DE3929381A1 - Combination water meter for large and small flows - has changeover valve for Woltmann meter and auxiliary meter operated according to flow rate - Google Patents

Abstract

A Woltmann meter (1) is used as the main meter to ascertain the larger flow. An auxiliary meter (3) in a neighbouring line (2) at the side of the main meter measures the smaller flow. A change-over valve (4) behind the main meter opens upon reading a certain flow rate. The outlet (6) of the auxiliary line (2) merges into a side of the valve housing (5). The closure piece of the valve is slidable along the length axis of the valve by means of a central glide bolt. The closure force is provided by a magnetic stopper and a pretensioned pressure spring. The opening force is created by the pressure difference between the pressure of the steady water in the main meter and the low pressure arising from flow through the auxiliary meter. ADVANTAGE - By simple means, change-over valve operates automatically without outside help and without giving rise to measuring errors.

Description

The invention relates to a compound water meter with a Woltmann counter as main counter for recording the size flows, one in a branch line to the side of Main counter seated secondary counter for measuring the small flow and one behind the main counter neten, the passage through this when certain Flow opening and subsequent switching valve, according to the preamble of claim 1.

In such a compound water meter is by the Kom Combination of main and secondary counters is a much larger measurement range achieved richly than this with a single bulk water meter same nominal size is possible. The switch valve has there when the task, by exact switching the at use the calibrated individual counter for the measurement, that this from the lower to the upper measuring range limit of the compound water meter within the prescribed error tolerances.

A well-known compound water meter with a changeover control organ of this type according to German Patent 10 41 704 is characterized in that with the control body a per manent magnet is connected to a fixed space Inference part cooperates in such a way that it affects the steering wheel organ a force in the sense of the movement of the tax its final position in which it closes the main counter.

This design has the disadvantage that it is neither without bellows per, as well as with such permanently functional errors can kidney.

An encapsulation of the magnet system should preferably the compression spring and the guide bearing of the valve body two bellows bodies that are filled with a barrier fluid  protect the parts mentioned against corrosion and also smear by locking them together with the guide head forms its space, the parts lying in it, the one withdraws flow of the measuring liquid.

This has proven itself in practice but not because the Longitudinal movements of the control member as a result of what pressure of very strong bellows resistance, which rise steeply the spring tension and the required barrier fluid displacement are so braked when switching that the Fast opening necessary for a perfect changeover the valve body does not move despite the magnetic lock.

Is waived on the bellows body for the aforementioned reasons tet, then through the two bearings, in particular right through the large rear bearing, carried in the water ferritic foreign substances washed into the magnet space be and on the exposed magnet in such a way Deposit quantity that this and the parts connected with it le an unfavorable stroke shortening after a relatively short time Experienced.

This then leads to a permanent leak at the sealing seat of the control element and thus to larger measurement errors.

Furthermore, this type of construction lies in the inner chamber the piston-shaped magnet design is similar to a shock absorber, the switching movements also have a strong paralyzing effect, which is the greater, the narrower the two camp games Valve axis are executed.

Another disadvantage of training with bellows bodies is nor that the lock in the event of a defect in the bellows body liquid mixed with the drinking water.

This design is therefore hardly a practical solution for one Compound water meter switchover control device that without for years all maintenance in a pipe network should work.

The invention is based on the object of a composite water meter with a main meter, a secondary meter and  a changeover valve with a compression spring and a magnet closure with little effort and simple means to form that in the opening and closing operations of the Ver no additional measurement errors occur can.

The solution to this problem is in the features of the claim 1 seen.

The fact that in the changeover valve only a thin and within the valve stroke is always the same in diameter Sliding pin is used, results for the necessary Sliding play between the slide pin and the locking piece bore such a fine annular gap that only foreign substances from minimal size can penetrate them.

But even such foreign substances are removed in the shortest possible time Prevents further penetration into the annular gap, because the two sliding seals at the hub entrance and at the hub exit passage of the closure piece act as a through at these points let lock.

As a result of this shielding, contrary to that known th version with its thick, at the respective nominal diameter Knife of the secondary line bound control element of the valve axis, to the magnets of the magnetic lock according to the invention no foreign substances, especially no ferritic ones Foreign substances get in and settle here.

