BRPI1002730A2 - pump controller - Google Patents

Abstract

PUMP CONTROLLER. The present invention provides a technique using current detection to control pressure at a constant level without direct pressure detection. This technique will help to reduce only the dependence on the switch or sensor and its non-linearity and other associated problems, such as non-repetitive behavior, being affected by EMI etc. The technique includes using a pump controller featuring one or more modules configured to respond to one or more input signals containing information about the current supplied from a pump; and configured to provide one or more output signals containing information to control the pump to operate at a substantially constant pressure without direct detection of pump pressure. One or more modules control the operation of the pump based at least partially on a table of characteristics related to the voltage and current that is calibrated for each pump.

Description

PUMP CONTROLLER

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a technique for controlling the operation of a pump, including providing a method of controlling the operation of a pump at constant pressure using motor current as a detection parameter and motor voltage as a control parameter. .

More particularly, the present invention relates to a method and apparatus using a pump control to maintain a constant output pressure based on at least partially detecting motor current and a unique algorithm for following the V-I characteristics of a pump.

2. Brief Description of Related Art

Many pumps known in the art include a mechanical pressure switch, or semiconductor Hall sensors, or load cells, or any other type of electronic pressure sensing device, which shuts off the pump when a certain pressure (ie the pressure of shutdown) is exceeded. The pressure switch, Hall sensor or load cell is typically positioned in physical communication with the fluid in the pump. When the fluid pressure exceeds the shutoff pressure, the fluid force moves the mechanical switch to open the pump power circuit or generates a corresponding electrical signal to follow the set pressure. Mechanical switches have several limitations. For example, during repeated opening and closing of the pump power circuit, arcing and flaring often occurs between the switch contacts. Pressure cannot remain constant because of non-repetitive and / or nonlinear behavior. Thus relying completely on the switch or pressure sensor will always give an inconsistent control circuit.

In view of this, there is a need in the art for an improved pump controller that solves problems related to mechanical pressure switches or sensors in known pump designs.

SUMMARY OF THE INVENTION

To overcome the above mentioned problems with the mechanical pressure switch and pressure sensor, a new technique is provided using current sensing to control pressure at a constant level without direct pressure sensing. This new technique will help to reduce dependence solely on the switch or pressure sensor and its nonlinearity and other associated problems such as non-repetitive behavior as well. other known issues associated with being affected by electromagnetic interference (EMI), etc.

According to some embodiments, the present invention may take the form of apparatus, such as a pump controller, featuring one or more modules configured to respond to one or more input signals containing information about the supplied current of a pump; and also configured to provide one or more output signals containing the pump control information to operate at substantially constant pressure without direct pump pressure detection.

Embodiments of the present invention may also include one or more of the following characteristics: For example, one or more modules may be configured to control pump operation based on at least partially a table of voltage and current related characteristics that is calibrated for each pump, where characteristics can be determined with the following equation:

I = Vm + C, where m = (II - 12) / (V1 - V2), C = (V1 * I2 - V2 * I1) / (VI - V2), (VI, II): Low curve point, and (V2, 12): High curve point.

One or more input signals may contain information about a real motor current detected to operate the pump, and one or more output signals may contain information about a read voltage from the table that corresponds to the actual motor current detected. One or more input signals may also contain information about a real motor current comparison detected with an established current. One or more modules may also be configured to provide a correction term for controlling the pump to operate at substantially constant pressure.

One or more modules or the device as a whole can be configured as a PID controller to control pump operation.

The apparatus may also take the form of a controller featuring one or more signal processing modules configured to respond to one or more input signals containing information about the supplied current of a pump; and configured to provide one or more output signals containing information to control the pump to operate at substantially constant pressure without direct pump pressure detection. Controller embodiments may include one or more of the features described herein. The controller may also be part of a pumping system or arrangement including the pump.

The present invention may also take the form of a method featuring steps for controlling the pump, including responding to one or more input signals containing information about the supplied current of a pump; and providing one or more output signals containing information to control the pump to operate at substantially constant pressure without direct pump pressure detection. Embodiments of the method may include steps for implementing one or more of the features described herein.

