DE29701378U1 - Device for penetrating a batch of metallic workpieces - Google Patents

Description

Stenger, Watzke & Ring.·.". .: : : ^^«Friedrich-Ring 70

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PATENT ATTORNEYS

Our reference: 97 0015

Ipsen International GmbH Flutstrasse 78
47533 Cleves

DIPL.-ING. WOLFRAM WATZKE

DIPL.-ING. HEINZ J. RING

DIPL.-ING. ULRICH CHRISTOPHERSEN

DIPL.-ING. MICHAEL RAUSCH

DIPL.-ING. WOLFGANG BRINGMANN

Patent attorneys

european patent attorneys

17 Jan 1997

Device for penetrating a batch of metallic workpieces

The invention relates to a device for penetrating a batch of metallic workpieces with a moving, fluid medium, for example as part of a heat treatment for preferably quenching a batch of metallic workpieces in a moving, fluid quenching medium. The term heat treatment of metallic workpieces also includes any cleaning processes that may be required, which can be carried out as individual processes alone or in combination with quenching processes in order to wash batches or to remove quenching medium adhering to the workpieces.

When quenching hardened material, e.g. in water, oil or salt baths, it is known that the properties of the cooled workpieces, such as surface hardness, brittleness, etc., depend on the one hand on the temperature difference between the workpiece surface and the quenching medium, and on the other hand on the quenching or cooling speed and the medium used for quenching. With a given quenching medium, the cooling speed can be influenced both by the selected initial temperature of the quenching bath and by additional heat-exchanging relative movements between the batch and the quenching bath. For this purpose, it is known in the prior art to move the quenching medium through one or more circulation devices, pumps or similar in order to influence the workpiece properties via the cooling speed that can be changed as a result.

In order to ensure good heat transfer from the workpieces to the quenching medium and to avoid local overheating of the quenching medium, it is also known that batches of metallic workpieces immersed in the quenching medium are flowed around or through in a defined manner by the quenching medium, if necessary with the additional use of guide devices, and the absorbed heat is dissipated by means of suitable cooling devices.

Since the local flow conditions on the workpieces in particular influence the intensity of the heat transfer, additional measures are known that increase the intensity of the flow or change its direction in order to influence the local heat transfer conditions in the sense of a low-distortion and uniform hardening of the quenched material. In addition to reversing the direction of the flow using circulation devices, these measures also include the use of one or more nozzles through which the charge can be flown at high speed. The disadvantage of the known measures is that the desired improvement in the local heat transfer conditions can only be achieved with considerable effort, for example by using entire nozzle fields or by designing the circulation devices in such a way that they also allow circulation in the opposite direction. The latter also carries the risk that the inertia of the fluid when the direction is reversed can lead to unacceptably long downtimes. The effect of the jets also decreases with increasing distance from the nozzle orifice due to the inertia of the surrounding medium, so that in the case of complex batches only the outer surfaces of the batch are reached and the flow to workpieces further inside is no longer possible.

In the prior art, devices of the generic type are also known in which a movement of the charge in a vertical and/or horizontal direction is possible in order to bring about alternating flow movements in the quenching tank. However, this has the disadvantage that in addition to only one immersion device, which is usually present, vertical and/or horizontal movement and guidance devices for the charge are also required, which usually correspond to a

are subject to high financial and construction costs. In addition, there is a risk that when the batch is moved, partial surfaces of complicated workpieces within the batch will continue to be disadvantaged by the flow.

Furthermore, an additional horizontal movement of the immersed charge in an already existing vertical flow, for example as a result of circulation devices with vertical guide devices, has the consequence that, depending on the different charge positions, either an enlarged flow area must be present within the quenching tank or the flow device must be moved along, which involves considerable effort.

With regard to the application of the device mentioned above to washing/cleaning processes, it is known to immerse the batch in a container with a cleaning liquid and to move the cleaning liquid in a similar way to the quenching medium during quenching. The cleaning result is often inadequate if the parts to be cleaned have a complicated geometry, have cavities (blind holes) or are located in the flow shadow of other parts in batches made up of several parts.

Based on this, the invention is based on the object of specifying a device for penetrating batches of metallic workpieces, in which the disadvantages described are eliminated and, in particular, an effective flow through batches of metallic workpieces, the intensity of which can be easily varied, is achieved.

To achieve the object, the invention proposes a device consisting of a quenching tank containing a fluid bath and a device for introducing the charge to be quenched, wherein at least one displacer that can be moved back and forth by a drive is arranged in the quenching tank to generate a bath movement that flows around and through the charge in a defined manner, by means of which specific flow directions can be imposed on the fluid quenching medium.

The displacer expediently has a cross-sectional profile that is half-open in the axial direction and encloses a submerged charge on three sides in a movable manner, so that a concentrated, if necessary large-volume flow through the charge can be achieved due to the geometric shape. For the same purpose, it is proposed that the displacer alternatively has a cross-sectional profile that is closed in the axial direction and encloses a submerged charge on four sides in a movable manner.

