Grease collection arrangement

Abstract

Provided is a grease collection arrangement for collecting waste grease from a bearing, including a plurality of grease extraction valves, wherein each grease extraction valve is connected to a grease outlet of the bearing, an extraction line extending from each grease extraction valve to a common extraction line, a vacuum apparatus configured to create an under-pressure in the extraction lines, and a control module configured to selectively open and close a grease extraction valve. Also provided is a method of collecting waste grease from a bearing lubrication circuit using the grease collection arrangement.

Claims

1. A grease collection arrangement for collecting waste grease from a bearing, comprising: a plurality of grease extraction valves, wherein each grease extraction valve is connected to a grease outlet of the bearing; a plurality of extraction lines, each extraction line extending from one of the plurality of grease extraction valves and converging to a common extraction line; a vacuum apparatus comprising a vacuum pump and a vacuum chamber arranged in the common extraction line, configured to create an under-pressure in the extraction line and the common extraction line, wherein the vacuum pump, when actuated, progressively withdraws air from the common extraction line, and the vacuum chamber comprises a first chamber at a first side of the vacuum chamber, a second chamber at a second side of the vacuum chamber, and a membrane to separate the first chamber from the second chamber and to ensure that grease remains within the first chamber on the first side of the vacuum chamber, the first chamber including an inlet fed by the common extraction line and an outlet leading to a waste grease reservoir; a first valve arranged in the common extraction line, upstream from the vacuum chamber; a second valve arranged between the vacuum chamber and the vacuum pump that is selectively closed to maintain the under-pressure in the vacuum chamber; a third valve positioned between the vacuum chamber and the waste grease reservoir; and a control module configured to selectively open and close a grease extraction valve of the plurality of grease extraction valves, wherein, when the grease extraction valve is open, the first valve is open to suck grease into the common extraction line, and when the first valve is closed, the third valve is opened and the vacuum pump alters a running direction to create an overpressure in the first chamber of the vacuum chamber to force the grease out of the first chamber and into the waste grease reservoir.

2. The grease collection arrangement according to claim 1, wherein the first chamber is arranged between the common extraction line and the waste grease reservoir.

3. The grease collection arrangement according to claim 1, comprising a flow-meter arranged in the common extraction line.

4. The grease collection arrangement according to claim 1, further comprising at least 16 grease extraction valves.

5. A wind turbine rotor blade pitch assembly comprising: a pitch bearing comprising a plurality of grease outlets for a removal of lubricant grease; a lubrication system configured to deliver lubricant grease through a lubrication circuit to the pitch bearing; and the grease collection arrangement according to claim 1 for extracting waste grease through the plurality of grease outlets of the pitch bearing.

6. The wind turbine rotor blade pitch assembly according to claim 5, wherein the plurality of grease outlets are provided in a stationary raceway of the pitch bearing.

7. The wind turbine rotor blade pitch assembly according to claim 5, wherein the lubrication system is a progressive lubrication system.

8. The wind turbine rotor blade pitch assembly according to claim 5, wherein a grease depository is arranged in an interior of a wind turbine hub.

9. A method of collecting waste grease from a bearing lubrication circuit using the grease collection arrangement according to claim 1, the method comprising: closing the plurality of grease extraction valves; actuating the vacuum apparatus to create the under-pressure in the extraction line and the common extraction line; and opening a grease extraction valve to allow passage of waste grease into the common extraction line.

10. The method according to claim 9, wherein only one grease extraction valve is opened at any one time.

11. The method according to claim 9, further comprising identifying a grease extraction valve positioned in a critical region of the bearing, and more frequently opening that grease extraction valve.

12. The grease collection arrangement according to claim 1, wherein the plurality of extraction lines converge to the common extraction line from more than two different circumferential locations along the bearing.

13. The grease collection arrangement according to claim 1, wherein the plurality of extraction lines includes more than two extraction lines that converge to the common extraction line.

Description

BRIEF DESCRIPTION

(1) Some of the embodiments will be described in detail, with references to the following Figures, wherein like designations denote like members, wherein:

(2) FIG. 1 shows an embodiment of a grease collection arrangement;

(3) FIG. 2 shows components of a progressive lubrication system;

(4) FIG. 3 shows a prior art bearing lubrication system; and

(5) FIG. 4 shows a prior art bearing lubrication system.

