NZ214455A - Cutting bit fluid cooling nozzle with blockage protection - Google Patents

Description

^r-Hss* PATENTS FORM NO: 5 PATENTS ACT 1953 COMPLETE SPECIFICATION "DEVICE FOR SPRAYING COOLING LIQUID FORM THE NOZZLES OF A'CUTTING HEAD" WE, VOEST-ALPINE Aktiengesellschaft of A-4O2O Linz, Muldenstrasse 5, Austria a stock company organised and existing under Austrian law hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement (followed by page la) 21445 DEVICE FOR SPRAYING COOLING LIQUID FROM THE NOZZLES OF A CUTTING HEAD BACKGROUND OF THE INVENTION Field of the Invention The invention refers to a device for spraying cooling liquid from the nozzles of a cutting head being equipped with bits and being rotatably supported on a cutting arm, in which device the cooling liquid can be supplied to the nozzles via passages within the interior of the cutting head, in particular with interposition of valves actuable by the bits and/or of a sector control. In particular when using a sector control or when subjecting the nozzles with cooling liquid in dependence on the load of the bits, it is not easily visible for the machine driver whether the nozzle associated to one bit actually sprays liquid to the cutting face during that time interval during which the bit is in engagement with the rock to be excavated. On account of the dust-loaden atmosphere in proximity of the cutting face, it is easily possible that the nozzles become clogged by fine dust and do not supply cooling liquid during the critical movement of engagement of the bit with the rock. \ Such clogging of the nozzles may, however, have as a result^ that inadmissibly high temperatures occur at the cutting face and that, therefore, sparking and explosions are possible. - y,.... ,y<..

V , ':i!'? .v.r 21J 455 fWFICe /? Summary of the Invention The invention now aims at detecting in time any clogging of the nozzles. For solving this task, the invention essentially consists in that the space located of each upstream / nozzle is connected with a supply conduit a for cooling liquid via a throttle, in that each nozzle is arranged within a component part delimiting the space downstream of the throttle and iich that at least one sensor j for sensing the flow rate and/or the pressure and/or i 1J 10 the pressure difference between the supply conduit for V ... cooling liquid or the space upstream of each throttle, :x respectively, and the space located downstream of each throttle is provided for cooling liquid. On account of the space located upstream 15 the nozzle being separated from the supply conduit for cooling liquid by a throttle, the pressure difference | between the space located upstream the throttle and the | space located downstream the throttle can, in a simple manner, be utilized as an indication whether clogging of the nozzle 20 has occurred or not. Of course, the pressure within the space located downstream the throttle will, when clogging occurs, be increased relative to the pressure prevailing upstream the throttle, and when having reached a predetermined and sufficiently small pressure difference, there must be 25 concluded that the nozzle has become clogged to a great extent. In case of complete clogging of the nozzle, the pressure downstream the throttle becomes ecrual the oressure 2 1445: upstream the throttleSimultaneously, the throttle equalizes the water consumption, so that also flowmeters or pressure gauges in the supply conduit give an indication for the degree of clogging of nozzles.

The use of a throttle between the supply conduit for cooling liquid and the space located immediately upstream the nozzle, which throttle may be arranged at various locations of the supply path, allows a particularly simple arrangement being reliable in operation even in case of 10 already occurred clogging, in which arrangement at least one wall portion of the Component part carrying the nozzle, said wall portion exceeding with its surface extent the free cross section of the nozzle, is designed as a wall portion bursting prior to having reached the full pressure 15 of cooling liquid within the supply conduit. With such an arrangement, the pressure will increase downstream the throttle with beginning clogging and will reach a relatively high percentage of the supply pressure already prior to complete clogging of the nozzle. If such a bursting element 20 or, respectively, a wall portion of the component part carrying the nozzle is dimensioned such that it is blasted off or becomes cracked, the amount of liquid supplied to the cutting face will abruptly be increased at this moment, because the ejected amount of fluid ±s now determined by the 25 cross section of the throttle and no more by the nozzle. The thus immediately and significantly increased greater con-sumption of cooling liquid can immediately be used for 2 14455 signaling clogging and thus signaling cracking or blasting of a wall portion of the component part carrying the nozzle.