In order to meet the usual dimensions of a batch on the one hand and to achieve the largest possible displacement volume on the other hand, the cross-sectional profile is preferably essentially U-shaped or alternatively rectangular. It is also proposed that the axial side walls of the displacer, which is U-shaped in cross section or alternatively rectangular, are parallel to the lateral batch surfaces in the direction of movement and also surround them closely but without contact over their entire extent at all times, so that the fluid moving in the direction of movement of the displacer flows almost exclusively through or around the batch.

The invention is further advantageously characterized in that the end wall of the U-shaped displacer perpendicular to the direction of movement has a variable distance from the corresponding charge surface opposite it, or that the end walls of the alternative rectangular cross-section displacer perpendicular to the direction of movement have a variable distance from the corresponding charge surfaces, which in each case allows unhindered movement of the displacer without touching the charge, so that a variable displacement volume of the displacer is possible in accordance with the distance of the end wall(s) from the corresponding charge surfaces.

It is expedient to vary the displacement speed depending on the intensity of the bath movements required for quenching, so that, for example, an optimal cooling speed can be achieved for different batches with workpieces of varying complexity. For the same purpose, it is also proposed that the displacement movements be varied depending on the intensity of the bath movements required for quenching.

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Flow behavior of the bath movement is either continuous or with interruptions, periodically alternating or even pulsating at high frequencies with large or small stroke volumes.

Preferably, the direction of movement of the displacer is horizontal in order to achieve a horizontal flow around or through the charge to be quenched.

In an advantageous embodiment of the invention, the displacer is arranged in the quenching tank so as to be freely suspended or alternatively guided by rollers/rails in order to ensure simple but nevertheless safe guidance of the displacer.

Finally, it is proposed that hydraulic/pneumatic cylinders or alternatively pull rods or rotating chains are used to drive the displacer, so that a travel movement that corresponds to the respective requirements is ensured.

Further details, features and advantages of the subject matter of the invention are explained in more detail below using two preferred embodiments shown in the drawing. In them:

Fig. 1 is a schematic representation of the displacer during suction stroke in

a top view;

Fig. 2 is a schematic representation of the displacer during pressure stroke in

a top view;

Fig. 3 is a schematic side view of the displacer and

Fig. 4 is a schematic representation of an alternative embodiment

of the displacer in a top view.

In the device for quenching a batch 3 of metallic workpieces according to the method according to the invention shown schematically in Figs. 1 and 2, the structure and the mode of operation of the

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The object of the invention can be seen during the suction or pressure stroke. The device shown comprises a quenching tank 1, which is filled with a fluid quenching medium 2 and into which the charge 3 is inserted after a previous heat treatment by means of an introduction device (not shown). Possible fluid quenching media include, for example, water, water with dissolved salts, water with polymers, various oil qualities and salt baths. A displacer 5 guided on rails 4 in the horizontal direction of movement comprises a hydraulically or pneumatically driven cylinder 6, to which a displacer profile 7 with a U-shaped cross-section in the axial direction is connected, which encloses the immersed charge 3 on three sides.

The axial, limb side walls 8 of the U-shaped cross-sectional profile 7 are arranged in such a way that they are parallel to the lateral outer surfaces 9 of the charge 3 in the direction of movement of the displacer 5 and also surround them over their entire extent at all times, close to but without contact, which can be clearly seen in particular in Fig. 3. The distance 10 between the outer surfaces 9 of the charge 3 and the side walls 8 of the displacer 5 is dimensioned in such a way that it is as small as possible, but still allows a lateral flow around the outer surfaces 9 of the charge 3 and a contact-free movement of the displacer 5.

Between the front wall 11 of the displacer 5, which is arranged perpendicular to the direction of movement, and the charge surface 12 opposite it, there is a distance 13 which is variable according to the displacer movement and which allows an unhindered movement of the displacer 5 towards or away from the charge 3 without touching it, as can also be clearly seen from the alternative embodiment of the displacer 5 in the form of a rectangular cross-sectional profile 17 shown in Fig. 4.

If the displacer 5 moves in the manner shown in Fig. 1, the quenching medium 2 is sucked into the cavity 14 that forms behind the front wall 11. The charge 3 is thereby flowed around or through in the direction of the displacer movement (suction stroke). If the direction of movement is reversed, which can be seen in Fig. 2, a reversal also takes place.

or flow through the charge 3, in which the fluid quenching medium 2 now located in the cavity 14 is pushed away in the direction of movement (pressure stroke).

The flow profile of the fluid quenching medium 2 is characterized during the displacement movement by the fact that an almost laminar flow is formed in the interior space spanned by the displacement geometry, which, after exiting the charge 3, hits the wall of the quenching tank 1, is thus diverted and flows back in the opposite direction on the outside of the displacer 5. Since in the embodiment there are no floor or cover walls delimiting the displacer 5 at the top or bottom, a flow in the vertical direction also takes place with each displacement movement, in that the fluid quenching medium 2 flows into the cavity 14 formed by the displacement movement from above or below. This vertical turbulence causes circulation and mixing of the entire quenching tank 1, so that almost the entire bath volume is used for heat exchange. The additional use of circulation pumps to dissipate the absorbed heat via suitable cooling devices can therefore be partially or completely dispensed with.