The present invention may also take the form of a computer program product having a computer readable medium with a computer executable code inserted therein to implement the method steps when made in a signal processing device that is part of such a program. pump controller as element 10. As an example, the computer program product may take the form of a CD, a floppy disk, a memory card, as well as other types of memory devices that may store a computer executable code on such computer readable medium now known or developed later in the future.

BRIEF DESCRIPTION OF THE DRAWING

The drawing includes the following Figures, not drawn to scale:

Figure 1 includes Figures 1a and 1b, where Figure 1a is a block diagram of the apparatus including a pump controller according to some embodiments of the present invention; and wherein Figure Ib is a flowchart block diagram of a method for implementing the apparatus of Figure 1a according to some embodiments of the present invention.

Figure 2 is a graph of charge-flow characteristics for a diaphragm pump.

Figure 3 is a graph of current versus voltage showing V-I characteristics at a constant pressure of, for example, 206.8 kPa (30 PSI) for a diaphragm pump.

Figure 4 is a block diagram of apparatus including a pump system having a controller in accordance with some embodiments of the present invention.

Figure 5 shows a graph of current versus voltage having V-I characteristics for the desired current and current achieved at constant pressure for a diaphragm pump in accordance with some embodiments of the present invention.

Figure 6, which includes Figures 6a to 6h, shows a functional flow chart showing steps for implementing the apparatus in accordance with some embodiments of the present invention.

Figure 7 shows a graph having an operating flow / envelope curve that is part of PSI (= 6.89 KPa) to gallon per minute (= 3.78 liter per minute) according to some embodiments of the present invention. . Figure 8 shows the flow chart showing light emitting diode (LED) codes according to some embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1a shows the apparatus in the form of a pump controller generally indicated as 10 featuring one or more modules 12 and 14. One or more modules 12 are configured to respond to one or more input signals containing the supplied current information from each other. a pump (see element 30 (Figure 4); and also configured to provide one or more output signals containing information to control pump 30 (Figure 4) to operate at substantially constant pressure without direct pump pressure detection) .

According to some embodiments of the present invention, one or more modules 12 may be configured to control operation of pump 30 (Figure 4) based on at least partially a table of voltage and current related characteristics that is calibrated for each pump, where the characteristics can be determined with the following equation:

I = Vm + C,

where m = (I1 - 12) / (V1 - V2),

C = (V1 * 12 - V2 * I1) / (V1 - V2),

(V1, I1): Low curve point, and

(V2, I2): High curve point.

One or more input signals may contain information about a real motor current detected to operate the pump, and one or more output signals may contain information about a read voltage from a calibration table that corresponds to the actual motor current detected. One or more input signals may also contain information about a real motor current comparison detected with an established current. One or more modules 12 may also be configured to provide a correction term for controlling the pump to operate at substantially constant pressure.

One or more modules 12 or apparatus 10 as a whole may be configured as, or are part of, a module (see element 40 (Figure 4)) having a PID controller 41 along with other components or modules 42, 44, 46 48 described below for controlling the operation of pump 30. As shown, module 40 includes, for example, one or more signal processing modules configured to perform signal processing to implement the functionality of the present invention. PID controller 40 may also be part of a pumping system or arrangement generally indicated as 50 in Figure 4 to control pump operation 30.

One or more modules 14 may include other modules that may be part of the pump controller to implement other controller functionality that is not part of the underlying invention, for example, including input / output functionality for processing signaling to and from a pump. / engine, a detection device, etc., as well as functionality associated with other devices or components, for example, including a random access memory (RAM) type device, a read-only memory (ROM) type device, data bus and control, etc. The calibration table may be part of, for example, a memory storage device. The memory storage device itself may be part of one or more modules 12, one or more other modules 14, or some combination thereof. Memory storage devices are known in the art, and the scope of the invention is not intended to be limited to any particular type thereof now known or developed later in the future.