DETAILED DESCRIPTION

(6) FIG. 1 shows an embodiment of the grease collection arrangement 1. The diagram indicates a rotor blade pitch bearing 2 with a number of grease outlets 20 through which lubricant grease can be removed.

(7) In the grease collection arrangement 1, waste grease is extracted under vacuum. To this end, the grease collection arrangement 1 comprises a number of individually controllable grease extraction valves 10V, one at each grease outlet 20. Each grease extraction valve 10V is connected to a waste line 10L, and these all feed into a common line 10N. The common line 10N leads to a waste grease container 15, via one chamber 12A of a vacuum chamber module 12. Only four grease outlets 20 are shown in the diagram for the sake of clarity, and therefore only four grease extraction valves 10V and waste lines 10L, but it shall be understood that the stationary race of a large pitch bearing may be provided with 20-30 such grease outlets 20, and the inventive grease collection arrangement 1 will also have a corresponding number of grease extraction valves 10V and waste lines 10L.

(8) Each grease extraction valve 10V is controlled by a signal 13-1, 13-2, . . . , 13-n issued by a control module 13. While all grease extraction valves 10V are closed, the control module 13 actuates a pump 11 that progressively withdraws air from the common line 10N and the waste lines 10L, via the second chamber 12B of the vacuum chamber module 12.

(9) When the pressure in the extraction circuit has been reduced to a desired low level, valve 16 is closed in order to maintain the under-pressure in the chamber 12. A selected grease extraction valve 10V is opened by issuing an appropriate control signal. For example, the grease extraction valve 10V on the right side of the bearing 2 in the diagram is opened by signal 13-1. At the same time, valve 17 is opened. Any waste grease at the outlet 20 of the selected grease extraction valve 10V will be sucked into the common line 10N by the under pressure at the vacuum chamber 12.

(10) Waste grease in the common line 10N passes through the first chamber 12A to the grease container 15. A membrane 12M ensures that grease remains on the one side of the vacuum chamber module 12. As the waste grease arrives in the secondary chamber 12A, valve 17 is closed, and valve 18 is opened. The vacuum pump 11 then alters its running direction in order to generate an overpressure in the primary chamber 12A, with the result that the waste grease is forced out of the primary chamber 12A and into the waste grease reservoir 15.

(11) The diagram also shows a flow-meter 14 arranged in the common line 10N. The flow-meter 14 measures the quantity of extracted grease. The data collected and reported by the flow-meter 14 can be reported back to a control center and/or recorded for readout during a service routine. FIG. 2 shows components of a progressive lubrication system 3 which can be used to provide lubricant grease to a device such as a rotor blade pitch bearing (not shown). Lubricant grease is provided in a reservoir pump unit 30 that pumps the grease to a primary metering device 31, which in turn distributes the grease to a number of secondary metering devices 32 (two are shown here by way of example). Each secondary metering device 32 has a number of outlets connected by branch lines 32-1, 32-2, . . . , 32-n to grease entry points of the pitch bearing. The metering devices 31, 32 ensure that predetermined quantities of lubricant arrive at the grease entry points. The amount to be metered is determined by a control unit 33. Such a progressive lubrication system provides continuous lubrication when the pump is in operation. If the pump is halted, the pistons in the metering devices 31, 32 hold their positions, and resume from those positions when the pump is re-started.

(12) FIG. 3 shows a prior art bearing lubrication system 5, in this case a single-line lubrication system. Here, grease is provided from a grease supply 50, and a number of grease injection modules 51 are used to inject lubricant grease into a bearing 2. Waste grease passes from a waste outlet 52 into a common line 54 that feeds into a container 55. However, a problem with this arrangement is that the waste grease collection is driven by the amount of grease added. Grease collection is therefore only done when lubricant grease is replenished. If any hose of the lubricant circuit becomes faulty for any reason, the entire system is compromised and the pitch system must be halted for repair.

(13) FIG. 4 shows another prior art single-line lubrication system 6 for a rotor blade pitch bearing. Here, grease is provided from a grease supply 60, and waste grease passes from a waste outlet 62 of a single-line ejector 61 into a common line 64 that feeds into a container 65. In this case also, the waste grease collection is driven by the amount of grease added, and waste grease is only collected when lubricant grease is replenished.

(14) Although embodiments of the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of embodiments of the invention.

(15) For the sake of clarity, it is to be understood that the use of a or an throughout this application does not exclude a plurality, and comprising does not exclude other steps or elements.