In the alternative embodiment according to Fig. 4 in the form of a rectangular cross-sectional profile 17, the quenching medium 2 is moved through the charge 3 from one end wall 11 of the displacer 5 to the opposite one. Due to the cross-sectional profile of the displacer 5 being closed in the axial direction, two opposing flow movements are formed inside and outside the displacer 5 during the displacement movement, which, however, are in mutual exchange via a vertical fluid movement flowing through the top and bottom open surfaces of the displacer 5 into the respective cavities 14, so that very strong heat-exchanging turbulences spread outside the charge 3.

Depending on the intensity of the heat transfer between charge 3 and quenching medium 2 required for quenching, the

The travel speed of the displacer 5 and thus the flow movement imposed on the fluid 2 as well as the fluid volume vary. Due to the control by means of hydraulic/pneumatic cylinders, both continuous, periodically alternating or high-frequency pulsating travel movements and non-linear, interrupted movements with large or small strokes are possible.

Alternatively, the displacer 5 can also be guided on rollers 15 or have, for example, a rotating chain 16 as a drive, as can be seen in Fig. 3.

The device for quenching metallic charges 3 shown in the embodiments can be used both directly to generate a flow movement in the quenching tank and to divert or focus a flow around and through the charge 3 that has already been generated by other means, for example by additionally using circulation devices, in a cost-effective manner and is therefore characterized by a particularly wide range of applications compared to the devices known in the prior art.

List of reference symbols

1 pool

2 fluid medium

3 batches

4 rails

5 Displacers

6 hydraulic pneumatic cylinders

7 U-shaped cross-sectional profile

8 side walls

9 lateral outer charge surfaces

10 lateral distance

11 Front wall

12 frontal outer surface of the charge 1 3 frontal distance

14 Cavity

15 rolls

16 rotating chains

17 rectangular cross-section profile

Claims (14)

• · Claims 1. Device for penetrating a batch of metallic workpieces in a moving, fluid medium, consisting of a tank (1) containing a fluid bath, preferably a quenching tank, and a device for introducing the batch to be quenched (3), characterized, that in order to generate a bath movement flowing around and through the charge (3) in a defined manner, at least one displacer (5) which can be moved back and forth by a drive is arranged in the basin (1), by means of which specific flow directions can be imposed on the fluid medium (2), preferably quenching medium. 2. Device according to claim 1, characterized in that the displacer (5) has a cross-sectional profile that is half-open in the axial direction and that encloses an immersed charge (3) on three sides in a movable manner. 3. Device according to claim 1, characterized in that the displacer (5) alternatively has a cross-sectional profile which is closed in the axial direction and which encloses an immersed charge (3) on four sides in a movable manner. 4. Device according to claim 2, characterized in that the cross-sectional profile is substantially U-shaped. 5. Device according to claim 3, characterized in that the cross-sectional profile is rectangular. 6. Device according to claim 4, characterized in that the axial side walls (8) of the displacer (5) which is U-shaped in cross section are parallel to the lateral charge surfaces (9) in the direction of movement and also surround them closely but without contact over their entire extent at all times. 7. Device according to claim 5, characterized in that the axial side walls (8) of the displacer (5) with a rectangular cross-section are parallel to the lateral charge surfaces (9) in the direction of movement and also surround them closely but without contact over their entire extent at all times. 8. Device according to claim 6, characterized in that the end wall (11) of the cross-sectionally U-shaped displacer (5) perpendicular to the direction of movement has a variable distance (13) from the charge surface (12) opposite it, which allows unhindered movement of the displacer (5) without touching the charge (3). 9. Device according to claim 7, characterized in that the end walls (11) of the displacer (5) which are perpendicular to the direction of movement have a variable distance (13) from the corresponding charge surfaces (12), which allows unhindered movement of the displacer (5) without touching the charge (3). 10. Device according to one of the preceding claims, characterized in that the travel speed of the displacer (5) can be varied depending on the intensity of the bath movement required for quenching. 11. Device according to one of the preceding claims, characterized in that, depending on the flow behavior of the bath movement required for quenching, the displacement movements of the displacer (5) are either continuous or intermittent, periodically alternating or even pulsating at high frequencies with large or small stroke volumes. 12. Device according to one of the preceding claims, characterized in that the direction of movement of the displacer (5) is horizontal. 13. Device according to one of the preceding claims, characterized in that the displacer (5) is arranged in the tank (1), preferably a quenching tank, so as to be freely suspended or alternatively guided by rollers/rails (4/15). 14. Device according to one of the preceding claims, characterized in that hydraulic/pneumatic cylinders (6) or alternatively pull rods or rotating chains (16) are used to drive the displacer (5). R/SC/ri