The present invention may also take the form of a method shown in Figure Ib having steps 22, 24 which are part of a flow chart generally indicated as 20 for controlling the pump 30 (Figure 4), including responding to one or more signal signals. input containing information about the supplied current of pump 30, for example, along signal path 42a (Figure 4); and providing one or more output signals, for example along signal path 41a (Figure 4), containing information for controlling pump 30 to operate at substantially constant pressure without direct detection of pump pressure.

Basic Pump Principle and Table Construction The above indirect relationship between current and pressure in accordance with the present invention is based at least in part on the principle of operation and accumulation of general diaphragm pumps consistent with the following:

As one skilled in the art would appreciate, a typical diaphragm pump voltage is applied to a motor which in turn will rotate a rotor. The rotational motion will be transferred to a piston by a cam. The piston in turn will convert rotational motion to linear motion. Linear movement of the piston to a diaphragm will force fluid from the pump inlet to its outlet. This force in the outlet area will generate the pressure in the fluid flowing from the outlet.

In operation, if the demand at the pump outlet is decreased, then the outlet pressure will increase. However, the pump is still spinning at the same speed as before.

Because of this, the current will begin to increase in the motor in response to increased pressure. In the same way, if the pressure at the pump outlet is decreased to the desired pressure, then the flowing motor current will decrease while the torque demand to generate more pressure decreases.

As an example, Figure 2 is provided to show the general load-flow characteristics for a typical diaphragm pump. From the characteristics, current and voltage are understood to be substantially unique to the desired charge-flow. Another important result is that the pressure at the two different flow rates is understood to substantially not have the same voltage and current at any given time.

To support understanding of the above principle, Figure 3 is provided to show a characteristic V-I at constant pressure for a typical diaphragm pump, which forms the basis for the table or table lookup technique according to the present invention.

VI characteristics can be determined by varying the voltages applied to the pump for its entire operating range (eg 8.5 V to 14.8 V for + 12 V motor and without any control electronics, ie a variable speed drive). (VSD)) and mark the current by maintaining the constant pressure which is the desired constant pressure at which the pump needs to be maintained when it is in its intended normal operation (eg 30 pounds per square inch PSI (206.8 kPa)).

It is understood that the respective VI characteristics in Figure 3 which determine the table for a given pump are unique to that given pump since the VI characteristics substantially depend on the motor characteristics of that given pump, which typically vary from one engine compared to another. motor. That is, according to the present invention the respective V-I characteristics will be detected and determined for each pump and a respective table will be formulated for each pump that are unique to each pump, and used to control each pump.

Once the VI characteristics for the given pump are determined, any controller or control system can be implemented to control the pump at constant pressure by observing and following the obtained trend line (VI characteristics) using the table repetition technique accordingly. with the present invention.

As an example, Figure 4 shows a diagram of a control block for a pump system 50 having effective yet simple approaches according to some embodiments of the present invention. As shown, the control block or module 40 includes devices, components, or modules, such as controller module PI (D) 41, along with other components or modules 42, 44, 46, 48 for controlling pump operation 30. Module 42 detects motor current along signal path 42a, and provides a current sensing signal along signal path 42b containing information on detected motor current. Module 44 is configured to respond to the current sensing signal along signal path 42b, to measure current at a motor voltage, and provides a measured current signal along signal path 44a containing current information. measured at this motor voltage. One or more input signals containing supplied current information from pump 30 (Figure 4) includes the current sensing signal along signal path 42b. Module 46 is configured to respond to a voltage output signal E along signal path 41a provided from PI Controller Module (D) 41 to pump 30 along signal path 41a to control operation of pump 30, current set at a particular voltage (calibration), and provide a signal along signal path 46a containing information about the current set at the particular voltage (calibration). Node module 48 is configured to respond to signal along signal path 44a containing information on current measured at motor voltage and signal along signal path 46a containing information on current set at particular voltage (calibration). ), and provides a signal e along signal path 48a to module PI (D) 41 containing information about the two signals. Consistent with that described in further detail below, signal e supplied from node module 48 to module PI (D) 41 along signal path 48a contains information about an error between the set current and actual detected motor current that will be used. as an input parameter for the PID controller 41. The PI (D) module 41 is configured to respond to one or more input signals, including the signal and along signal path 48a containing information about the supplied current of pump 30. as well as voltage output signal E along signal path 41a provided from PI Controller Module (D) 41 to pump 30 along signal path 41a to control operation of pump 30, voltage signal E along signal path 41a to pump 30 along signal path 41a to control pump operation 30. Consistent with that described in further detail below, voltage signal E of module PI (D) 41 to pump 30 along the dress Signal 41a will contain the correction term for motor voltage to achieve the desired pressure. One or more output signals containing information for controlling pump 30 (Figure 4) to operate at substantially constant pressure without direct pump pressure detection include voltage output signal E along signal path 41a. In operation, voltage output signal E along signal path 41a to control operation of pump 30 is effectively corrected or modified based at least partially on the control response system shown in Figure 4 which depends on a relationship between motor current detected and the information contained in the calibrated table for the respective pump 30 to operate the respective pump 30 at substantially constant pressure without direct pump pressure detection.