This arrangement has the great advantage that, in spite of an occurred clogging, supply of cooling liquid is maintained, though in an ineconomically increased degree, on account of a wall portion of the supply of cooling liquid having been cracked or burst, so that the degree of safety is reliably increased.

In a simple manner, the arrangement can be such that the throttle is arranged within an insert member sealingly inserted into the bore receiving the nozzle and connected with the component part carrying the nozzle, the mantle of said insert member having a recess for the engagement of a releasable locking member. Such an arrangement allows in a simple manner to design the component part carrying the nozzle as a cap bursting or being blast off prior to an increase of the pressure of the cooling liquid within the supply conduit up to the full pressure, noting that, as a whole, there results an insertable component part having integrated therein a throttle element and a bursting element.

Such a cap can, in a simple manner, be connected with the insertable component part in a force-locking manner for securing the nozzle in position within the bore receiving the nozzle, said insertable component part comprising a throttle bore.

As an alternative thereto, it is easily possible to arrange the throttle within a valve controlling the supply 214455 of cooling liquid, noting that such an arrangement can, for example, be realized in an advantageous manner if a construction is selected in which supply of cooling liquid is controlled in dependence on the axial bit load or axial bit shift, respectively. In all of these cases, the throttle bore shall reliably establish a definite pressure ratio between the supply peessure of the cooling liquid and the pressure upstream of the no.zzle^if the nozzle is intact or not clogged.

For making sure that supply of cooling liquid does not result in the danger of clogging the nozzles, the insertable component part and/or the supply conduit for cooling liquid is advantageously equipped with filters.

The signals of the sensors sensing pressure differences, the pressure within the supply conduit and/or the quantity of flow can be fed to a signalizing device and/or to a switching means for the drive motor of the cutting head.

Brief Description of the' Drawing In the following, the invention is further explained with reference to embodiments shown in the drawing.

In the drawing Figure .1 shows a bit holder comprising a means for supplying cooling liquid to the nozzles, said means being controlled in dependence on the bit load, Figure 2 shows a nozzle for being used in the embodiment according to Figure 1 and Figure 3 shows a modified embodiment of the device * i/ n O 2 1445 according to the invention.

Detailed Description of the Preferred Embodiments In Figure 1 ,the supply conduit for cooling liquid is schematically indicated by 1. A flowmeter 2 is inter-5 connected into the supply conduit for cooling liquid and feeds its signals to an evaluating circuit 3 and subsequently as control signals to a cutting motor 4. The cooling liquid arrives with a supply pressure of to a valve having its valve plunger designated by 5. The valve plunger 10 is shifted in the sense of the twin arrow 6 against the force of a spring 8 in dependence on the axial shift of a bit 7 and in dependence on the load of the bit, so that/ when loading.the bit,supply of liquid into the passages 9 . and thus to a nozzle 10 is given free. The nozzle 10 is 15 arranged within a nozzle body 11 which is maintained in position within a bore 13 receiving the nozzle by a safety element 12. A component part consisting of an insert member 14 and of a cap 15 is now inserted into this bore 13, this component part being shown in Figure 2. The cap 15 carries 20 the nozzle 16. The insert member 14 has a throttle bore 17. Within the space located upstream the nozzle 16 and downstream the throttle bore 17, there is continuously prevailing a pressure P2, which is, with the nozzle 16 not being /***"- clogged, lower than the supply pressure P^ for the cooling 25 liquid. The throttle bore 17 is adjusted to a pre-selected pressure ratio between the supply pressure P^ and the pressure P2 upstream the nozzle. If now the exit opening „ 7 - 2 1 445: of the nozzle becomes gradually smaller on account of adhering matter, dirt particles, lime deposits or rust particles and the quantity of flow becomes thus also smaller, the pressure P becomes greater. The pressure difference 2 between P., and P- becomes smaller. If the nozzle 16 is O 12 completely clogged, the pressure P2 becomes consequently equal the pressure P^.