This can neither shorten the stroke nor Resistance to movement of the closure piece come to both would lead to significant measurement errors.

Another advantage of the invention is the way it works of the force determined by the respective nominal meter size to see the magnetic clasp, because this is done ne work using a so-called climbing pole effect, in which the movable in the closure piece Part of the magnetic lock due to the magnetic contact pulls along the sliding pin like a hook until the lock  piece in cooperation with the preloaded compression spring is firmly pressed against the seal on the valve seat.

This avoids any voids and it lies also no disadvantageous water displacement, as well as no shock damper-like braking effect.

Yet another advantage of the Umschaltven invention tils can be seen in the fact that the magnetic lock is spatial can be kept small, because contrary to the known version with its very large ferro magnet special high-performance magnets can be used that despite its small size, it is extremely attractive feature.

In addition, the magnetic lock is also low in terms of force kept, because the share of the compression spring in the total Clamping force is mostly predominant, while at be knew design a relatively large and strong Ma gnet and a much weaker compression spring are provided. A weak compression spring has a negative effect on Closing out because this spring that until the insertion magnetic force alone as a return device for the from Flow pressure of the water flowing through in the open position held closure piece is used, then the return process cannot perform correctly, because the pen changes a lot del- or lifting movements of the closure piece due to Fe This is prevented by vibrations caused by pressure fluctuations.

As an opening aid and to reduce pressure loss in the oven The state of the changeover valve is advantageously used also a stowage plate provided on the closure piece, which, in connection with a constriction, is an essential ent load of the spring. Has such a plate not the known version, it must therefore due to lack of discharge aids as described above with a strong magnet and a weak feather to get a sufficient Get valve relief, otherwise the pressure drop of the compound water meter too large.  

The advantage of using magnetic force as a closing aid, namely a reduction in the Fe strength and a rapid drop in holding power during the Opening process, as well as a sharp increase in the closing force during the closing process in the changeover valve, comes with the embodiment of the invention thus fully effective. It does not matter whether a spring-loaded switch valve with only one valve seat or a recently ge Common double-seat valve with the invention Magnetic lock is equipped.

This brings advantages for both valve systems because the In any case, the compression spring is never so strong in terms of force must be detected than with a valve without a magnetic closure, where the pressure loss is therefore often at the top ze of the pressure loss prescribed in the calibration regulations area.

An additional advantage, especially for the middle ones and the larger changeover valves, is also through the paired arrangement of the magnets achieved because there through increases the magnetic lock attraction strongly above the known version. With this is on Magnetic closure provided only a magnet that is not compatible with a counter magnet, but only with a magnetizable one fixed inference part cooperates and that results far less attraction.

So for the small and medium changeover valves dimensionally favorable magnetic lock is enabled Ring magnets according to claim 2 advantageous because for this is only necessary when space is limited.

Magnets in rod or block form after the on Say 3 are commercially available and therefore extremely inexpensive. This lowers the magnetic lock manufacturing cost held.  

The magnet arrangement according to claim 4 is also suitable net for smaller changeover valves that are not too big get along with closing force. Because of the bar magnet shape this version is particularly cheap in terms of manufacturing costs.

The magnetic closure according to claim 5 is for switching valves provided with extremely thin sliding pin, but nevertheless a stronger attraction for medium-sized Ven should own tiles. The double rows of magnets result the strengthening to the desired extent.

Star-shaped on the circumference of the closure piece and that of Sliding bolt distributed bar magnets according to claim 6 he give an overall strengthening of the magnetic force and are there forth preferred for medium and large changeover valves is suitable. With this magnet arrangement is also an extreme short tear-off stroke of the magnetic lock can be reached.

A magnetic closure device executed according to claim 7 bination is twice as strong as a simple magnet ver end of the same version and is therefore particularly suitable for the larger nominal sizes of changeover valves maximum closing forces.

The magnet attachment according to claim 8 shows a particular ders cheap and simple solution for a sliding pin with fixed magnetic closure part. It is suitable for all shown magnetic lock designs.

According to claim 9 injected into the closure piece Magnets do not require any other attachments, Ver Strikes in this design are therefore cost-effective cheap to manufacture.

