DE10065428A1 - Hydraulic seat valve contains conical, parabolic or hemispherical piston arranged so that its cross-section decreases towards closing position, piston moving in guides which keep it in straight line and being biased towards closed position - Google Patents

Abstract

The hydraulic seat valve contains a conical, parabolic or hemispherical piston (2) arranged so that its cross-section decreases towards the closing position. The piston moves in guides (18) which keep it in a straight line and is biased towards the closed position by a spring (22). The pressure of the hydraulic fluid on the cross-section of the guides also acts towards the closed direction. The piston is made from a material which is softer than that of the valve seat, or vice-versa.

Description

The invention relates to a seat valve according to the preamble of claim 1.

Such a seat valve and its problems are such. B. known by the DE-A 199 17 651.5 and the patent applications resulting therefrom.

Basically, a valve seat of a seat valve is formed in that an esp special frustoconical piston collar of the closing piston on a geometrically identical, but complementary shaped inner cone of the stationary Seat body rests under a closing load and thereby the flow through blocked the central passage of the seat body. Such a valve seat is z. B. used as a pressure relief valve, safety valve or check valve; in this The secured hydraulic pressure acts against the closing direction and against the closing force and leads to the opening of the closing piston when the hydraulic Pressure overcomes the closing force. In this case, the closing force z. B. by a Spring exercised, the biasing force according to the desired security radio tion is adjustable.

With the reverse function of such a seat valve, the closing force applied by the secured hydraulic pressure and the closing piston is opened by other forces.

The problem with old these seat valves is that it is very difficult to hydraulics to secure systems with high pressures, especially pressures above 50 bar. Here small openings and gaps, such as those created by the control itself, but also due to contamination or tolerances of the seat surfaces, in Se Customer-friendly to the excavation of the seat surfaces, which make the seat valve unusable and pose a significant security risk. This problem persists especially in mining applications where it happens very suddenly and unexpectedly very high pressures in the expansion controls and expansion plates can come when unforeseen mountain movements occur.

The object of the invention is to design a seat valve so that it is sudden Pressure increase opens very quickly and wide and very much when the pressure drops closes quickly; furthermore, unwanted tolerances, inaccuracies or uncertainties inclinations of the seat surfaces do not lead to the destruction of the valve and it should  prevent contamination of the hydraulic oil or hydraulic fluids fix liquids in the area of the seats.

The solution results from claim 1

By loading the cross-sectional area of the straight guide with the hydraulic The inlet pressure of the inlet side in the closing direction is very fast Closing movement and such a high closing pressure that tolerances of the seat fits be balanced.

The embodiment of claim 2, wherein the seat body in the area of the seat consists of a material that is much softer than the material of each other closing body in the area of the seat has the advantage that a Compensation results even at lower closing pressures.

The combination according to claim 3 offers a safe solution in which also stray inclinations or rough tolerances do not lead to the valve failures described can.

The invention also includes further developments of the measures to increase the Closing pressure (claims 4 and 5) and the measures to adjust the seat tube satchel (claims 7 to 18). These training courses are also applicable to the station wagon nation applicable according to claim 3.

Claims 4 and 5

In the embodiment according to claim 4, wherein the straight guide of the movable Closing piston is on the inlet side, there is a very short design of the Piston. Since the hollow cylinder is flowed through from the inlet side, they act considerable flow forces on the piston, which for quick closing of the Guide valve seat in case of pressure drop. Even a small opening of the valve leads to a very sudden increase in pressure in the pressure space surrounding the valve seat and thereby additional opening forces on the piston.

In the embodiment according to claim 5, the sealing surface of the shaft, which the Outlet side of the valve opposite the spring chamber connected to the inlet side sealing separates, pressure-compensated on both sides, so that only the slight when closed much larger ring area on the inlet side is loaded with the inlet pressure and increases abruptly when the piston is lifted slightly.

Regarding claims 6 to 18, it is pointed out that the better view preferably because of it in the following description of the invention it is assumed that the seat with the softer material in the fixed Seat body is formed. (Claim 18). However, the invention is not based on this  limits There may well be applications in which it is expedient to fit the seat to produce the surface of the locking piston from a softer material.