The scope of the invention is not intended to be limited to the type of signal path being used to exchange the signal between the components or modules shown and described herein. Modalities are provided by using signal paths that are wired between the components or modules shown and described herein, or wireless communication couplings between the components or modules shown and described herein, or some combination thereof, as well as other types of signal paths now known or developed later in the future.

Figure 5 shows a voltage plot of current having characteristics VI for the desired current indicated as D (shown as having a lighter colored function) and the achieved current indicated as A (shown as having a darker colored function) at a constant pressure without direct pump pressure detection to control the operation of a diaphragm pump according to some embodiments of the present invention. In operation, one or more modules 12 (Figure 1) or 41 (Figure 4) are configured to provide a correction term, for example, in the form of a modified voltage signal along signal path 41a, to control the pump. to operate at substantially constant pressure such that the desired current and the achieved current A have similar values at a similar motor voltage as shown in the graph of Figure 5 for controlling the operation of a diaphragm pump without direct pump pressure detection, according to some embodiments of the present invention.

This control implementation according to the present invention as described herein provides a highly accurate, yet easy to fix control algorithm implementation, which provides a mountable linear approach that is easy to calibrate (get VI characteristics) and has less computational load. on the controller.

Reproduction of the V-I curve is done using the linear mountable method. According to the mountable linear method, the curve is divided into (ideally infinite) number of small linear lines. Here you get two points (calibration point) and the relationship between those two consecutive points will have the linear relationship. This relationship can be defined with the following equation.

I = Vm + C m = (II - 12) / (V1-V2) C = (V1 * I2 - V2 * I1) / (V1-V2) (VI, II): Low curve point; (V2,12): High curve point;

Under normal conditions, the pump will detect actual motor current and apply voltage to the motor. The same voltage will be sent to the set current prediction logic to achieve the set current for the desired pressure at the present motor voltage. The actual motor current detected will be compared to the set current (desired current at that voltage for desired pressure - from the calibration table). The error between the set current and the actual detected motor current will be used as the input parameter for the PID controller. The PID controller will generate the correction term for the motor voltage (controller per duty cycle) to achieve the desired pressure. Next time the above steps are repeated at a very fast and constant rate.

Since the algorithm is implemented consistent with that determined herein, through electronic and signal processing, one or more output signals along signal path 41a may be provided to achieve the output giving the desired constant pressure at the output of the signal. pump through the predictive algorithm approach according to the present invention.

V-I CURVE EQUATION

The following is a description with respect to the curve equation V-I:

From a general linear equation:

I = mV + C,

where: (V1, I1): Low curve point, and

(V2, I2): High curve point has:

<formula> formula see original document page 16 </formula> <formula> formula see original document page 17 </formula>

Based at least partially on this, Curve V-I is:

<formula> formula see original document page 17 </formula>

Modules 12, 41, 42, 44, 46 or 48

As an example, the functionality of modules 12, 41, 42, 44, 46 or 48 may be implemented using hardware, software, firmware, or a combination thereof. In a typical software implementation, modules 12, 41, 42, 44, 46, or 48 would include one or more microprocessor-based architectures having a microprocessor, random access memory (RAM), read-only memory (ROM). , input / output and control devices, data and address bus connecting them. One skilled in the art would be able to program such a microcontroller (or microprocessor) based implementation to accomplish the functionality described herein without improper experimentation. The scope of the invention is not intended to be limited to any particular implementation using technology now known or developed later in the future.