Compact switching inserts designed according to claim 10 are very advantageous as a kit in terms of assembly, La  Maintenance and exchange, this makes installation in the Changeover valve housing is significantly simplified and Manufacturing costs significantly reduced.

The flowing arrangement of the thin according to claim 11 The sliding pin is made possible by a very short maxi Malhub of the closure piece with storage plate, so that the Sliding pin can be executed relatively short. The one-sided anchoring of the sliding pin in the switch set carrier saves a special starting camp for the rear bearing of the sliding pin and thus costs at Manufacture of the switch insert.

According to claim 12 is used instead of a special a small plate-shaped stop on the open Slide pin end as a spring abutment. This has back on the side also a support for the spring tension nut on Sliding pin end, making a simple for both devices che and cheap solution is available. The stop also serves still as a stroke limitation for the closure body in maximum Open position.

The arranged according to claim 13 in the closure piece the elastic sliding seals from a porous and what permeable material are very small and light and therefore extremely cheap to manufacture. As a result of their elasti cuddle with a slight pretension or in a bundle on the thin sliding bolt so that the Sliding clearance ring gap between the sliding pin and the ver final hub hermetically against foreign from both sides fabrics are scrimmed.

Since according to claim 14 any adjustment or regulation the switch insert assembly costs moderately affordable. The individual parts of the switch set are therefore only under tension of the compression spring  by a nut at the end of the sliding pin and by means of some Retaining screws on the outer edge of the switch insert carrier screwed to each other.

Due to the dual usability of claim 15 switching insert according to the invention there is the possibility the respective switch insert as an exchange insert in ver to use older types of federal water meter. For this, the External shape of the switch insert to the existing switch adjusted valve housing guides, z. B. by a change the switch insert carrier or by using an adapter pieces.

The conformity of the compound water meter length with the length of standard Woltmann meters vertical construction Art according to claim 16 has the advantage that instead of vertical meter with a compound water meter if required much larger measuring range built into existing lines can be changed without changing anything on the line must become. This short length also has the advantage that the manufacturing costs are far lower than for Verbundwas water meters in normal length and that they are also an essential saves weight.

Advantageously, the magnet according to the invention also lock combinations of ring magnets and Bar or block magnets possible, that depends on the space for the magnets and the necessary strength of the magnetic lock of the individual nominal diameters. Furthermore, from the same reasons the movable magnets in the closure piece be stronger and larger than the fixed magnets in the Sliding bolt.

Some embodiments of the invention are in the Drawing shown and shows  

Fig. 1 is a schematic view of a composite water meter, in short overall length from the top

Fig. 2 shows an inventive change-over valve in the closed position, in longitudinal section, with ei ner side power supply in the switch insert,

Fig. 3 is a circuit insert according to Fig. 2 in maxi painter open position,

Fig. 4 shows an inventive change-over valve in the closed position, in longitudinal section, with ei tilgehäuse ner side stream feed freely into the Ven,

Fig. 5 shows a cross section through the slide pin and the closing piece of a simple magnetic closure,

Fig. 6 shows a longitudinal section and two cross sections through a magnetic closure according to Fig. 5, however, in duplicate

Fig. 7 shows a cross section through a Magnetver circuit with radially arranged Ma gnets,

Fig. 8 is a longitudinal section through a Magnetver circuit of FIG. 7, but in combination Dual;

Fig. 9 shows a longitudinal section through a magnetic connection combination with ring magnets.

The composite water meter shown schematically in Fig. 1 consists essentially of the Woltmann meter 1 as the main meter, the seated in a secondary line 2 Ne gas meter 3 and the switching valve 4 , which are screwed together and mutually sealed.

The changeover valve 4 shown in FIG. 2 has the housing 5 with the cast-on secondary line output 6 for the secondary line 2 to be connected to it .

In the valve housing 5 sits the complete switch insert 18 , which leads with its fitting ring 24 in the housing fitting 25 ge and is sealed by means of the seal 27 against the valve interior 17 .

The switching insert 18 consists essentially of the switching insert carrier 20 , the retaining ring 26 , the longitudinally movable locking piece 7 , the fixed sliding bolt 8 , the magnetic closure 9 and the prestressed compression spring 10 .

