WO2017186341A1

WO2017186341A1 - Fluid energy machine

Info

Publication number: WO2017186341A1
Application number: PCT/EP2017/000482
Authority: WO
Inventors: Wilfried-Henning Reese; Tobias Kederer; Martin BRÜCKLMEIER; Simon Schäfer; Michael WESTERMEIER
Original assignee: Linde Aktiengesellschaft
Priority date: 2016-04-28
Filing date: 2017-04-12
Publication date: 2017-11-02
Also published as: CN109072891A; KR20190002606A; US20190128246A1; JP2019515177A; EP3449123A1; DE102016005216A1

Abstract

The invention relates to a fluid energy machine, comprising a crank drive (A) and a drive device which is mechanically connected to the crank drive (A), wherein the drive device has two electric motors (M), the respective output members of which are mechanically connected to the crank drive. According to the invention, the fluid energy machine is arranged within a housing (1-5) which seals the fluid energy machine with respect to the surroundings and which is connected to a pressure-holding system. The invention also relates to a method for operating a fluid energy machine of this type.

Description

description

Fluid energy machine

The invention relates to a fluid energy machine comprising a crank drive and a drive device mechanically connected to the crank drive, wherein the drive device comprises two electric motors whose respective output members are mechanically connected to the crank drive and a method for operating this fluid energy machine.

For fueling facilities such as motor vehicles with hydrogen, which may be present in liquid form, so-called cryogenic pumps or cryogenic high-pressure pump are known, which are suitable to promote a fluid in the low temperature range.

From DE102007035616A1 a pump is known, which is designed in particular for cryogenic media. This pump comprises a piston-cylinder unit which is adapted to convey and / or compress very cold fluids, such as hydrogen.

Such pumps are usually operated with a hydraulic drive. Other conventional cryogenic pumping devices include a rotary drive instead of the hydraulic drive, which in turn is coupled to the piston of the piston-cylinder unit.

The hydraulic drive for the cryogenic pumping device usually requires a relatively large volume for housing additional units and a cooling device and a reservoir for the hydraulic fluid. Furthermore, a pump device with hydraulic drive in the installation and maintenance as well as for the measuring equipment to be installed for measuring distance in the hydraulic cylinder is relatively expensive. Usually, a linear displacement measuring system is to be arranged for this purpose. In order to avoid impermissible peak values of the volume flow to be generated, a sine-like acceleration curve of the piston is to be set in the pump device. When using a hydraulic drive device is the

Realization of a corresponding acceleration course with an increased Expenditure related to the necessary regulation and the control technology to be installed. Furthermore, can be with hydraulic

Drive devices usually no longer realize strokes of the piston-cylinder unit as having a frequency of about 2 Hz.

In the embodiment variant with electromotive drive in combination with a crank mechanism limit the maximum, frequency-dependent nominal torques of commercial electric motors, the maximum capacity of the pumping device in terms of achievable flow rate and the achievable delivery pressure. When aspiring high flow rate and high delivery pressure corresponding frequencies of the strokes and forces or moments are applied by the electric motor to the crank mechanism. This means that corresponding opposing forces acting on the electric motor or on its storage and / or on the storage of a torque-transmitting machine element between the electric motor and the crank mechanism. The stability of the bearings is to be adapted if they are not to be exposed to appropriate wear, which is particularly noticeable when the output member of the electric motor is arranged substantially coaxially to the axis of rotation of the crank mechanism and is firmly connected to this crank mechanism.

A fluid machine which is capable of overcoming the disadvantages comprises a crank mechanism and a drive device mechanically connected to the crank mechanism, with which a torque can be introduced into the crank mechanism. Furthermore, the fluid energy machine comprises a piston-cylinder unit whose piston is mechanically connected to the crank mechanism. It is provided that the drive device comprises two electric motors whose respective output members are mechanically connected to the crank mechanism. Furthermore, it is provided that the piston-cylinder unit comprises only one piston and only one cylinder. The electric motors, hereinafter also referred to as motors for short, are rotatory motors, whereby the arrangement of more than two motors should not be excluded. The drive device thus comprises at least two motors.