The seat is so small in the axial direction that the soft material of the clasp deformed to a degree under the closing load, preferably elastically in deformed to a dimension which is beyond the dimension of the fit tolerances of the acting closing surfaces goes beyond this embodiment according to claim 7 is the softness of the closing body not only from the choice of material but also made dependent on the dimensioning, which is one for the material selection granted useful leeway.

It is not necessary for the entire seat of the seat body to be made of one of these soft material. Rather, it is the special advantage of training according to claim 8, that the seat made of hard material is longer in the axial direction and the seat is made of soft material.

To increase the elasticity is the embodiment of claim 8, in which the white surface material is inserted into the groove as a ring insert in a groove, that the sides of the groove bil the abutment of the ring insert against the closing force the.

It is known that the pairings of seat body and seat piston are in the loading rich in the seats must work together and that this ge happens that a partially plastic deformation of at least one of the two Closing body occurs in the area of the seat surfaces due to the closing force. It can however, it often happens that the pressure load required for the se mutual adjustment of the seats is required, the ones already mentioned Excavation and destruction of the valve occurs. It is also plastic Deformation and deformability of the closing surfaces are inevitable that further Gaps occur if and so often not the highest pressure load that has occurred up to that point tion prevails. In this fold there is again the risk of scouring through leakage oil flows.

For this reason, it is proposed that the softer material be preferred under the pressure load not plastic but only elastic or essentially lichen is only elastically deformable or that even under the highest pressure load sufficient elastic deformation is always left. This requirement fulfills above all a seat, which is formed from a plastic body. A suitable plastic is e.g. B. polyoxymethylene (POM), commercially z. B. under the Brand name Delrin.  

By appropriate dimensioning of the seats and especially that of soft Material existing seat is achieved that inevitable manufacturing and Assembly tolerance can be compensated for and that in addition generous Tolerances can be applied and manufacturing costs can be saved. About it there is the advantage that the gap between the seats in the direction of flow is very short. It is preferably not longer than 4 mm, preferably not longer than 3 mm. This reduces the risk of contamination in the gap clamp. In addition, the flow rate due to the low Gap lengths increased so that contaminants are washed out with great certainty become. From this aspect, the training according to claim 17 is particularly advantageous arrested.

The seats are naturally the surfaces of ring-shaped bodies, the cone shaped, spherical shell - shaped, paraboloid - shaped or other shape can. It is essential for this shape that these bodies have radial cut surfaces ben whose diameter decreases linearly or progressively in the closing direction. Thereby it is achieved that the closing surfaces touch flat under the closing load. The closing surface made of soft material is also the surface a ring body made of soft material. This ring body is in the other material - usually steel - of the locking piston or the seat body bedded. In the development according to claims 8 to 12, this ring insert made of soft material embedded in a groove. The advantage of this training lies in that the side flanks of the groove prevent the soft material of the rings from being can dodge sideways; in any case, the elasticity is limited depending on the dimensioning of the groove on the one hand and the ring insert on the other. This special development according to claim 12 gives the possibility of the pages flanks of the groove and thus the freedom of the ring insert to extend laterally soft, more or less limit.

When designing the groove, it is important that the side flanks and the end faces the groove the relative closing movement of the locking piston and seat body and thus do not hinder intimate contact between the seats. The training courses according to claims 10 and 11 denote solutions to this problem. In the Further development according to claim 10, the side flank consists in particular of a soft metal, e.g. B. a copper alloy, which is so far under the closing load plastically deformed so that they consist of the closing movement of soft material the closing surface and the corresponding elastic deformation of this closing surface not disabled.  

Alternatively, the ring insert is placed on a by the closing surface of the closing piston axially limiting bearing surface pressed in the axial direction and thereby the elasti cal evasive movement essentially limited to the radial direction. To at Opening the seat valve and lifting the closing piston an axial movement of the To prevent ring insert, this is preferably inserted axially on its support stuck, e.g. B. by a screw-in socket.

Preferably, the soft material insert in the axial passage and in the Seat of the closing body is formed.

In the following, exemplary embodiments of the invention are illustrated wrote.

Figs. 1, 2 and 3 show different embodiments of seat valves.