POSSIBLE APPLICATIONS

Possible applications for the present invention include an implementation having some combination of the following characteristics:

I. General Description:

As an example, the specification below is for the design and development of a variable speed drive pump (VSD) controller for a five chamber pump. As an example, applications for this specification may vary from a general industrial spray water system, although the scope of the invention is not intended to be limited to the type of application now known or developed later in the future.

II. Functional Requirements

1. Application Classification

1.1. I work in salt and fresh water environments.

1.2. Voltage

1.2.1. Direct Current Unit - 9.5 VDC - 28.0 VDC

1.2.2. AC unit - 85 VAC - 250

VAC - Phase two of the project to be completed upon completion of the DC version.

2. Abbreviations and Definitions

2.1. Abbreviations

2.1.1. #F - Number of outlets / valves / taps

2.1.2. C # - Flow curve at various voltages

2.1.3. P # - Rating point at various pressures and flow

2.1.4. GPM - Gallons per minute

2.1.5. VDC - Direct Voltage Current

2.1.6. VAC - Alternating Voltage Current

2.1.7. MTBF - Mean Time Between Failure

2.1.8. PSI - Pound per square inch 2.2. Definitions

2.2.1. Output - Any system flow output

2.2.2. Dry Run - Occurs when liquid supplied to the pump is removed or the source is depleted.

2.2.3. Prime Time - The amount of time it takes for the pump to draw water and start pumping.

3. Performance / Life Expectancy

3.1. Performance

3.1.1. Functional Operations (see Figures 6-8)

3.1.1.1. With a VSD pump installed in an RV / container and the appropriate power source connected, the pump controller, for example controller 10 (Figure 1) or module 40 (Figure 4), can also perform a diagnostic test as determined and described. in Figure 6 each time the pump experiments an on / off cycle. Under normal operating mode, the water system must be pressurized and maintained at projected value until demand is required (open outlet).

3.1.1.2. When there is a demand (PI), (P2), or (P3), the pump controller starts the pump at full speed / voltage, the pump will presumably run outside the operating envelope (high ampere / volt), the pump controller can detect this condition and delay the pump until a preset ampere / volt value is achieved. You can keep pump operation at this value until the new condition arises and the pump controller can react to the new condition. All of these actions typically happen in a very short time, for example, a fraction of a second.

3.1.1.3. As more demand on (P2) or (P3) or (P4) arises, the water system drops under pressure and the pump experiences a drop in load / ampere extraction. The pump controller can detect this new condition and slowly accelerate the pump until a preset value (ampere / volt) is achieved, and can maintain pump operation at this value until a new condition arises and the controller would react to the new one. condition. This technique can be applied to all operating points defined as the operating envelope described in Figure 7.

3.1.1.4. If a high demand (P4) is required, the pump controller can maintain full speed / voltage to keep up with demand until this condition is changed.

3.1.1.5. When a demand is no longer present (output closed), the pump experiences a high pressure above operating pressure, a pressure switch can disconnect power to the pump.

3.1.1.6. Dry Run Protection - If there is no fluid in the tank / pump inlet, the pump controller can detect this condition and shut off the pump after some predetermined time, for example X minutes. The controller may also turn on the pump from time to time to test empty / leak condition for a predetermined number of times and send the error signal to the LED.

3.1.1.7. Learning - During all modes of operation, the pump controller can "Learn" the voltage / ampere operating range for future reference. Learning can allow the unit to move smoothly with less time wasted.

3.1.1.8. Over Current / Undercurrent - The controller can monitor extremes at amperage outside the learned range, and will turn off and flash LED 1 flashes when this condition occurs. See Figures 6 and 8.

3.1.1.9. Leak Detection - The unit can monitor slow leaks for a while, when the pump controller detects slow leaks for a time without normal operation, the unit can shut down the pump. A slow leak typically manifests as a slow pressure loss, so the pump raises the pressure and shuts off. This can occur constantly over time in a leak situation. This feature may allow some predetermined cycle period then shuts off and flashes the 2 LED flashes. See Figures 6 and 8.

