solidify in 
the pump and conduits. 
To guard against that happening, some existing systems utilize a motor of 
sufficient size to handle the greatest load anticipated (i.e., that 
accompanying the greatest viscosity and smallest conduit or line 
expected). However, processing speed is then restricted to that which is 
safe under such worst case conditions so that in addition to such a 
technique being costly in terms of hardware, it is inefficient in terms of 
processing speed. Consequently, it is desirable to have a pumping system 
that alleviates these concerns. 
A related problem occurs when the flow of liquid out of the pumping system 
is turned on and off, such as may occur in the normal course of such 
activates as packaging. Turning the flow of liquid off, for example, can 
cause an abrupt increase in the load and pressure. This only compounds the 
varying-load problem caused by different and varying viscosities. 
Some existing systems avoid this problem by either simultaneously turning 
the motor on and off or by switching in a bypass arrangement that provides 
a path from the pumping system outlet back to the inlet. However, turning 
the motor on and off can be inconvenient and decrease processing speed, 
Furthermore, it can involve high starting currents each time the electric 
motor is turned back on. The use of a bypass arrangement also results in 
significant current fluctuations, a high pressure head tending to build up 
during bypass and a fluid surge occurring when the system outlet is opened 
again. Thus, it is desirable to have a system that alleviates these 
concerns also. 
SUMMARY OF THE INVENTION 
This invention solves the problems outlined above with a pumping system 
having an automatic transmission between the pump and the motor that can 
automatically downshift as the load increases. Thus, it enables automatic 
adjustment to the load, pressure, hose size, and viscosity. It relieves 
worst case motor size requirements. It maintains the best processing speed 
automatically. It simplifies start-stop operations. It avoids current and 
pressure surges, and it allows the motor to continue running at full speed 
after the pump has slowed significantly or even stopped. 
Generally, a system constructed according to a major aspect of the 
invention includes a pump for pumping a liquid, a motor for driving the 
pump, and components for coupling the pump to the motor so that the speed 
at which the pump is driven varies automatically according to the load the 
liquid imposes. These components may include an automatic transmission 
operatively connected between the motor and the pump, such as a slightly 
modified, automotive-type fluid transmission, and the automatic 
transmission may include a torque converter so that the motor can continue 
running at substantially full speed regardless of how slow the pump is 
operating. 
According to another aspect of the invention, there is provided a portable 
pumping system that includes a pump, motor, and automatic transmission 
mounted on a portable support structure, such as a cart. These are 
accompanied by input and output manifolds that can be connected to 
differently sized lines and a control box with which a user can control 
operation of the motor and the automatic transmission. This arrangement 
enables a user to move the pumping system to a desired location, connect 
to variously sized lines, and pump any of various liquids having different 
or varying viscosities. It does not discriminate against hose size and 
multiple hose connections, and it eliminates the need for specific pump 
sizes. 
In line with the above, a method of accommodating varying loads when 
pumping a liquid with a motor-driven pump includes the step of interposing 
an automatic transmission between the pump and a motor driving the pump in 
order to couple the pump to the motor so that the speed at which the pump 
is driven varies automatically according to the load. Although it is known 
to use a variable speed drive between a pump and a motor, this invention 
utilizes an automatic transmission that can downshift and upshift 
automatically in response to increases and decreases in the load. In so 
doing, it solves the problems discussed above while maintaining maximum 
flow under varying load conditions for a given horsepower motor, and the 
torque converter provides circuit protection and anti-surge operation as 
well as allowing the pump to slow to a complete stop. 
The above mentioned and other objects and features of this invention and 
the manner of attaining them will become apparent, and the invention 
itself will be best understood, by reference to the following description 
taken in conjunction with the accompanying illustrative drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIG. 1, there is shown a diagrammatic representation of a 
pumping system 10 constructed according to the invention. The system 10 is 
being utilized to pump a liquid, such as syrup, from a holding vat 11 to a 
semitrailer tank 12. Of course, it can be used to pump other liquids from 
any of various sources to any of various destinations, but it does so in a 
manner subsequently described that better accommodates varying loads 
imposed by the liquid. 
Generally, the system 10 includes a pump 13 for pumping a liquid, a motor 
14 for driving the pump 13, and a transmission 15 for coupling the pump 13 
to the motor 14. The coupling is done according to a major aspect of the 
invention so that the speed at which the pump 13 is driven varies 
automatically according to the load the liquid imposes. This enables the 
system 10 to better accommodate varying loads and pressures. 