In this case, functionally identical parts are designated with the same reference symbols. In the seat valves of FIG. 1 is a so-called. Massif valve / Ge birgsdruckventil / rock burst valve. Valves of this type are used in mining to secure the hydraulic circuits of the hydraulic shields. Their function is to be able to drain very large quantities of oil in the event of suddenly higher pressures and to close them again very quickly after the pressure has been reduced. The seat valve 1 has a closing piston 2 . The locking piston is guided with a shaft 17 in a guide body 18 . The guide body 18 is sealed in a Pa trone 19 sealing (seals 20 ) and forms the spring space 21 in the cartridge 19 . The shaft 17 of the closing piston 2 is pressed in the closing direction 10 by spring 22 . The locking piston with shaft 17 is pierced with an axial channel 23 . The axial channel 23 connects the spring chamber 21 to the inlet or pressure chamber 24 to be secured. The closing piston 2 has on its side facing away from the spring chamber 21 a conical closing surface 4 , which is formed as a jacket of a truncated cone. The closing surface 4 of the closing piston forms, together with the closing surface 5 of the stationary seat body 3, which is also in the form of a truncated cone, the valve seat. As a result, the closing piston 2 closes the pressure chamber 24 with respect to the tank connection 25 and outlet chamber 26 under the spring force 22 acting in the closing direction 10 . The shaft 17 of the locking piston 2 is sealed against the Füh approximately body 18 by seal 27 . This means that the inlet 24 is connected to the spring chamber 21 via the central channel 23 in the closed position. Since it should be mentioned that the hydraulically effective cross-sectional area of the shaft 17 in the region of the seal 27 is smaller than the hydraulically effective annular surface which is formed on the closing surfaces 4 , 5 and the closing piston and closing body when the closing piston 2 is closed. It therefore acts the hydraulic pressure in the inlet 24 partially in the opening direction against arrow 10 , so that the closure of the closing piston 2 is caused by the spring 21 .

As soon as the pressure in the inlet 24 overcomes the spring force, the oil penetrates into the gap between the seat surfaces 4 and 5 . This increases the hydraulically effective piston area on the closing piston 2 in the opening direction, so that the closing piston opens very quickly and, due to the aerodynamic shape, in particular due to the short length, allows the large amount of oil required for the reduction of the excess pressure to pass into the outlet space 26 .

The closing surfaces 4 and 5 are made very short in the axial direction, so that a gap of short length is created when the closing piston 2 is opened. As a result, the pressure drop based on the gap length is very low and a high flow rate is achieved. Therefore, oil contaminants have no chance of settling.

The stationary seat body 3 is designed as a ring made of soft material. This ring insert has - as already stated - a conical seat surface, which interacts with the accordingly shaped seat surface of the closing piston 2 and which forms the passage between the pressure chamber 24 and the lassraum from the valve 26 when the closing piston is open. The seat body 3 lies on an annular shoulder 28 of the hollow cylindrical valve housing 29 . It should be mentioned that the valve housing 29 is made in one piece with the guide body 18 . In the free end of the hollow cylindrical valve housing 29 , an annular cylindrical bush 11 is screwed, the central passage 30 with the central channel 23 , which penetrate the locking piston 2 and its shaft 17 , are in alignment. The annular end face of the socket 11 forms, together with the facing annular surface of the shoulder 28, the side flanks - here designated 9 - a groove 7 . The cross-sectional area of this groove 7 essentially corresponds to the cross-sectional area of the seat body, ie the ring insert 3 . This seat body 3 protrudes from the free annular opening of the groove with a small area at which its closing surface 5 is formed. This means that the closing surface 4 of the locking piston 2 in the closed position and under the action of the spring force 22 has no contact with one of the end faces 8 of the groove. For this purpose, the end faces can be made so that they come back behind the outer circumference of the locking piston and behind the closing surface 5 of the seat body 3 . Alternatively, the bushing 11 can be made of a soft material which is plastically deformed by the action of the spring 22 such that with a lower spring force or with partial compensation of the spring force by the pressure in the inlet 24 there is no longer any contact with this end face 8 . The stationary seat body 3 is sealed at the base of the groove with respect to the valve housing by a seal 31 .

With regard to the material selection for the seat body 3 , a high surface pressure is intended. The axial length of the closing surface 5 is therefore very small. This is to occur in the closed state and under the spring force 22 such an elastic deformation that all tolerances between the closing surfaces are leveled and compensated for contaminants that are not crushed, nest in the material of the closing surface.