In the slide pin 8 of the magnet is 11 or sitting the Magne te 12, which circuit the non-movable part of the Magnetver form. 9

The closure piece 7 carries in it the magnet 13 or the magnets 14 , which are the longitudinally movable part of the magnetic lock 9 . The two sliding seals 16 are arranged in the hub 15 of the closure piece 7 and the compression spring 10 is guided on the outer diameter of the hub 15 .

At the rear end 21 of the sliding bolt 8 , a plate-shaped stop 22 is provided for the compression spring 10 , which leads to the slightly offset threaded connector 28 of the sliding bolt 8 and is held by means of the spring nut 29 . A pin 30 secures the nut 29 against rotation or loosening.

With its front part 19 , the sliding pin 8 is screwed into the hub 31 of the switch insert carrier 20 and fixed by means of pin 30 .

Supporting ribs 32 connect the central hub 31 to the outer ring 33 of the switching insert carrier 20th

Pinched between the retaining ring 26 and the switching insert carrier 20 , the flexible sealing ring 34 sits with the pressure ring 35 . In the valve closing state, the sealing ring 34 is pressed firmly against the labyrinth-shaped sealing seat 37 of the switch insert carrier 20 by the circular sealing edge 35 of the closure piece 7 by the tension force of the compression spring 10 and by the attraction force of the magnetic closure 9 .

The closing piece 7 has a baffle plate 38 both when the switching movements of the closing piece 7 controls, in cooperation with the diameter slightly larger, koni rule stage 39 of the baffle ring 26 in the opening operation of the switching valve also in its closing contact. Through several channels 40 flows from the bypass line 6 via the central housing ring channel 41 de water flowing into the switch insert 18 and from here after the direction of the accumulation activity to the water not shown.

Countersunk screws 42 connect the entire switching insert 18 to form a closed assembly unit.

Flows in the valve-open position, the by Woltmann meter 1 he insert support summed water through the funnel-shaped channel 43 of the switch 20 to the diameter slightly constricted main passage 44 and from here under flow around the Ver enclosing portion 7 also to the water outlet.

The longitudinal section through the switching insert 18 according to FIG. 3 shows the position of the closure piece 7 at maximum Ven tilhub. The hub 31 of the closure piece 7 lies against the stop 22 and the magnet 13 has distant ent in the Hubbewe supply far from the fixed magnet 11 in the sliding bolt 8 , so that the magnetic closure 9 is ineffective. Both magnets 11 and 13 are also hermetically shielded from the two sliding seals 16 to the valve interior 17 in the maximum valve open position.

From the longitudinal section through the changeover valve 4 according to FIG. 4 it can be seen that the outer ring 44 with the fitting ring 24 of the switch insert carrier 20 is structurally slightly changed in this switch insert 18 , as is the outer part 45 of the retaining ring 26 .

This is necessary because the switching insert 18 must be completely closed from the outside in this embodiment, since the secondary current here is not passed into the switching insert 18 for functional reasons, but bypasses it and flows freely into the valve interior 17 at any point.

The bypass flow control required for all valve switching movements is also carried out by a separate control valve, not shown, located in the bypass line 2 with a cone and a compression spring.

Otherwise all parts of this switch insert stay but changed unverän 18, the benefits of modern magnetic closure 9 fiction, come here full effect and the prior written Meßfehlergrenzen be maintained over the entire measuring range.

In the cross section according to FIG. 5, a continuous magnet 11 in the form of a rod sits in the sliding bolt 8, and two rod magnets 14 sit in the closure piece 7 .

All three bar magnets can have the same diameter, but bar magnets 14 with a larger diameter can also be used as shown. The length of the bar magnet 11 is determined by the respective diameter of the sliding bolt 8 , the length of the two bar magnets 14, however, is arbitrary, for this the necessary attraction force of the magnetic closure 9 is decisive.

The three sections according to FIG. 6 show the same magnetic closure 9 as shown in FIG. 5, but once in a horizontal and once in a vertical arrangement. The two cross-shaped rows of magnets lie closely behind one another, only a certain stability distance is necessary for the sliding pin 8 . The two bar magnets 11 in the sliding bolt 8 and the four bar magnets 14 in the closure piece 7 provide an overall magnetic closure 9 in double strength. With regard to the magnet dimensions, the same options apply here as with the simple magnetic closure 9 according to FIG. 5.