The pump 13 may take the form of any of various known pumps, such as a 
three-inch, positive displacement, gear pump that operates conventionally 
by rotation of a shaft 16 to pump liquid communicated to a three-inch 
inlet 17 of the pump 13 out of a three-inch outlet 18 of the pump 13. The 
motor 14 may take the form of any of various known sources of rotary 
power, such as a 7 1/2 horsepower, 1725 rpm, electric motor that operates 
on 110, 220, or 440 volts, for example, or a gasoline engine or any other 
means of driving the transmission. The motor 14 is powered by electric 
current coupled from a separate source (not shown) through a line 19, 
control box 20, and line 21, this being done in a suitable known way so 
that a user can control operation of the motor 14 (turn it on and off) 
from the control box 20. 
The transmission 15 may take the form of any of various known automatic 
transmissions that can downshift or upshift automatically as the load or 
pressure increases or decreases (i.e., the ratio of output speed to input 
speed automatically decreases as the load increases and vice versa as the 
load decreases). In other words, the input of the transmission 15 is 
coupled by a shaft 22 to the motor 14 and the output of the transmission 
15 is coupled by the shaft 16 to the pump. As the load presented to the 
transmission 15 by the shaft 16 increases beyond a predetermined value, 
the transmission 15 automatically shifts to a lower ratio so that the 
shaft 16 rotates more slowly for the same speed of the motor 14. 
Similarly, the transmission 15 can shift to a higher ratio when the load 
decreases. 
In that regard, the transmission 15 is a commercially available 
automotive-type transmission, such as the transmission available from 
General Motors having the product name TURBO HYDRO 250. It has three 
forward speed ranges that may be designated HIGH, SECOND, and FIRST. For 
an input speed of 1725 rpm, HIGH results in an output speed of about 
800-1725 rpm, SECOND results in an output speed of about 350-800 rpm, and 
FIRST results in an output speed of about 0-350 rpm. 
The transmission 15 also includes a NEUTRAL position and a REVERSE speed 
range which results in the output rotating in a direction opposite to that 
of the above three speed ranges (at 0-350 rpm for an input speed of 1725 
rpm) so that the flow of liquid can be reversed if desired. In addition, 
the transmission 15 includes a torque converter 23 that operates 
conventionally so that the motor 14 can continue to operate at 
substantially full speed regardless of how slow the pump 13 and shaft 16 
rotate. In other words, the torque converter 23 serves as means for 
enabling the motor to continue running at substantially full speed 
regardless of how slow the pump is operating, and it protects against 
surges when the flow of liquid is turned on and off. Of course, various 
other types of automatic transmission may be used as long as they can 
automatically decrease the ratio of the output speed to the input speed 
when the load increases. 
The transmission 15 is operatively connected between the pump 13 and the 
motor 14. It is connected to the shaft 16 of the pump 13 by known suitable 
means, such as a chain coupler, and to the motor 14 by suitable known 
means, such as a pulley system with a flywheel adapter arrangement. This 
couples the pump 13 to the motor 14 with the transmission 15 where many 
prior art pumping systems use a gear train. 
A quarter-inch shift cable or control cable 24 extends from the 
transmission 15 to the control box 20. It operates conventionally to 
enable a user to select a desired range of the transmission. It is 
suitably connected according to known techniques to the control box 20 so 
that a user can control operation of the transmission 15 (select a desired 
range) from the control box 20. In other words, the user operates the 
control box 20 manually in a known way, such as by moving a switch or 
lever arm to a selected position. That is coupled by the control cable 24 
to the transmission 15 in a known way to select a desired one of a 
plurality of continuous ranges of the transmission 15 according to the 
user's operation of the control box 20, and then the transmission 15 
operates conventionally within the selected range to automatically vary 
the speed at which the pump is driven according to the load the liquid 
imposes. That is to say, the transmission operates at a reduced pump speed 
under heavier load conditions and vice versa, much the way an automatic 
transmission in an automobile operates under varying load conditions or 
drive requirements to vary the drive ratio between engine and wheels (as 
the automobile goes up and down hills, for example). 
In addition to the foregoing, the system 10 includes input means for 
connecting the pump 13 to an input line in fluid communication with a 
source of liquid, such as a three-inch line 25 in fluid communication with 
the vat 11, and output means for connecting the pump 13 to an output line 
in fluid communication with a destination, such as a three-inch line 26 in 
fluid communication with the semitrailer tank 12 (FIG. 1). In the system 
10, these functions are accomplished with an input manifold 27 connected 
by a conduit or line 28 in fluid communication with the inlet 17 of the 
pump 13, and an output manifold 29 connected by a conduit or line 30 with 
the outlet 18 of the pump 13. 