The valve according to FIG. 2 also fulfills the function of securing an inlet 24 by connection to an outlet space 26 and a tank connection 25 . The valve housing 2 g is a hollow cylinder which on the one hand has the inlet 24 and on the other hand the tank connection 25 In the valve housing 29 a radial shoulder 32 is formed on which the support ring 33 rests. The support ring 33 forms a groove 7 on the one hand with an annular projection 34 and on the other hand with the cylindrical side wall of the valve housing 29 . The stationary seat body 3 is inserted into this groove 7 . The seat body 3 is designed as an annular disc that fits into the groove 7 . The seat body 3 protrudes beyond the groove in the axial and radial directions and thereby protrudes beyond the annular projection 34 of the support body 33 . The seat body 3 thereby forms an overlying circumferential surface, which forms the frustoconical closing surface 5 and wel che cooperates sealingly with the correspondingly shaped closing surface 4 of the locking piston 2 .

The closing piston 2 is a hollow cylinder, the end face of which is closed on its closing side or can possibly contain a nozzle bore. The piston 2 is not sealingly guided in the outlet space 26 , which also serves to receive the closing spring 22 .

The hollow cylinder has a large hydraulic collar in the area of the valve seat Cross-section that compared to the rest of the valve housing and the interior of the Piston forms a separate pressure chamber. When opening the valve seat the oil first in this pressure chamber before it through radial openings of the Hohlzy linders can flow into the interior and the tank. The bigger the dissipate en is the amount of oil, the greater the pressure increase in the pressure chamber, which leads to the opening of the valve also contributes a small opening of the valve leads to a very sudden Chen pressure increase in the pressure chamber surrounding the valve seat and thereby too additional opening forces on the piston. But also a quick closing of the  Valve in case of pressure drop and reduction of the pressure drop is guaranteed. There namely the flow through the piston from the inlet side has a significant effect Flow forces on the piston, which contribute to the quick closing of the valve seat Lead to pressure drop.

The oil emerging between the seating surfaces 4 and 5 passes from the outer lassraum 26 through bores 35 into the center of the piston 2 and from there into the tank connection 25 . The stationary seat body 3 made of soft material is axially clamped by means of an annular cylindrical bushing 15 through its end face 16 . In this case, however, the annular bushing only has contact with the seat body 3 in the outer annular region. The annular sleeve 15 is axially fixed in the valve housing 29 by a cap 36 which can be screwed onto the valve housing 29 .

The described design of the valve seats could lead to the destruction Leakage of the valve that occurs during commissioning until the closing surfaces run in or caused by contamination and in a short time to destroy the valve leads to be avoided completely. The requirements for manufacturing tolerances could be reduced and therefore the manufacture of the valve simplified.

The valve according to Fig. 3 also fulfills the function of protecting an inflow 24 through connection with an outlet chamber 26 and tank port 25. In this respect, reference is made to the preceding description of FIGS. 1 and 2. The inner of the two side flanks of the groove ends in a circumferential, more or less sharp edge, which is formed by the line of intersection of the inner cylindrical or cone-shaped Be side flank with the cone-shaped inner end face of the groove. This creates a precisely defined hydraulically effective area, which can be calculated and dimensioned so that the closing piston is druchausgegli chen or always closes under hydraulic load.

Reference list

1

Seat valve

1

2nd

Closing body, locking piston

2nd

3rd

Closing body, stationary seat body

3rd

4

Closing surface

4

5

Closing surface

5

6

soft material, ring insert

6

7

Groove

7

8th

End faces

8th

the side flanks of the groove

9

Side flanks

9

the groove

10th

Closing direction

10th

11

ring-cylindrical socket

11

12th

Face

12th

the ring-cylindrical socket

11

13

Annular heel

13

of the seat body

14

Face

14

of the annular heel

13

15

ring-cylindrical socket

15

16

Face

16

the ring-cylindrical socket

15

17th

shaft

17th

18th

Guide body

18th

19th

cartridge

19th

20th

Seals

20th

21

Spring chamber

21

22

feather

22

23

Axial channel

23

24th

Pressure room

24th

25th

Tank connection

25th

26

Outlet space

26

27

poetry

27

28

paragraph

28

29

Valve housing

29

30th

Passage

30th

31

poetry

31

32

radial heel

32

33

Support ring

33

lies on

34

head Start

34

Claims (18)

