Device for the dosing of lubricants

In a device for the dosing of lubricants which comprises at least one manual throttling element limiting the volume flow and a flow metering device connected downstream of it, which contains at least one sensor element movable through the volume flow, a dynamic flow metering means (M) is connected downstream in the manual throttling element (D) whose sensor element (S) moves also after the reaching of the nominal volume flow and a display means (A) is provided on the dynamic flow metering device (M), which represents the actual volume flow from the movement of the sensor element (S).

BACKGROUND 
1. Field of the Invention 
The present invention relates to apparatus for supplying measured doses of 
lubricants to a lubricating line. In particular, the present invention 
relates to devices for dosing lubricants to a lubricating line wherein the 
devices of the type having at least one manual throttling element limiting 
the volume flow of the lubricant into the lubricating line. 
2. Description of the Prior Art 
Such dosing devices with manual throttling element are used for specific 
central lubrication tasks in the parallel distribution of lubricant flows 
depending upon the requirements of the machine manufacturers or operators. 
The manual adjustability of the manual throttling element is necessary in 
practice to reduce the volume flow for a specific period of time in the 
case of cold, highly viscous lubricants and to prevent an overflow of 
lubricating points in the case of a reflux which is still deficient due to 
the viscosity. A machine-load-dependent lubricant dosing is adjusted in 
each case in a relatively simple fashion. Relatively large volume flows up 
to about 6 1/min. are dosed to the lubricating points in body presses, 
large transmissions and paper machines. 
In the dosing device known from the print sheet No. 01 80.03.86 of Eugen 
Woerner GmbH & Co., D-6980 Wertheim the flow metering device is an 
inspection pipe with a floating piston as sensor element, whose position 
determined by the volume flow is electrically monitored. The boundary 
values of the volume flow are entered on a scale. An LED display serves 
for the function control by indicating whether the floating piston has 
reached or exceeded a previously determined position in the inspection 
pipe. 
The, dosing device according to the publication "Durchflu.beta.messer", 
48715 PB1 of the DE LIMON FLUHME GmbH & Co. company, D-4000 Dusseldorf 1 
works according to the same principle, an electric switching contact being 
actuated as a function of the position of the floating body. 
These dosing devices work in a strongly viscosity-dependent fashion, i.e. 
they must be calibrated at a specific lubricant temperature. Static flow 
metering devices are concerned since the floating body remains immovable 
under the adjusted volume flow during operation. Several disadvantages 
result from this. Due to impurities contained in the lubricant and 
substances deposited e.g. due to the additives under thermal and 
mechanical load, the inspection pipe becomes clogged. A direct visual 
control of the position of the floating body is rendered difficult or even 
impossible after a longer service life. The floating body often remaining 
immovable for weeks gets caught due to such deposits and delivers then an 
"erroneous" "okay" message despite a changing volume flow. These 
impurities change the flow cross-sections near the floating body so that 
it changes its position and generates a "erroneous" fault signal, although 
the volume flow is correct or still within an admissible tolerance range 
or generates an "erroneous" "okay" signal although the volume flow is no 
longer correct. A serious disadvantage of these static flow metering 
devices is moreover the incorrect display of the volume flow and the 
difficult exact calibration. This is also due to the fact that the 
floating body only indicates whether the nominal volume flow has been 
reached or not reached or exceeded. In lubricating systems in which such 
relatively inexpensive throttling dosing devices which are easy to handle 
are used, this has been put up with so far as being inevitable and it was 
attempted by means of frequent controls and knocking against the 
inspection pipe to ensure a proper function and to avoid damages in the 
lubricating points. Therefore it has become a custom to let supervisors 
control all dosing devices practically daily although the adjusted volume 
flow is not changed for weeks or months. 