The input manifold 27 has four differently sized inlets 31-34, each one 
being suitably sized for connection to a different size conduit or line. 
In other words, the inlet 31 is sized to receive a 3-inch line, the inlet 
32 is sized to receive a 2-inch line, the inlet 33 is sized to receive a 1 
1/2 inch line, and the inlet 34 is sized to receive a 1-inch line. The 
output manifold is similarly configured, the outlets 35-38 receiving 
respective ones of 3-inch, 2-inch, 1 1/2 inch, and 1-inch lines. Thus, the 
system 10 can accommodate different size lines both from the standpoint of 
having a suitably sized inlet and from the standpoint of being able to 
accommodate the different load resulting or the simultaneous use of one 
line for packaging and another line for transfer. Of course, a different 
number and size of manifold inlets and outlets can be provided. 
Considering now FIG. 2, there is shown a portable pumping system or system 
100 constructed according to another aspect of the invention. It is 
similar in many respects to the system 10 so that many of its components 
are not described in further detail. For convenience, many of the 
reference numerals designating parts in the system 100 are increased by 
one hundred over those designating similar parts of the system 10. 
Similar to the system 10, the system 100 includes a pump 113 with which to 
pump a liquid, an input manifold 127 having a plurality of differently 
sized inlets (only inlet 131 being visible in FIG. 2) connected in fluid 
communication with the pump 113, and an output manifold 129 having a 
plurality of differently sized outlets 135-138 connected in fluid 
communication with the pump 113. It also includes an electric motor 114 
and an automatic transmission 115 connected between the pump 113 and the 
motor 114 for coupling the pump 113 to the motor 114 so that the speed at 
which the pump 113 is driven varies automatically according to the load 
the liquid imposes. A control box arrangement 120 is also provided that 
serves as means for controlling operation of the motor 114 and the 
automatic transmission 115. 
But unlike the system 10, the system 100 is configured for portable use. 
Thus, it includes a portable support structure 140 on which the other 
components are mounted by suitable known means. Although any of various 
portable support structures may be used, the support structure 140 takes 
the form of a cart with wheels 141 and a handle 142. It is arranged in 
this manner so that the system 100 can be transported manually (wheeled) 
to a selected pumping location. 
Operationally, a user moves the support structure 140 to the selected 
pumping location. Next, the user connects an input line to an 
appropriately sized one of the inlets, such as the inlet 131 (FIG. 2), and 
an output line an appropriately sized one of the outlets 135-138. The 
inlets and outlets can be provided with caps (not shown) that seal the 
unused inlets and outlets, and the cap is simply unscrewed from the ones 
to be used. 
Next, the user operates the motor 114 and the transmission 115 with the 
control box arrangement 120. This causes the pump 113 to pump the liquid. 
If the load increases, the transmission 115 automatically decreases the 
speed of the pump 113 so that the motor 114 can continue to operate at a 
substantially fixed speed, and vice versa if the load decreases. This 
occurs even if the pump 113 stops. If it is desired to reverse the flow of 
liquid, the REVERSE range of the transmission 115 is used. 
Thus, this invention provides a method of accommodating varying loads and 
pressures when pumping a liquid with a motor-driven pump. This is done by 
interposing an automatic transmission between the pump and a motor driving 
the pump in order to couple the pump to the motor so that the speed at 
which the pump is driven varies automatically according to the load. Doing 
this enables fully automatic adjustment to the load. It relieves worst 
case motor size requirements. It maintains processing speed. It simplifies 
start-stop operations. It avoids current surges, and it allows the motor 
to continue running at full speed after the pump has slowed significantly 
or even stopped. In addition, the torque converter absorbs surges causes 
by start-stop operation. 
Although an exemplary embodiment of the invention has been shown and 
described, many changes, modifications, and substitutions may be made by 
one having ordinary skill in the art without necessarily departing from 
the spirit and scope of the invention. For example, it is within the 
broader inventive concepts disclosed to use an automatic transmission for 
coupling a drive motor to other types of loads where obstructions or other 
conditions may cause the load to vary, such as a grain conveyor or luggage 
conveyor, for example, and the illustrations of the pumps in FIGS. 1 and 2 
are intended to cover such other loads.