An advantage of such a fluid energy machine is that, despite slower speeds of the shaft, it works from 1 to 600 revolutions per minute (rpm) and nevertheless can achieve the necessary high pressures. Despite the slow

Speeds can use the electric motors high torque in the range of 1000 Up to 8000 Nm, in particular up to 4000 Nm, can be achieved. The resulting on the

The force exerted on the piston rod is 10 to 150 kN, in particular 15 to 20 kN. Through the connection of two motors to the crank mechanism a symmetrical load and a distribution of the counter-forces or counter moments on the two motors or their drive shafts is achieved, which reduces the overall load and / or wear on the drive device or the crank mechanism can be. The bearings can be dimensioned correspondingly smaller, or the waves can be run with a smaller diameter. A disadvantage of such a fluid energy machine is that the installation in

Category I and II explosion protection zones are not possible due to the availability of suitable electric motors currently available on the market. However, this is especially important for the promotion of hydrogen and other combustible substances.

The object of the invention is to provide a fluid energy machine and a method for operating a fluid energy machine, which can be used in explosion protection zones of category I and I I.

The object is achieved on the device side in such a way that the fluid energy machine is set up within a housing which seals the fluid energy machine from the environment and which is connected to a pressure maintenance system.

Advantageously, water-cooled electric motors are used as electric motors. As a result, no air supply for cooling the motors is necessary and the sealing of the housing is easier to implement.

In terms of the method, the object is achieved such that the fluid energy machine is set up within a housing through which a pressure medium flows. The housing is preferably a force-bearing housing.

Preferably, the housing is divided into several rooms, the rooms are in communication. Advantageously, the spaces are connected in series. Preferably, the spaces are flowed through successively by the pressure medium. In a preferred embodiment variant, the housing is subdivided into three or five spaces, wherein a first space surrounds the crank drive and a passage for connecting the crank drive to a piston-cylinder unit is provided. All bushings of the housing are known to those skilled in the art

Sealing sealed against the environment. In particular, covers, sealing grooves with sealing rings, adhesive seals and sealed screws can be used for this purpose.

Two other rooms each represent the outer space of the respective electric motor. In particular, the respective magnets, coils and the

Power electronics housed. These rooms are in particular

Bushings for cooling and power supply as well as control and regulation technology. Another two rooms form in a preferred embodiment, the respective inner space of the two electric motors. Within these rooms is the connection of the respective shaft for power transmission of the respective motor. These spaces are sealed off from the atmosphere by additional covers with special gaskets and allow the passage of the waves. However, the electric motors may be arranged in another preferred embodiment only within a room.

The housing is in particular designed so that an overpressure between 0, 01 and 50 mbar, in particular of 2.5 mbar can be created. This means that the seals for sealing all bushings are designed so that at an overpressure of 0.01 and 50 mbar, in particular of 2.5 mbar, inside the housing compared to the environment of the fluid energy machine, no

Pressure medium emerges. The overpressure can also be realized in a preferred embodiment in a sealed against the environment housing when no constant flow takes place.

Advantageously, the housing communicates via an inlet and an outlet with the pressure-retaining system. Preferably, the inlet is arranged on the first space and the outlet is installed on the last, in particular the fifth space. The rooms communicate with each other through holes that all

Cavities are interconnected and can be traversed by a pressure medium.

Advantageously, an overpressure of the pressure medium is maintained by the pressure holding system. The pressure holding system is preferably a compressor station or a Bundles of cylinders. If pressure medium escapes from the housing into the environment as a result of slight leakage and there is thus a loss of pressure medium, the pressure retaining system can introduce new pressure medium. Thus, advantageously, the pressure medium does not have to flow continuously through the housing, but preferably new pressure medium can only ever be added if the overpressure in the housing falls below a predetermined value.

The pressure medium used is advantageously air, nitrogen or another inert gas. The pressure medium flows preferably at an overpressure between 0.01 and 50 mbar, in particular at 2.5 mbar through the housing.

Due to the overpressure, no reactive mixture can flow from the outside into the housing, so that the electric motors, which represent potential sources of ignition, are protected, and thus the fluid energy machine can be set up and used in explosion protection zones.

Advantageously, sensors may be provided within the pressure-maintaining system and / or within the housing to monitor the pressure of the pressure medium. Should the deviation of the pressure from a predetermined value be detected, for example a pressure loss, this indicated a leakage. The sensors are advantageously in connection with the electric motors, so that they can be switched off and de-energized. Thus, the electric motors would no longer be an ignition source.

In addition, sensors may be provided which detect traces of the medium to be conveyed within the pressure medium in order to determine a leakage within the housing. Thus, even slight leaks of the medium to be pumped by the fluid energy machine can be detected. In addition, the most inflammable medium to be delivered is diluted by the pressure medium and out of the system

discharged. The risk of explosion can be reduced.