Dynamic flow metering devices are known per se. According to DE-OS 29 43 
184 a flow metering cell for a flowing liquid contains a gearwheel or an 
impeller, whose rotational speed is inductively scanned to detect the 
actual flow. The wheel may consist of plastic material and be equipped 
with permanent magnets. This principle is not suited for relatively 
viscous lubricants. An oval wheel meter serving as flow counter with an 
electric pulse transmitter on a wheel serves for determining the oil 
consumption of an oil burner according to DE-OS 35 11 537. 
SUMMARY OF THE INVENTION 
The invention is based on the object of creating a device of the type 
mentioned at the beginning which distinguishes itself by an increased 
operational reliability and a greater accuracy of dosing maintaining the 
advantage of constant manual adjustability and direct control at the 
adjustment point. 
In accordance with the present invention as embodied and broadly described 
herein, a device as a constructional unit for the dosing of lubricants to 
at least one lubricating point connected to a throttling line comprises at 
least one manual throttling element limiting the volume flow to the 
lubricating point and a flow metering device connected downstream of the 
manual throttling element. The flow metering device contains at least one 
sensor element movable through the volume flow. The flow metering device 
is a dynamic flow metering device connected downstream of the manual 
throttling element and whose sensor element also moves during constant 
volume flow. The device further includes a display device showing the 
actual volume flow from the movement of the sensor element. 
The dynamic flow metering device of the present invention which will be 
described in more detail hereinafter works with a self-cleaning effect, 
because movements of the sensor element take place even in the case of a 
volume flow remaining unchanged in the flow metering device, which prevent 
the depositing of impurities and the partial clogging of the flow metering 
device. The respective actual volume flow is exactly indicated from the 
movement of the sensor element. If a foreign matter gets into the dynamic 
flow metering device, it can possibly block or decelerate it, which is, 
however, immediately indicated. There is neither a "erroneous" "okay" 
display nor a "erroneous" fault display. This increases operational 
reliability, because it is definite at all times that the actual volume 
flow is correctly displayed in the case of all conditions, i.e. also in 
the case of failures, which excludes an erroneous alarm as well as 
uncertainties due to "erroneous" "okay" messages. Since the display means 
in the constructional unit permanently keeps on hold an indication derived 
from the dynamics of the sensor element so-to-speak on site, the volume 
flow can be directly controlled more exactly at the adjustment element of 
the manual throttling element and is above all displayed more correctly 
than in a static flow metering device, which depends on a static position 
depending on many influences. The robust and inexpensive device which is 
actually simple due to the manual throttlling element becomes a precise 
device for such high requirements due to the dynamic flow metering device, 
the fulfilling of which has only been possible so far with substantially 
more expensive apparatus structures, such as an expensive and sensitive 
flow limiter. Nevertheless, the device maintains the advantage of simple 
construction and adjustability at all times, because, strictly speaking, 
intervention is only carried out on the monitoring side and the accuracy 
and reliability of the monitoring of the effected adjustment is increased. 
The dynamic flow metering device has furthermore the important advantage 
of working largely viscosity-independent as opposed to static flow 
metering devices which work in an extremely viscosity-dependent fashion 
and can only be correctly adjusted to a certain extent in the case of the 
actual operating temperature of the lubricant and which do not longer 
display correctly in the case of changes in the temperature. 
It is certainly known in lubricant technology to use relatively expensive 
flow limiters working proportionally in exacting lubricating problems. 
Each flow limiter is alone responsible for adjusting and observing the 
volume flow. A dynamic flow metering device can be connected downstream of 
these flow limiters, which is connected to a central measuring station. In 
the measuring station a function control is associated to each dynamic 
flow metering device and possibly even a display or comparator means. A 
direct visual control on site and on the dynamic flow metering device is 
only possible by means of visual control of the movement of the sensor 
element. However, the visual control only confirms the flowing of a volume 
flow without giving information on its actual dimensions. For this reason 
dynamic flow metering devices have so far only been used in lubricating 
technology in connection with flow limiters such as in DE-OS 28 24 353, in 
which a volume controlling valve separated from the dynamic flow metering 
device designed as gearwheel motor is provided as flow limiter and the 
actual amount is displayed via a transmission from a separately disposed 
display means. 