The cap 15 is now designed as a bursting element and /—v designed such that it is blast off or, respectively, is cracked if P2 arrives, for example, a value of 90 percent of P^. Bursting of the cap 15 results in an increased consumption of the amount of cooling liquid, noting that if, at the latest, a certain number of caps 15 is burst, the amount of cooling liquid consumed becomes so great that a 15 distinct pressure drop of the pressure P^ can be observed in the supply conduit. In the following, the cutting motor can, as is indicated in. Figure 1, be put out of operation by means of a pressure switch. Of course and in analogy thereto, an indicator device can be actuated. 20 The component part comprising the throttle bore 17 is further equipped with sealings 18 which provide the possibility to tightly insert this component part into the bore 1.3 and to lock this component part on account of the recess. 19 r — provided in the mantle of this component part and by the locking member 12 shown in Figure. 1 .

In the embodiment according to Figure 3, the throttle bore is not provided within an insert member but immediately 2 14455 within the valve. The throttle bore is now designated by 20, and,with the valve plunger 5 assuming open'position and with the nozzle not being clogged, a pressure P2 will prevail within the bore 13 receiving the nozzle. On the 5 bottom of the bore 13, there is now provided a pressure sensor 21 having its signal conduit designated by 22. By comparing the pressure P2 measured at this location by the pressure sensor 21 with the pressure P^ measured in the supply conduit, there can be made a statement relative to 10 the degree of clogging of the nozzle, noting that the pressure difference is predetermined by the throttle 20 as long as the nozzle 10 is not clogged. In analogy to the phenomenae already described with reference to Figures 1 and 2, the pressure P2 will increase in case of increasing 15 degree of clogging, and also in this case the nozzle may be arranged within a bursting element which will burst whenever the pressure P2 within the space upstream the nozzle reaches a predetermined percentage of the pressure P^.

Filters 23 are contained within the supply conduit. 20 Furthermore, a filter 24 is connected with the component part comprising the nozzle for preventing any contamination by the cooling liquid supplied.

Claims (5)

214455 - 9 - WHAT HE CLAIM IS:

1. Device for spraying cooling liquid from nozzles of a cutting head equipped with cutting bits and rotatahlv supported on a cutting arm, in which device the cooling liauid can be supplied to the nozzles via passages within ^ the interior of the cutting head, having interposed valves actuable by the bits and/or a sector control, characterized in that the space located upstream of each nozzle is connected with a supply conduit for cooling liquid via a throttle such /"> _ . that each nozzle is arranged within a component part P. U. St f1- delimiting the space downstream^the throttle and such that at \°lim least one sensor for sensing the flowrate and/or the pressure and/or the pressure difference between the supply conduit for cooling liquid or the space upstream each throttle and the space located downstream each throttle is provided for cooling liquid.

2. Device as claimed in claim 1, characterized in that at least one wall portion of each component part, having a greater surface area than the free cross section of the respective nozzle, is designed as a wall portion and designed to burst prior to the full pressure of cooling liquid within the supply -"""N conduit being attained.

3. Device as claimed jn claim 1 or 2. characterized in that each throttle is located within an insert member sealingly inserted into a bore receiving the said nozzle and is connected w with the respective component part, the periphery of said insert member having a recess for the engagement of a 1 releasable locking member, NEV" ALAND 10 JUL 1987 | p. AT OFFICE j V • V X". *■* 214455 - 10 -

4. Device as claimed in claim 1 or 2, characterized in that each throttle is arranged within a valve controlling the supply of cooling liquid.

5. Device as claimed in claims 3 or 4, characterized in that °ach component part is designed as a cap for bursting or being blast, off prior to reaching the full pressure of cooling y liquid within the supply conduit, said cap being connected in a force-1ocking manner with an insert member which secures in P. L. B.A. position the respective nozzle within the respective bore. nevice as claimed, in any.of claims 1 to 5, characterized in * that an insert member and/or the supply conduit for cooling \° ~ /27 p.L,B.a A. linuid is equipped with filters. one porVOH 7. Device as claimed in any^of claims 1 to 6, characterized in \& f ~71 that the sensor(s) is (are) connected with a signalling device and/or with a switching means for the. drive motor of the cutting head. P. Device for spraying cooling liquid from nozzles of a cutting head substantially as hereinbefore described with reference to and as shown in Figures 1 and 2 or Figure 3 of the accompanying drawings. VOFST-ALPINE Aktiengese11schaft bv their authorised agents P.L. BFRRY & ASSOCIATES per: n vV ZEALAN 10 JUL 1987 PATENT Q^1'"" j