The magnet closure 9 shown in the cross section according to FIG. 7 shows in a star-shaped arrangement six Stabma magnets 12 in the sliding bolt 8 and six bar magnets 14 in the closure piece 7 , which together provide the strength of this magnetic closure 9 .

If the diameter of the sliding pin 8 is large enough, the number of magnets in both parts 7 and 8 can also be increased as desired, and thereby also the magnetic closure strength.

Here, the outer bar magnets 14 can also be larger than the inner bar magnets 12 , whereby the magnetic closure strength is further increased.

The combined magnetic fastener according to FIG. 8 consists of two magnetic fasteners 9 as shown in FIG. 7. The distance between the two is determined by the maximum stroke of the closure piece 7 , to which a measure of safety is added, so that the outer magnets 14 of the front magnetic closure 9 are never rich in the Anzugbe the rear seated in the fixed sliding bolt 8 magnets 12 of the second magnetic closure 9 can guess. Even with this magnetic lock combination, the outer bar magnets 14 may be larger and thus stronger than those in other bar magnets 12 . This combination also provides at least a doubling of the attraction compared to a simple magnetic lock.

Also, Fig. 9 shows a magnetic closure combination be standing of two magnetic closures 9.

However, because of the lack of space and for reasons of simplification, ring magnets 11 and 13 are provided, with respect to the spacing of the two magnetic closures 9 from one another the same conditions apply as for the magnetic closure combination according to FIG. 8. The two outer ring magnets 13 in the closure piece 7 can also be larger here and thus be stronger than the two inner ring magnets 11 in the fixed sliding bolt 8 , the decisive factor is always the required attraction of the magnetic closure 9 .

The switching valve 4 according to FIG. 2 is opened as follows:

Closed Switch insert 18 and thus is stationary measuring vane of the Woltmann meter 1 as a main counter, to be detected water flows over the Woltmann meter 1, the prede ren part of the branch line 2, the sub-counter 3, the through direct part of the branch line 2, the output of the auxiliary duct 6, the housing ring channel 41 , the channels 40 , the conical congestion stage 39 and the valve interior 17 , to the not shown Darge; the amount of water is not too big.

When flowing through the secondary line 2 , as well as the Nebenzäh lers 3 , a pressure drop of about 0.2 to 0.4 bar arises, so that in the valve interior 17 a pressure lower than this prevails than in the Woltmann counter 1 .

This occurring differential pressure is usually used as an opening force for the switch insert 18 , in this case the front side of the sealing piece 7 sealed at the main passage 44 is applied.

At a predetermined flow, the switching insert 18 then automatically opens due to the differential pressure effect on the closure piece 7 against the resistance of the prestressed compression spring 10 and against the closing force of the magnetic connection 9 and the water then flows predominantly through the Woltmann counter 1 , the switching insert 18 and the Valve interior 17 to the tapping point; a small amount of water continues to flow through the secondary meter 3 . When opening, the conical barrage 39 serves as a collecting point for the closure piece 7 with its storage plate 38th This glides during its downstream opening movement contactlessly through the circular and conical step 39 and can then no longer slide back into its starting position due to the dynamic pressure occurring behind it, especially since the magnetic closure 9 has been overridden and the closing force is thereby greatly reduced. In this position, stage 39 acts like a hydraulic catch. Intermediate positions of the closure piece 7 between the main passage 44 and the stage 39 are not possible because the initial movement of the closure piece 7 remains sealed over a certain distance by the flexible seal 34 . Switching measurement errors are thus not possible during the opening process due to the fast movement of the closing piece. The flow continues to rise, then the closing piece 7 is pushed downstream by passing through the water against the resistance of the closing spring 10 on the slide pin 8, until it its maximum stroke-end position has been reached and the Ver schlußstücknabe 15 on the stop plate 22 abuts.