Preferably, the dynamic flow metering device is a gear wheel motor with two 
permanently engaged spur wheels whose engagement area is in a measuring 
chamber and that the flow path for the volume flow extends in tangential 
direction of the spur wheels through the engagement area. The spur wheels 
being in engagement are already driven in the case of small volume flows 
so that the exact indication of the actual volume flow can be read. Each 
adjustment of the manual throttling element can be immediately read on the 
display means so that an exact adaption to the nominal volume flow becomes 
possible. If a foreign matter gets into the engagement area of the spur 
wheels, their movement is hindered or blocked, which ensues in an fault 
signal. In the case of a volume flow being unchanged for a long period of 
time the spur wheels produce a desirable self-cleaning effect, which 
eliminates the susceptibility to failures due to deposited impurities. If 
deposits narrow the passage, this is also displayed immediately. If the 
spur wheels are blocked then the fit ensured by the backlash of the teeth 
and the mobility of the gearwheels in the measuring chamber is sufficient 
for an emergency running, although there is already a failure display. The 
difference in pressure produced by the spur wheels is negligible and does 
not have any noticeable influence on the uniform supply of the 
luburicating point. The manual throttling element alone is responsible for 
adjusting and observing the volume flow. Since the gearwheels convey 
exactly predetermined individual volumes during their movement, which are 
exactly counted, the display is extremely accurate. Changes in the 
viscosity caused by the temperature do not have any noticeable influence 
on the accuracy of the display, because the same volumes are always 
conveyed. The display is always correct independently of the temperature 
of the lubricant. 
It is also preferred that at least one permanent magnet is contained in at 
least one of the spur wheels, that a scanning means is provided with at 
least one scanning element aligned to the circumferential path of the 
permanent magnet, and that the scanning means is connected to the display 
means via an evaluator circuit. The gearwheel motor has here the function 
of a drive for the permanent magnets, whose movement is ascertained by the 
scanning means and can be converted to a display value representing the 
actual volume flow via the evaluator circuit. The conversion of the 
movement of the spur wheels can be effected both digitally or analoguely. 
The useful signals from the rotating movement of two oppositely polarized 
permanent magnets are exact and can be well processed to exactly indicate 
the volume flow. Not only each change of the volume flow is displayed, but 
also a volume flow being constant over long service lives. 
It is still further preferred that the scanning means, the evaluator 
circuit, and the display means are disposed on the housing of the gear 
wheel motor and that a separate power supply for the scanning means, the 
evaluator circuit, and the display means is provided, and also that the 
display means is operatively connected in signal-transmitting relationship 
to an external measuring station. The display means can contain an LCD or 
LED display. The additional connection to the measuring station permits a 
remote control of the dosing device, although it displays failures in 
clearly visible fashion at all times for a direct control and represents 
the volume flow, which is required for the correct adjustment by means of 
the manual throttling element. The LCD or LED displays work reliably and 
insusceptibly to failures over long service lives with low energy 
requirements. 
It is also preferred that the display means includes an alarm signal 
transmitter. This is furthermore important because the alarm signal 
transmitter displays failures which can then be eliminated immediately. A 
daily visual or knock control of the dosing device is superfluous, because 
the control persons can rely on the precision of the dynamic flow metering 
devices, since they are insusceptible to failures due to impurities or 
foreign matter inasmuch as they exactly display failures and to not emit 
any erroneous fault signals or erroneous "okay" signals. 
