Pump apparatus with integrated safe torque disconnect function

Abstract

A pump device comprises a rotary pump mechanism (P) arranged to pump fluid between a fluid inlet and a fluid outlet, and an electric motor (MT) arranged to rotate a connected shaft to rotate the rotary pump mechanism (P). A motor driver (MD) is connected to the electric motor (MT) for driving the electric motor (MT) according to a variable frequency drive scheme. A safety circuit (STO) is connected to the motor drive (MD) and has first and second electrical inputs (I1, I2) for connecting external electrical switches (SW1, SW2). The safety circuit (STO) can enter a safe torque off state to stop torque generation of the motor MT, the safety circuit (STO) being designed with redundancy to enter the safe torque off state in the event of a fault, preferably in accordance with EN ISO 13849-1: 2015 Class 3. The housing (H) forms a housing in which the motor driver (MD) and the safety circuit (STO) are located. The housing (H) is attached to an electric motor (MT), for example, to an electrically conductive motor housing of the electric motor (MT). The housing (H) may partially or entirely enclose the electric motor (MT) and the pump mechanism (P). The pump device provides a compact pump device with integrated safety functions, allows easy installation in applications with safety requirements, and allows rapid restart after safety mode.

Description

Technical Field

[0001] The present invention relates to the field of pump equipment, and more particularly, to the field of pumps driven by an electric motor. In particular, the present invention relates to a pump equipment with an integrated safety function. More specifically, the present invention provides a pump equipment with an integrated safety torque off function. Background Art

[0002] Pump equipment driven by an electric motor is widely used and comes in various sizes. For many applications, if a person approaches the pump or other equipment driven by the pump, the pump operates in an environment where the safety of the person is threatened. Here, safety requirements stipulate, for example, that a set of electrical switches must be used to detect whether a door is opened during pump operation, and in such a case, the pump should stop operating.

[0003] This safety stop can be achieved by cutting off the power supply to the electric motor driving the pump, for example, the electric power of the electric motor ranges from 1 - 50 kW. However, this usually results in a time-consuming restart of the pump after the safety stop, for example, to restart the motor controller. This may be unacceptable for applications of pump equipment where many such safety stops can be expected.

[0004] There are other implementations of safety functions. For example, they meet the requirements of Safety Integrity Level (SIL) 3 of IEC 61508 - 1:2010 and follow the guidelines of Performance Level e, Category 3 of EN ISO 13849 - 1:2015 regarding safety torque off circuits with sub-functions. However, such solutions are bulky because they require a larger amount of space and components such as at least two optocouplers for electrical isolation. Therefore, such solutions are implemented as separate components for specific applications connected to the pump equipment. Summary of the Invention

[0005] The object of the present invention is to provide a general pump equipment that can be used for a variety of applications, including those that require a safety mode function.

[0006] The first aspect of the present invention provides a pump equipment, comprising

[0007] A rotary pump mechanism arranged to pump fluid between a fluid inlet and a fluid outlet,

[0008] An electric motor arranged to rotate a shaft, wherein the shaft is connected to rotate the pump mechanism,

[0009] A motor driver connected to the electric motor and arranged to drive the electric motor according to a variable frequency drive scheme,

[0010] A safety circuit, which is connected to the electric motor and has first and second electrical inputs arranged to be connected to respective first and second external electrical switches or contacts. The safety circuit is arranged to enter a safe torque-off state to stop the electric motor from generating torque. The safety circuit is designed to have redundancy to enter the safe torque-off state in case of a fault, and

[0011] A housing that forms an outer casing, where the motor drive and the safety circuit are located within the outer casing, and the housing is attached to the electric motor.

[0012] Such a pump device is advantageous because it can be used in various applications that require safety functions, which are safety functions to provide a safe mode with stop or torque-off functions of the pump device related to the opening of an AND gate or port, a grating bar, a light guard with proximity sensors, etc. The pump device with such an integrated safety function can be directly connected to safety switches or contacts that have already been implemented as part of an application without the need to consider any further pump- or motor-specific requirements in a particular application.

[0013] This helps to install the pump device into applications with safety requirements. There is no need to install an additional safety circuit between the safety switch / contacts and the pump device. The pump device can be implemented with electrical terminals for connection to safety switches / contacts on the outer surface of the housing to facilitate installation.