The switching valve 4 is closed and thus the Woltmann counter 1 is switched off in the reverse order. When there is a decrease in flow, the closure piece 7 slides upstream through the closing force of the spring 10 from its end position until it reaches the dam 39 again. Here the plate 38 again takes its jam position until the force of the closing spring 10 can overcome the jam resistance of the hydraulic catch. The closure piece 7 then slides back into its closed position without delay, especially since the magnetic closure 9 engages in the closing process again on the closing path, as a result of which the closing acceleration is considerably increased.

The main flow is thus suddenly stopped and the amount of water still flowing is recorded by the secondary meter 3 alone until no more water is drawn and both meters 1 and 3 stand still.

The opening process of the changeover valve 4 according to FIG. 4 differs somewhat from the opening process described above, because here the water coming from the secondary meter 3 is not passed through the annular channel 41 into the switching insert 18 , but directly into the valve interior 17 of the housing 5 and from because flows out to the water tapping point.

In the opening phase, the sidestream is therefore throttled by a control valve arranged behind the secondary meter 3 in the secondary line 2 at a predetermined flow so strongly that the predominant amount of water then flows through the Woltmann meter 1 and acts on the closure piece 7 from here.

The decisive factor here is that the magnetic closure 9 is still overridden during the initial travel of the closure piece 7, which is sealed by the flexible sealing ring 34 , and this thereby receives an abrupt thrust in the direction of the valve output.

As a result of this operation, the baffle plate 38 slides through the conical non-contact as derum weir 39 and out ter this the already mentioned locking or storage position, a ter is pushed to the stopper 7 by increased flows downstream white increases.

Also with this valve, the maximum stroke of the closure piece 7 ends at the plate-like stop 22 at the rear end 21 of the sliding pin 8 .

This changeover valve 4 is also closed from the conical weir 39 . After the baffle plate 38 plunges into it, it slides through and after a short closing stroke then the magnetic lock 9 comes into force again, the closure piece 7 is thereby accelerated in its closing movement so that it is suddenly pushed onto the sealing ring 34 on the main passage 44 and this closes.

The water flowing up to this situation through the Woltmann meter 1 is then fed to the secondary meter 3 and thereby inevitably expands the spring-dependent flow cross section in the control valve in the secondary line 2, which was almost closed by then.

The flows through the Woltmann meter 1 and the Nebenzäh ler 3 are thus automatically switched on and off by certain differential pressures in the changeover valve 4 and in the control valve (not shown) so that measurement errors due to incorrect or not detectable amounts of water are not possible.

Both switch valves 4 are also designed so that they also have a water reflux, for. B. break in a pipe in front of the compound water meter is prevented. For the Woltmann counter 1 , the elastic sealing ring 34 is used in conjunction with the labyrinth-shaped sealing seat 37 of the switching insert carrier 20 and with the circular sealing edge of the closure piece 7 as a non-return valve.

By the secondary meter 3 , a reflux is prevented by the fact that in the compound water meter with a changeover valve 4 according to the first version in the secondary line 2 a special check valve sits and in the compound water meter with a changeover valve 4 after the second version the control valve already present still serves as a backstop.

Claims (16)