The fluid energy machine may exceed a predetermined one

Limit value to be stopped.

After a standstill of the fluid energy machine and / or the pressure maintenance system, the system is preferably for a certain time, in particular 2 to 5 minutes, rinsed with an increased flow of the pressure medium to remove any impurities. Advantageously, the fluid energy machine is used to generate a hydrogen volume flow and to compress hydrogen. It is preferred for refueling a vehicle with liquid or gaseous

Used hydrogen. The hydrogen is compressed to a system pressure of 50 to 1000 bar, in particular 350 to 500 bar or 700 or 900 bar. Preferably, the delivery rate of the hydrogen is adjusted via the frequency of the electric motors, so that it is between 0 and 250 kg / h, in particular between 30 and 200 kg / h.

In the following, the invention will be explained in more detail with reference to an exemplary embodiment shown schematically in FIG.

FIG. 1 shows a schematic embodiment of the invention

Contraption. Shown is the housing of a high pressure pump in

explosion-proof version. The pump is suitable for cryogenic fluids, in particular for hydrogen.

The housing is divided into the rooms 1 to 5, wherein the rooms communicate with each other. Room 1 encloses the crank drive A. Space 2 and space 4 each represent the outer space of the respective electric motor M. In particular, the respective magnets, coils and the power electronics are in these

accommodated. Room 3 and room 5 form the respective inner space of the two electric motors M. Within these spaces is the connection of the respective shaft for power transmission of the respective motor. These rooms are sealed off by additional covers W with special seals against the atmosphere.

All cavities within the respective spaces are through holes

fluidically accessible. Thus, all cavities within the housing are achieved by a pressure medium and can be rinsed.

Through the supply for the printing medium E, which is arranged in this embodiment in space 1, a pressure medium is introduced into the housing. The pressure medium flows through all rooms 1 to 5 in succession and is returned to room 5 via an outlet D back to the pressure holding system. The pressure holding system is designed to maintain the pressure medium at a pressure of 2.5 mbar. If pressure medium escapes into the environment due to small leaks, pressure medium can be supplied in the pressure holding system. If a pressure drop in the pressure holding system is detected or too high

Hydrogen content detected within the pressure medium is carried out an emergency shutdown. The motors are stopped and de-energized. Thus, the engines are no longer an ignition source. After appropriate maintenance, the system can be restarted.

During startup, or the start of the pressure holding system after a standstill, the pressure holding system for a certain time, in particular 2 min flushed with an increased mass flow of the pressure medium. If, during standstill, hydrogen has leaked from the pump or lines into the housing, it will be removed or at least diluted.

Claims

claims

Fluid energy machine, comprising a crank mechanism and a drive device mechanically connected to the crank mechanism, wherein the

Drive device comprises two electric motors, their respective

Output members are mechanically connected to the crank mechanism, characterized in that the fluid energy machine is arranged within a housing which seals the fluid energy machine from the environment and which communicates with a pressure-maintaining system.

Fluid energy machine according to claim 1, characterized in that the housing is divided into a plurality of spaces, wherein the spaces communicate with each other.

Fluid energy machine according to claim 1 or 2, characterized in that the housing communicates via an inlet and an outlet with the pressure-retaining system.

Fluid energy machine according to claim 1 or 2, characterized in that the housing is designed so that an overpressure between 0.01 and 50 mbar, in particular of 2.5 mbar can be applied.

A method of operating a fluid energy machine comprising a crank mechanism and a crank mechanism mechanically connected

Drive device, wherein the drive device comprises two electric motors whose respective output members are mechanically connected to the crank mechanism, characterized in that the fluid energy machine is arranged within a housing, which is flowed through by a pressure medium.

A method according to claim 5, characterized in that air, nitrogen or another inert gas is used as the pressure medium.

7. The method according to claim 5 or 6, characterized in that the

Pressure medium at an overpressure between 0.01 and 50 mbar, in particular at 2.5 mbar flows through the housing.

8. The method according to any one of claims 5 to 7, characterized in that the overpressure of the pressure medium is maintained by a pressure holding system.

9. The method according to any one of claims 5 to 8, characterized in that the housing is divided into a plurality of spaces, which together in

Connection and which are flowed through by the pressure medium in succession.

10. The method according to any one of claims 5 to 9, characterized in that the fluid energy machine is used to generate a hydrogen volume flow and / or for the compression of hydrogen.