[0014] In a preferred embodiment, a safe torque-off circuit conforming to Category 3 of EN ISO 13849-1:2015 can be implemented using only one optocoupler, saving space compared to prior art solutions that require at least two optocouplers. Thus, the pump device is also suitable for compact models.

[0015] Furthermore, compared to safety functions that completely cut off the power supply of the pump device in the safe mode, the proposed solution with a safe torque-off circuit allows for a short start-up time of the pump device, which is important for many applications. This is achieved by the safe torque-off circuit that allows power supply to the electric motor during the safe mode, including motor control functions, thus eliminating the need for a complete motor control restart of the pump device at startup.

[0016] In the following, preferred features and embodiments will be described.

[0017] Preferably, the safety circuit is arranged to meet the requirements of the safe torque-off safety sub-function according to IEC 61800-5-2:2016, and preferably also meets the requirements of Category 3 of EN ISO 13849-1:2015. This provides a high level of safety with a fail-safe function.

[0018] Preferably, the safety circuit includes at least one electrical isolator component for electrically isolating the first and second electrical inputs from the motor driver. In particular, the at least one electrical isolator component can be implemented by a single optocoupler. It has been specifically found that a safe torque-off circuit compliant with Category 3 of EN ISO 13849-1:2015 can be implemented, where only a single optocoupler can be used, thus saving space compared to known solutions.

[0019] More specifically, the safety circuit can include a pulse generator and a modulator, where the output of the modulator is connected to the input of the single optocoupler. More specifically, the pulse generator is preferably connected to the second electrical input and is arranged to generate an oscillating electrical output voltage at the output when powered from the second electrical input. More specifically, the pulse generator can be arranged to generate an output voltage that switches between two levels. Even more specifically, the pulse generator can be arranged to oscillate at a frequency of 1 - 100 kHz (such as 10 - 20 kHz, such as 14 - 16 kHz) between two output voltage levels. In particular, the pulse generator can be arranged to generate an output voltage that switches between a DC voltage and electrical ground (0V). The DC voltage can be 1 - 50V, such as 10 - 40V, such as 20 - 30V. In a preferred embodiment, the pulse generator is arranged to oscillate between 24V and 0V. The modulator can be connected to the first electrical input and output of the pulse generator, where the modulator is arranged to generate an electrical output signal at a rate defined by the pulse generator, and the electrical output signal is a modulated version of the voltage at the first input.

[0020] In a preferred embodiment, the safety circuit includes first and second logic comparator blocks arranged to receive electrical output signals from an electrical isolator component and provide respective first and second logic outputs accordingly. In particular, each of the first and second logic comparator blocks includes a pulse detector connected to receive the electrical output signal from the electrical isolator component, wherein the first and second logic comparator blocks are arranged to generate respective first and second logic outputs based on the outputs of their respective pulse detectors. In particular, the first and second logic comparator blocks may be connected to gate respective high and low gate driver outputs for driving respective high and low gate driver portions of a motor driver based on the first and second logic outputs. Specifically, this is done so that both the high and low gate driver portions of the motor driver can be driven only if both the first and second pulse detection outputs indicate that both the first and second pulse detectors have detected a pulse signal. More specifically, respective first and second logic gates such as AND gates may be arranged to receive the respective first and second logic outputs and gate the respective high and low gate driver outputs accordingly to drive respective high and low gate driver portions of the motor driver. In some versions of single-phase motors, the high and low gate driver outputs can only achieve single-phase. In versions of three-phase motors, each high and low gate driver output includes three electrical phases.

[0021] In some embodiments, the safety circuit is implemented on a single circuit board and connected to the input of an electrical isolator component (such as an optocoupler) that is implemented on another circuit board together with components forming a motor driver. However, if desired, both the safety circuit and the components forming the motor driver can be implemented on a single circuit board.

[0022] The electric motor may be arranged to be connected to an AC power supply, for example, an AC power supply providing an AC power input of 100V AC to 500V AC, such as a common power grid. In some embodiments, for example, for solar power generation, a pump device may be configured to receive a power input in the form of a DC voltage (for example, in the form of a positive DC voltage and a negative DC voltage).