1.Compound water meter with a Woltmann meter ( 1 ) as the main meter for recording the larger flows, a secondary meter ( 3 ) located in a secondary line ( 2 ) to the side of the main meter for measuring the smaller flows and a passage arranged behind the main meter to pass through it certain upon reaching flows opening and closing valve (4), in the housing (5) of the output (6) opens the secondary line (2) side and the closure member (7) is displaceably guided in the valve longitudinal axis by means of a central slide pin (8) , The switching valve closing force is formed by a magnetic closure ( 9 ) and a pre-tensioned compression spring ( 10 ) and the Umschaltven valve opening force by the pressure difference acting on the closure piece ( 7 ) in the valve opening direction between the pressure of the standing water in the main meter and that while the secondary meter is running ( 3 ) in Valve housing ( 5 ) due to flow pressure loss of the secondary meter ( 3 ) entering low pressure, characterized in that the non-movable part of the magnetic closure ( 9 ) consists of one or more ren permanent magnets ( 11, 12 ) which are in or on a spatially fixed, Made of a non-magnetizable material, thin slide bolts ( 8 ) of the changeover valve ( 4 ) are seated, and the longitudinally movable part of the magnetic closure ( 9 ) consists of one or more permanent magnets ( 13 ) chambered inside the closure piece ( 7 ), which is partially or completely made of a non-magnetizable material , 14 ) is formed, the magnet ( 11 ) or the magnets ( 12 ) of the sliding bolt ( 8 ) and the magnet ( 13 ) or the magnets ( 14 ) of the closure piece ( 7 ) being spatially arranged such that they are in the valve-closing state with respect to one another are in maximum contact and all magnets ( 11, 12, 13, 14 ) from the locking piece hub ( 15 ) with two elas table sliding seals ( 16 ) and are constantly shielded from the sliding bolt ( 8 ) in the valve stroke area ( 8 ) with respect to the valve interior ( 17 ) in the valve closing state and during the entire valve stroke. 2. Compound water meter according to claim 1, characterized in that the magnet ( 11 ) in the sliding bolt ( 8 ) and the magnet ( 13 ) in the closure piece ( 7 ) are designed as ring magnets. 3. Compound water meter according to claim 1, characterized in that the magnets ( 12 ) in the sliding bolt ( 8 ) and the magnet ( 14 ) in the closure piece ( 7 ) are designed as bar or block magnets. 4. Compound water meter according to claims 1 and 3, characterized in that the magnetic closure ( 9 ) is formed in the simplest way by a bar magnet ( 11 ) in the sliding bolt ( 8 ) and by two bar magnets ( 14 ) in the closure piece ( 7 ). 5. Compound water meter according to claim 4, characterized in that the entire magnetic closure ( 9 ) consists of two short rows, cruciform arranged rows of magnets, two bar magnets ( 11 ) in the slide bolt ( 8 ) and four bar magnets ( 14 ) in the closure piece ( 7 ) ) be used. 6. Compound water meter according to one or more of claims 1 to 5, characterized in that the magnets ( 12 ) in the sliding bolt ( 8 ) and the magnets ( 14 ) in the closure piece ( 7 ) are arranged in a star shape. 7. composite water meter according to claim 6, characterized in that the magnetic closure ( 9 ) as a magnetic closure combination is carried out twice, the distance between the two magnetic closures is somewhat larger than the maximum stroke of the closure piece ( 7 ). 8. Compound water meter according to claim 1 and further, characterized in that the magnets ( 11, 12 ) in the sliding bolt ( 8 ) are sintered. 9. Compound water meter according to claim 1 and others, characterized in that the closure piece ( 7 ) is advantageously injected from a non-magnetizable plastic and the magnets ( 13, 14 ) are injected into the closure piece ( 7 ). 10. Compound water meter according to one or more of claims 1 to 9, characterized in that the switching valve ( 4 ) has a replaceable switching insert ( 18 ) which is designed as a self-contained assembly. 11. Compound water meter according to one or more of the claims 1 to 10, characterized in that the sliding bolt ( 8 ) with its front part ( 19 ) is firmly anchored in the switch insert carrier ( 20 ) of the switch insert ( 18 ). 12. Compound water meter according to one or more of claims 1 to 11, characterized in that the sliding pin ( 8 ) has a stop ( 22 ) for the compression spring ( 10 ) at its free end ( 21 ). 13. Compound water meter according to one or more of che Ansprü 1 to 12, characterized in that the piece in the closure ( 7 ) arranged elastic sliding seals ( 16 ) made of a water-permeable, porous material, for. B. are made of felt or foam. 14. Compound water meter according to one or more of the claims 1 to 13, characterized in that for the switching insert ( 18 ) only simple assembly is required, without any adjustment or regulation activity. 15. Compound water meter according to one or more of claims 1 to 14, characterized in that the magnetic closure according to the invention ( 9 ) is suitable both for a composite water meter version in which the water flowing through the secondary meter ( 3 ) flows directly into the through a special supply line switching insert (18) is passed is suitable, as well as flows of a composite water meter type in which funktionsge Mäss the secondary meter water bypassing the Schalteinsat zes (18) free of Umschaltventilge häuses into the interior (17) (5). 16. Compound water meter according to claims 1 and others, characterized in that the respective Verbundwasserzäh ler overall length for all nominal sizes, preferably with the construction length of standardized Woltmann meters of vertical design agrees.