And it is yet still further preferred that a plurality of dynamic flow 
metering devices are disposed in group-like fashion on a joint base plate 
containing a lubricant supply line and branch connections to lubricating 
lines so that the displays of the display means are at the same side, 
preferably the side of the manual throttling elements. At least one 
adjustable manual throttling element is disposed in the base plate between 
the lubricant supply line and each branch connection. The manual 
throttling element can be built into the housing of the gear wheel motor, 
and the scanning means, the evaluator circuit, and the display means can 
be disposed on the housing as an exchangeable module. The multiple device 
feature is significant in that a minimum of space need be utilized to 
monitor a lubricant flowing to several different lines. These features are 
furthermore important because the modular construction is advantageous in 
view of repairs or maintenance work and corresponds to modern construction 
concepts. The monitoring system of each dosing device is independently 
designed in customary fashion so that it emits an alarm signal during a 
failure, the display means possibly working with a failure coding, so that 
the respectively occurred failure is displayed and can be rapidly 
eliminated. If a failure occurred for instance in one of the components of 
the dosing device, e.g. a mechanical defect in the gearwheelmotor or a 
shortcircuit in one of the electrical or electronic components, then the 
faulty component can be rapidly replaced as a modular component. Here, as 
well, the dynamic flow metering device can bring to bear its 
characteristic given due to the dynamics to be able to differentiate 
between different failure causes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
For the parallel distribution of large volume flows of lubricant a group B 
of dosing devices Z for at least one lubricating point in each case is 
provided according to FIGS. 1 and 2, each dosing device Z representing a 
constructional unit of its own in the group B. A manual throttling element 
D serves for adjusting the volume flow, to which a dynamic, optoelectronic 
flow metering device M is connected downstream in the direction of flow. 
At least one sensor element S is provided in the flow metering device M, 
which can be moved through the volume flow of lubricant. A scanning means 
T is associated to the sensor element S, which is connected to a display 
means A via an evaluator circuit 15. 
In a base plate 1 common to all provided dosing devices Z, which contains a 
central supply line 2, several branch lines 3 fork of from the same. The 
inflow to each branch line 3 is adjusted by the manual throttling element 
D. It has a locking screw 4 for the throttling element 6, which is screwed 
into a threaded bore 5, which cooperates in customary fashion with a 
receiver 7. An axial screwing of the throttling element 6 effects a change 
of the throttle cross-section and thus of the volume flow in the 
lubricating line. 
A housing 8 of the dynamic flow metering device M which is allocated to the 
manual throttling element D is screwed onto the base plate 1. A gearwheel 
motor 9 with two permanently engaging spur wheels 21, 21a is provided in a 
measuring chamber 12 in the housing 8. A connection 10 leads from the 
branch line 3 to the measuring chamber 12. A connection 11 serves for 
connecting the lubricating line. The connection 11 could also end in the 
base plate 1, to which the lubricating line is then connected. At the 
inspection side of the flow metering device M the measuring chamber 12 is 
closed by an inspection glass 13 which is sealingly fixed to the housing 8 
by means of a retaining ring 23. A scanning element 14 is held in a 
housing bore 28 which extends in parallel to the rotational axis of the 
two spur wheels 21, 21a, which is part of the scanning means T. The 
scanning element 14 is in a signal-transmitting connection with the 
evaluator circuit 15, which is built into the housing 8, which is supplied 
with current via a line 16a and a plug 16. The evaluator circuit 15 is 
furthermore in signal-transmitting connection with the display means A, 
which has a display 18 (LED or LCD display) at the inspection side of the 
inspection glass 13 of the housing 8. The evaluator circuit 15 or the 
display means A is connected with a measuring station W locally separated 
from the dosing means Z via a line 16b. 
The spur wheels 21, 21a are rotatably mounted in the bottom 20 with 
plug-type axles 19. The spur wheel 21 serves as a driving element for 
diametrally opposite axis-parallel permanent magnets 22 with opposite 
polarities. The scanning element 14 is aligned to their orbits. Several 
scanning elements may also be provided for a higher resolution. 