[0023] The electric motor can be any known motor technology including a stator and a rotor to rotate a shaft. The electric motor can be a permanent magnet motor, however, the electric motor is not limited thereto.

[0024] The rotary pump mechanism can be based on any known pump technology. For example, the rotary pump mechanism can include an impeller arranged to rotate within an impeller housing for pumping a fluid (for example, a liquid such as water) from a fluid inlet to a fluid outlet when rotating.

[0025] In some embodiments, the housing may extend around the rotary pump mechanism, for example, be partially or fully integrated with the conductive motor housing. The housing is preferably made of a composite material of another non-conductive material. However, other materials may be used. The housing may have an electrical isolation layer in its inner part.

[0026] The housing may enclose all the electronic components of the pump device. The housing preferably has an opening that allows electrical connection to a power source. For example, it may have pipe connections for fluid inlet and fluid outlet.

[0027] The housing preferably has an opening to allow external access to the first and second electrical inputs of the safety circuit.

[0028] It should be understood that the present invention is applicable to pump devices of various sizes. For example, pumps with electric motors having an electric power range of 1 W to 100 W, however, it can also be used for pump devices with electric motors having an electric power range of 100 W to 1 kW, or pumps with a power range of 1 - 50 kW or larger.

[0029] Those skilled in the art will know how to implement the present invention based on the disclosure of this specification and the general knowledge in the technical field.

[0030] In a second aspect, the present invention provides a system including

[0031] a pump device according to the first aspect, and

[0032] first and second switches or contacts connected to the first and second electrical inputs of the safety circuit.

[0033] Such a system can be used in many application scenarios that require safety functions. A pump device with such a built-in safety function is highly versatile because it can be directly connected to safety switches or contacts that have already been implemented as part of an application without any further pump-specific requirements.

[0034] In a specific example, the first and second electrical contacts can be used to detect the opening of a door or a port. In particular, the first and second electrical contacts can be part of an emergency stop. In particular, the first and second electrical contacts can be implemented as part of a grating barrier. In particular, the first and second electrical contacts can be implemented as part of a light protection device including proximity sensors.

[0035] More specifically, the system may include a control system to control the functions of one or more pump devices. Specifically, the system may be a utility, such as a water, heat, or cooling utility.

[0036] In a third aspect, the present invention provides a use of the pump device according to the first aspect. Specifically, the use can be for one of the following applications: a horizontally mounted multi-stage end suction pump, a horizontally mounted single-stage end suction pump, a vertically mounted multi-stage pump, a vertically mounted single-stage pump, a biobooster filter module, a washing or cleaning device, a stable ventilation, an industrial ventilation, a transportation system, a process system, a gear, a hydraulic device, a machine, and a machine tool.

[0037] The above aspects of the present invention can be combined. These aspects and other aspects of the present invention will become apparent and be elucidated with reference to the embodiments described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The pump device according to the present invention will now be described in more detail with reference to the drawings. The drawings illustrate one way of implementing the present invention and should not be construed as limiting other possible embodiments falling within the scope of the appended claims.

[0039] Figure 1 A schematic diagram showing the components of an embodiment of the pump device, and

[0040] Figure 2 A schematic diagram showing a preferred safety torque off circuit integrated in the housing of the pump device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] Figure 1 A block diagram showing an embodiment of the pump device, the pump device including a rotary pump mechanism P for pumping fluid between a fluid inlet and a fluid outlet. A motor MT is arranged as a rotating shaft, and the motor MT is mounted to rotate the rotary pump mechanism. The motor MT has a motor drive MD, and the motor drive MD is connected to drive the motor according to a variable frequency drive scheme.

[0042] In addition, the pump device further includes a safety circuit STO, preferably a safety torque off circuit. The safety circuit STO is connected to the motor drive MD and has first and second electrical inputs I1, I2. The first and second electrical inputs I1, I2 are arranged to be connected to respective first and second external electrical switches or contacts SW1, SW2. For example, they are connected to detect the opening of a door or a port or other safety detection functions. The purpose of the circuit STO is to provide a safety function for the motor MT. When one of the switches SW1, SW2 is detected to be closed, the motor MT stops generating torque, thereby causing the pump mechanism P to stop rotating. The safety circuit STO is arranged to enter a safety torque off state, causing the motor MT to stop generating torque. Among them, the safety circuit STO is designed to have redundancy to enter a safety torque off state in case of a failure. In the most preferred embodiment, the safety circuit STO meets the requirements of EN ISO 13849-1:2015 Category 3, which requires the fail-safe operation of the safety torque off circuit STO.