3.1.1.10. Data storage

The pump controller may also be configured to store data in onboard memory, for example, which may be part of one or more other modules 14, including the following incidents:

The. Dry Run / Undercurrent - Records the number of dry run incidents.

B. Over current / engine stop - Logs the number of incidents

ç. Hours for normal operation

d. Hours at time of each incident

and. Undervoltage / Overvoltage - Logs the number of incidents

f. Leak Detection - Logs the number of incidents

g. Timeout - Logs the number of incidents

3.2. Life Expectancy - Recommended Functional Life (MTBF); 500 box hours to include water operation and ingress.

4. Physical characteristics and dimensions 4.1. VSD housing will be set to mount as a motor base.

4.2. Power connections may be 12 inch (30.48 cm) connections of sufficient caliber to support 28 amps and allow sufficient wiring of the mooring to be reliably connected.

4.3. Connections

4.3.1. Pump connections may be based on the 8-pin Molex MX15 0 connector or equivalent to be molded into

4.3.1.2: 2 pins to connect + 1 grounding pin connection

4.3.1.3:2 pins for power to the motor

4.3.1.4: 2 pins for pressure switch input

4.3.1.5: 2-pin LED indicator and ON / OFF switch option.

These pins plugged in unless required.

5. Some Additional Features

5.1. Thermal overload protection

5.2. The unit must also, in addition to software overcurrent protection, use hardware redundancy for overcurrent protection.

5.3. You will have hardware overcurrent protection if the software overcurrent fails.

5.4. Will conform to PCB result (s) provided by ITT Flow Control

5.5. SMT / THT Construction 5.6. Operating temperature range -23 ° C to 65.5 ° C

5.7. Amp / Voltage Surge Protection

The advantages of the above implementations are numerous, and as an example, may include some of the following.

· Universal equation

• Extends and fits any diaphragm pump characteristics and ratings (same software for 30 PSI (206.8 kPa), 60 PSI (413.7 kPa), 80 PSI (551.6 kPa, etc.) pump.

· Software fits particular engine characteristics

• Functionality primarily depends on calibration

• Easy calibration

• Easy portability for AC operations too

· Higher number of self-diagnostic features may be given (as most errors may be a current function)

• Uses advanced ecumenical algorithm

• Algorithm uses assertion logic

· Common software can be adjusted for any diaphragm pump characteristics and ratings (same software for 1 PSI (6.89 kPa) to 250 PSI (1.72 MPa)) once current handling capabilities are met by the hardware

· Software could be self-calibrated or externally calibrated

• The software uses no pressure "sensors" for its main computational algorithm and does all calculations based on motor current; thus "without sensor".

· The software establishes a relationship between motor current and output pressure with its highly advanced algorithm your output pressure control requirements.

• Smooth and calm flow at the outlet.

• Discharge pressure remains constant for extended range flow requirements (approximately 85% of full flow range).

• Minimum output flow variation with change in input voltages

• Fast response software algorithm with sophisticated and advanced onboard electronic control.

• Extended pump life while advanced software assimilates and absorbs all higher voltages than rated voltages going to the motor.

• Subjugated heat generation in the motor as a result of no higher than rated voltage applied to the pump.

• An array of indicative self-diagnostic features provided with the help of superior hardware and software combination; diagnostic features such as dry running, locking rotor, leak detection, timeout, over voltage, under voltage, over current, etc.

• Pump dry running, system leak detection, timeout, over voltage, undervoltage.

These are categorized as system issues.

• Over current, no current (undercurrent), overheating of an enclosed space are categorized as pump problems.

• These diagnostics are the visual indication by flashing the LED on the output. • LED exit codes are widely accumulated as "System" or "Pump" problems / errors.

• LED output can also be given for each diagnostic feature individually by changing the error code module in the software.

• Onboard super temperature limit improves the life of electronics and ensures the product.

• Conserve water with advanced leak detection feature.