The spur wheels 21, 21a support a radial toothing 24 and have a joint 
engagement area 25 approximately in the centre of the measuring chamber 
12, through which the volume flow flows from the connection 10 to the 
connection 11 approximately tangentially to both spur wheels 21, 21a. The 
measuring chamber 12 has an approximately kidney-shaped contour with two 
opposite swells 26, into wich part of the circumference of each spur wheel 
21, 21a is fitted with small backlash. The inspection glass 13 and the 
bottom 20 of the measuring chamber 12 are in alignment with the front 
sides of the two spur wheels 21, 21a so that the lubricant is forced to 
flow to the engagement area 25. Since the pressure reduction by means of 
the swells 26 is effected in a different fashion than via the meshing 
teeth in the engagement area 25, the gearwheel motor 9 is driven in such 
fashion in FIG. 2 that the lower spur wheel 21 is rotated clockwise and 
the upper spur wheel 21a is rotated counter-clockwise. The scanning 
element 14 is suitably a Hall sensor which is activated as a function of 
the rotational speed of the spur wheels 21, 21a and emits useful signals. 
The signals are processed in the evaluator circuit 15. The display on the 
actual volume flow appears constantly in the display field 18 of the 
display means A. The signals of the evaluator circuit 15 or also of the 
Hall sensor 14 can be transmitted to the measuring station W via line 16b. 
The actual condition is continuously represented and compared with a 
nominal value for all partial volume flows in the measuring station. 
A signal transmitter 27 is mounted on the display means A, which is either 
activated from the measuring station W or via the evaluator circuit even 
in the case of a failure, e.g. in the case of an inadmissible exceeding of 
or dropping below the nominal volume flow. The display means A could also 
work with an failure coding, by means of which the respective cause of the 
failure is displayed in coded form. For this purpose the evaluator circuit 
15 could be equipped with a comparator, which can be adjusted at the 
dosing device Z by inputting parameters when required. 
The display means A could be built into the housing 8. It is furthermore 
conceivable to build the manual throttling element D also into the housing 
and to design the individual components, i.e. both the manual throttling 
element, the scanning means T, the evaluator circuit 15 and the display 
means A as modules which can be exchanged, if required. As a further 
possibility the base plate 1 could be divided into sectors, one sector 
each being integrated into the housing 8. Then, too, the group-like 
joining of several dosing devices on a minimum of space is possible. 
Nevertheless, the possibility is preserved to check each dosing device 
optically already by a glance to the inspection glass 14 as regards 
function and by a glance to the display 18 as regards the volume flow. 
Upon the adjustment of the manual throttling element D, it can be 
immediately detected at all times on the display 18 how the volume flow is 
changed. This is suitable if e.g. during the starting phase of a machine 
an overflooding of the lubricating points must be avoided in the case of a 
viscosity-inherent and still deficient reflux of the lubricant or if an 
adaptation to the machine load is effected in the case of a 
machine-load-dependent dosing changing the volume necessary for normal 
operation. The manual throttling element D could also be composed for a 
coarse and a fine throttle. 
The spur wheels 21, 21a consist suitably of a non-magnetic material, e.g. a 
plastic material, which is dimensionally stable and resistant against the 
lubricant and has good endurance run properties. Due to the running 
movement of the two spur wheels 21, 21a the inspection glass 13 is 
automatically freed from impurities settling from the lubricant. Thermally 
highly loaded lubricants such as oils tend to deposit additives or 
impurities resulting from the reaction between additives and other 
substances in the case of long service lives. These deposits can narrow 
the flow ducts in the extreme case. The gearwheel motor 9 is insusceptible 
to such influences and works independently of viscosity in a desirable 
fashion. Several gearwheel motors may also be accommodated in one and the 
same housing. Since the display 18 anyhow displays the proper function of 
the gearwheel motor besides the exact indication of the actual volume 
flow, the inspection glass could be omitted and the housing could be 
designed in closed fashion, which possibly ensues in production-technique 
advantages.