[0043] The Safe Torque Off circuit STO is connected to the motor drive MD of the electric motor MT. More specifically, the Safe Torque Off circuit STO is preferably arranged to gate the output GD_H, GD_L to the electrode drive MD for driving the respective high and low gate driver sections of the motor drive MD. Thus, if the Safe Torque Off circuit STO detects that any one of the safety switches SW1, SW2 is closed, the Safe Torque Off circuit STO can manipulate the high and low gate driver signals of the motor drive MD, thereby causing the motor to stop generating torque.

[0044] The housing H forms an outer shell in which the motor drive MD and the safety circuit STO are located. In particular, the safety circuit STO and the motor drive MD can be implemented partially or fully integrated, for example, sharing electronic components on the same circuit board.

[0045] The housing H is attached to the electric motor MT, preferably attached to the conductive casing of the electric motor MT so as to partially or completely surround the conductive casing of the motor. In addition, the housing H can partially or completely surround the pump mechanism P. Preferably, the housing H provides external access to the first and second electrical inputs I1, I2 of the safety circuit STO so as to facilitate connection to external safety electrical switches or contacts SW1, SW2. In this way, the pump device is very suitable for easy use in applications where safety functions are required.

[0046] In a preferred embodiment of the safety circuit STO, which will be explained hereinafter, the safety circuit STO can be implemented with a minimum number of bulky components, which makes the housing H compact. In addition, the safety circuit STO can be implemented to quickly restart the pump P after a safe mode stop, because with the Safe Torque Off circuit STO, power can be maintained for all components controlling the electric motor MT, including the motor drive MD and any control functions with software. Thus, restarting of the motor control is eliminated in the safe mode, which allows for a quick start-up time after a safe mode stop.

[0047] The pump device has the advantage that the safety function is provided as an integral part of the pump device. This makes it possible to easily install the pump device in applications where safety functions are required without the need for an external safety circuit, which usually requires completely cutting off the power supply of the pump device in the safe mode.

[0048] Figure 2Shows a preferred safety circuit, namely the Safe Torque Off circuit STO, which is illustrated in a functional block diagram for explaining the function of the circuit. The circuit has two electrical inputs I1, I2. These inputs I1, I2 are connected to two safety switches SW1, SW2. As shown, the two switches SW1, SW2 are interconnected at the midpoint, and the midpoint is connected to a fixed DC voltage DCV, such as 10 - 30V, for example a voltage source of 24V, and this voltage DCV can generally be used as the power supply for the electrical components of the Safe Torque Off circuit STO.

[0049] The pulse generator PG is connected to the second electrical input I2 and is arranged to generate an oscillating electrical output voltage when powered from the second electrical input I2, and this oscillating electrical output voltage oscillates between electrical ground (0V) and 24V at 15 kHz.

[0050] The modulator MOD is connected to the first electrical input I1 and the output of the pulse generator PG. The modulator MOD generates an electrical output signal at a rate defined by the pulse generator PG controlled by the second input I2, and this electrical output signal is a modulated version of the voltage at the first input I1.

[0051] The electrical isolator component (such as the optocoupler OPT) is connected to receive the electrical output signal from the modulator MOD and is accordingly arranged to generate an electrical output signal that is electrically isolated from the electrical output signal of the modulator MOD.

[0052] The first and second logic comparator blocks B1, B2 are both arranged to receive the output from the optocoupler OPT and accordingly provide their respective first and second logic outputs O1, O2.

[0053] Each of the two logic comparator blocks B1, B2 includes pulse detectors PD1, PD2. The pulse detectors PD1, PD2 are connected to receive the output from the optocoupler OPT and are arranged to generate their respective logic outputs O1, O2 according to the output of their respective pulse detectors. The pulse detectors PD1, PD2 provide logic outputs indicating whether a pulse is received.