Scope of the Invention

It should be understood that unless otherwise indicated herein, any of the features, alternatives or modifications described with respect to a particular embodiment herein may also be applied, used, or incorporated with any other embodiment described herein. Also, the drawings here are not drawn to scale.

Although the present invention is described by way of example with respect to a diaphragm pump, the scope of the invention is intended to include use thereof with respect to other types of pumps now known or developed later in the future.

While the invention has been described and illustrated with respect to exemplary embodiments thereof, the foregoing and various other additions may be made therein and without departing from the inventive concept and scope of the present invention.

Claims (20)

Apparatus including a pump controller, comprising: one or more modules configured to respond to one or more input signals containing information about the supplied current of a pump; and configured to provide one or more output signals containing information for controlling the pump to operate at substantially constant pressure without direct pump pressure detection. Apparatus according to claim 1, characterized in that one or more modules are configured to control pump operation based at least partially on a table of voltage and current related characteristics that is calibrated for each pump. Apparatus according to claim 2, characterized in that the voltage and current related characteristics are determined with the following equation: I = Vm + C, where m = (II - I2) / (V1-V2) , C = (VI * 12 - V2 * II) / (VI - V2), (VI, II): Low curve point, and (V2, 12): High curve point Apparatus according to claim 2, characterized in that one or more input signals contain information about a real motor current detected to operate the pump, and one or more output signals contain information about a read voltage of the pump. table that corresponds to the actual motor current detected. Apparatus according to claim 4, characterized in that one or more input signals contain information about a comparison of the actual motor current detected with an established current. Apparatus according to claim 5, characterized in that one or more modules are configured to provide a correction term for controlling the pump to operate at substantially constant pressure. Apparatus according to claim 1, characterized in that one or more modules are configured as a PID controller to control pump operation. A pump system comprising: a controller having one or more signal processing modules configured to respond to one or more input signals containing information about the supplied current of a pump; and configured to provide one or more output signals containing information to control the pump to operate at substantially constant pressure without direct pump pressure detection. Pump system according to claim 8, characterized in that one or more signal processing modules are configured to control pump operation based at least partially on a table of voltage and current related characteristics which are calibrated for each pump. Pump system according to Claim 9, characterized in that the voltage and current characteristics are determined by the following equation: I = Vm + C, where m = (II - 12) / (V1- V2), C = (V1 * I2 - V2 * I1) / (V1 - V2), (VI, II): Low curve point, and (V2, 12): High curve point. Pump system according to claim 9, characterized in that one or more input signals contain information about a real motor current detected to operate the pump, and one or more output signals contain information about a voltage. read from the table that corresponds to the actual motor current detected. Pump system according to claim -11, characterized in that one or more input signals contain information about a comparison of the actual motor current detected with an established current. Pump system according to claim -12, characterized in that one or more signal processing modules are configured to provide a correction term for controlling the pump to operate at substantially constant pressure. Pump system according to claim 8, characterized in that the controller is configured as a PID controller to control pump operation. Pump system according to claim 8, characterized in that the controller is part of a pumping system or arrangement having a pump. A method comprising: responding to one or more input signals containing information about the supplied current of a pump; and providing one or more output signals containing information for controlling the pump to operate at substantially constant pressure without direct pump pressure detection. Method according to claim 16, characterized in that the method comprises controlling with one or more pump operating modules based at least partially on a table of voltage and current related characteristics which is calibrated for each pump. Method according to claim 17, characterized in that the method comprises determining voltage and current related characteristics with the following equation: I = Vm + C, where m = (I1 - I2) / (V1- V2), C = (V1 * I2 - V2 * I1) / (VI - V2), (V1, I1): Low curve point, and (V2, I2): High curve point. Method according to claim 17, characterized in that one or more input signals contain information about a real motor current detected to operate the pump, and one or more output signals contain information about a read voltage of the pump. table corresponding to the actual motor current detected, particularly where one or more input signals contain information on a comparison of the actual motor current detected with an established current. Method according to claim 19, characterized in that the method comprises providing one or more modules with a correction term for controlling the pump to operate at substantially constant pressure.