[0054] The first and second interconnected logic comparators L1, L2 are arranged to receive the respective outputs from the first and second pulse detectors PD1, PD2. These logic comparators L1, L2 are arranged to compare the outputs from the pulse detectors PD1, PD2 with approved limits. If only one of the comparators L1, L2 detects an error, it is interconnected with the other of the comparators L1, L2, so that both logic outputs O1, O2 indicate an error. Thus, even if one of the pulse detectors PD1, PD2 fails, it will cause both logic outputs O1, O2 to indicate an error.

[0055] Therefore, only when both the first and second logic outputs O1 and O2 indicate that the first and second pulse detectors PD1 and PD2 have both detected pulse signals can the high and low gate driver parts of the drive motor driver be ensured. Therefore, the interconnection between the logic comparators L1 and L2 ensures a fail-safe function, even if only a single input signal from a single optocoupler OPT is provided to the logic comparator blocks B1 and B2.

[0056] Finally, the first and second logic gates LG1 and LG2 receive their respective logic outputs O1 and O2, and these logic gates LG1 and LG2 are arranged to allow their respective high and low gate driver outputs (H1, H2, H3, L1, L2, L3) to pass through to drive the high and low gate driver parts of the motor driver (such as an IGBT-based motor driver). The logic gates LG1 and LG2 are preferably implemented using AND gates.

[0057] In the illustrated case, three high gate driver outputs H1, H2, H3 and three low gate driver outputs L1, L2, L3 are generated to be connected to a three-phase motor driver for driving a three-phase motor. In the case of a single-phase motor and motor drive, the corresponding high and low gate driver parts only generate a single output.

[0058] Those skilled in the art will know how to implement Figure 2 the functional blocks shown and described. All components can be implemented with simple electronic parts, occupying only a small amount of space and can be implemented at low cost.

[0059] By using a single optocoupler as the electrical isolation component, the safety standard of Category 3 of EN ISO 13849-1:2015 can be obtained. The optocoupler is a bulky component and is difficult to install into the housing of a compact device. Therefore, the implementation of the safety function with a single optocoupler allows the safety function disconnect circuit to be integrated into the housing H attached to the motor MT, even when the size of the pump device is very compact, for example, a pump device with a motor MT in the electrical range of 100W or similar. However, it should be understood that the present invention is also advantageous for larger pump devices.

[0060] The safety circuit STO can preferably be implemented on a circuit board and connected to the input of the optocoupler, which is implemented on another circuit board with the components forming the motor driver. However, if desired, all these components can be implemented on one circuit board.

[0061] In summary, the present invention provides a pump device, comprising a rotary pump mechanism (P) arranged to pump fluid between a fluid inlet and a fluid outlet, and an electric motor (MT) arranged to rotationally connect a shaft to rotate the pump mechanism (P). A motor driver (MD) is connected to the electric motor MT for driving the electric motor (MT) according to a variable frequency drive scheme. A safety circuit (STO) is connected to the motor driver (MD) and has first and second electrical inputs (I1, I2) connected to external electrical switches (SW1, SW2). The safety circuit (STO) can enter a safe torque-off state to stop the electric motor MT from generating torque, and the safety circuit (STO) is designed to be redundant to enter the safe torque-off state in case of a fault, preferably conforming to Category 3 of EN ISO13849-1:2015. A housing (H) forms an outer shell in which the motor driver (MD) and the safety circuit (STO) are located. The housing (H) is attached to the electric motor MT, for example, to the conductive motor housing of the electric motor (MT). The housing (H) can partially or completely surround the electric motor (MT) and the pump mechanism (P). The pump device provides a compact pump device with an integrated safety function, allowing for easy installation in applications with safety requirements, and the pump device allows for a quick restart after a safe mode.

[0062] Although the present invention has been described in connection with the specified embodiments, it should not be construed as being limited in any way to the proposed embodiments. The scope of the present invention is defined by the appended claims. In the context of the claims, the term "comprising" or "comprises" does not exclude other possible elements or steps. References to such as "a" or "an" should not be construed as excluding a plurality. The use of reference signs of elements shown in the drawings in the claims should also not be construed as limiting the scope of the present invention. In addition, individual features mentioned in different claims can be advantageously combined, and the mention of these features in different claims does not exclude that the combination of features is not possible and advantageous.

Claims

1. A pump device, comprising a rotary pump mechanism (P) arranged to pump fluid between a fluid inlet and a fluid outlet; an electric motor (MT) arranged to rotate a shaft, wherein the shaft is connected to rotate the rotary pump mechanism (P); a motor driver (MD) connected to the electric motor and arranged to drive the electric motor (MT) according to a variable frequency drive scheme; a safety circuit (STO) connected to the motor driver (MD) and having first and second electrical inputs (I1, I2) arranged to connect respective first and second external electrical switches or contacts (SW1, SW2), wherein the safety circuit (STO) is arranged to enter a safe torque off state to stop the electric motor (MT) from generating torque, wherein the safety circuit (STO) is designed to be redundant to enter the safe torque off state in case of a fault, and a housing (H) forming an outer casing in which the motor driver (MD) and the safety circuit (STO) are located, wherein the housing (H) is attached to the electric motor (MT), such as to a conductive motor housing of the electric motor (MT).

2. The pump device according to claim 1, wherein The safety circuit (STO) includes at least one electrical isolator component (OPT) for electrically isolating the first and second electrical inputs (I1, I2) from the motor driver (MD), such as the at least one electrical isolator component (OPT) is implemented by a single optocoupler.

3. The pump device according to claim 2, wherein, The safety circuit (STO) includes a pulse generator (PG) and a modulator (MOD), wherein an output from the modulator (MOD) is connected to an input of the at least one electrical isolator component, such as the modulator (MOD) is connected to the first electrical input (I1) and an output of the pulse generator (PG); wherein the modulator (MOD) is arranged to generate an electrical output signal at a rate defined by the pulse generator (PG), the electrical output signal being a modulated version of the voltage at the first electrical input (I1).

4. The pump device according to claim 3, wherein, The pulse generator (PG) is connected to the second electrical input (I2) and arranged to generate an oscillating electrical output voltage at an output when powered from the second electrical input (I2), such as the pulse generator (PG) is arranged to generate an output voltage that switches between two levels, such that the pulse generator (PG) is arranged to oscillate at a frequency of 1 - 00 kHz, the 1 - 00 kHz frequency being such as 10 - 20 kHz, such as 14 - 16 kHz.

5. The pump device according to any one of claims 2 - 4, wherein, The safety circuit (STO) includes first and second logic comparator blocks (B1, B2), each of the first and second logic comparator blocks (B1, B2) including a pulse detector (PD1, PD2) connected to receive an electrical output signal from the at least one electrical isolator component (OPT), wherein the first and second logic comparator blocks (B1, B2) are arranged to generate respective first and second logic outputs (O1, O2) based on the outputs of their respective pulse detectors (PD, PD2), and wherein the first and second logic comparator blocks (B1, B2) are arranged to receive their respective first and second logic outputs (O1, O2) and accordingly gate their respective high and low gate driver outputs (L1, L2, L3, H1, H2, H3) for driving respective high and low gate driver sections of the motor driver (MD).

6. The pump device according to claim 5, wherein, The first and second logic comparator blocks (B1, B2) are arranged to drive the high and low gate driver sections of the motor driver (MD) only if both the first and second pulse detection outputs (O1, O2) indicate that a pulse signal has been detected by both the first and second pulse detectors (PD1, PD2).

7. The pump device according to claim 5 or 6, wherein Each of the high and low gate driver outputs includes three electrical phases.

8. The pump device according to any one of the preceding claims, wherein, The safety circuit (STO) is implemented on a circuit board and connected to the input of an electrical isolator component (OPT) such as an optocoupler, the electrical isolator component (OPT) being implemented on another circuit board together with the components forming the motor driver (MD).

9. The pump device according to any one of claims 1-7, wherein, The safety circuit (STO) and the components forming the motor driver (MD) are both implemented on a circuit board.

10. A system comprising a pump device according to any one of claims 1 - 9, and first and second switches or contacts (SW, SW2) connected to the first and second electrical inputs (I1, I2) of the safety circuit (STO), such as first and second electrical contacts positioned to detect the opening of a door or port, the first and second electrical contacts such as emergency stops, such as light curtains, such as light protection devices including proximity sensors.

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