1. Seat valve with a movable closing piston and a stationary seat body, the identically complementary closing surfaces of circular cross-sectional areas with linear or progressively increasing diameter in the closing direction, for. B. are tapered, spherical, paraboloidal and cooperate sealingly when closed by intimate contact and separate the inlet side of the seat valve from the outlet side;
Mark:
the movable locking piston is guided by a straight guide in the closing direction and spring-loaded;
the cross-sectional area of the straight guide is also loaded with the hydraulic inlet pressure on the inlet side in the closing direction. 2. Seat valve with a movable closing piston and a stationary seat body, the identical complementary closing surfaces of circular cross-sectional areas with linear or progressively increasing diameter in the closing direction, for. B. are tapered, spherical, paraboloidal and cooperate sealingly when closed by intimate contact and separate the inlet side of the seat valve from the outlet side;
Mark:
one of the closing bodies (closing piston or seat body) in the area of the seat surface is made of a material which is considerably softer than the material of the other closing body in the area of the seat surface. 3. Seat valve with a movable closing piston and a stationary seat body, the identical complementary closing surfaces of circular cross-sectional areas with linear or progressively increasing diameter in the closing direction, for. B. are tapered, spherical, paraboloidal and cooperate sealingly when closed by intimate contact and separate the inlet side of the seat valve from the outlet side;
Mark:
the movable locking piston is guided by a straight guide in the closing direction and spring-loaded;
the cross-sectional area of the straight guide is also loaded with the hydraulic inlet pressure of the inlet side in the closing direction;
one of the closing bodies (closing piston or seat body) in the area of the seat surface is made of a material which is considerably softer than the material of the other closing body in the area of the seat surface. 4. Seat valve according to claim 1 or 3 features:
the movable locking piston is a hollow cylinder, the end face of which is closed in the area of the seat;
The hollow cylinder is flowed through from the inlet side and has radial openings in front of its closed end through which the pressure chamber surrounding the valve seat is connected to the outlet side. 5. Seat valve according to claim 1 or 3 features:
the straight guide is located on the outlet side in the form of a shaft which seals the outlet side of the valve with respect to the spring chamber connected to the inlet side. 6. Seat valve according to one of claims 2 to 5
One of the closing body (closing piston or seat body) consists of steel in the area of the seat, the other closing body made of a much softer, in particular elastically deformable material, in particular plastic, in particular a plastic which is harder than rubber. 7. Seat valve according to one of claims 2 to 6
The seat surface is so small in the axial direction that the soft material of the closing body deforms to a degree under the closing load, vozugwei se elastically deformed to a degree that exceeds the size of the fitting tolerances of the cooperating closing surfaces. 8. Seat valve according to one of claims 5 to 7;
Mark:
the soft material is embedded in the closing body as a ring insert in a groove such that the sides of the groove form the abutment of the ring insert against the closing force. 9. Seat valve according to one of claims 5 to 8;
Mark:
at least one of the end faces forms an acute angle with the adjacent side flank of the groove such that a circumferential sharp edge is formed between the end face and the groove, which forms the opening lip for the soft material of the ring insert emerging from the groove. 10. Seat valve according to claim 8 or 9
at least one of the side flanks of the groove consists of a material that is plastically deformable under closing load. 11. Seat valve according to one of claims 8 to 10;
Mark:
at least one of the end faces of the side flanks of the groove is permitted by Materialab so that it withdraws as far behind the ring insert in the closing direction that there is no contact between the end faces of the side flanks and the seat of the other closing body when the closing load is applied. 12. Seat valve according to one of claims 8 to 11;
Mark:
one flank of the groove is formed by an annular shoulder of the seat body and the other by the end face of an annular cylindrical bushing which can be locked onto or into the circumference of the seat body, preferably screwed in and screwed on and locked, so that the lateral pressure of the Ring insert is adjustable. 13. Seat valve according to one of claims 2 to 12;
Mark:
the soft material is a ring insert, which rests on an annular shoulder of the seat body in the closing direction and is preferably firmly clamped;
the end face of the annular shoulder comes back as far behind the ring insert in the closing direction that there is no contact between the end face and the seat of the other closing body when the closing load is applied. 14. Seat valve according to claim 13
the end face of the annular shoulder consists of a plastically deformable material under closing load, in particular metal, in particular copper fer alloy. 15. Seat valve according to claim 13 or 14;
Mark:
the end face of the annular shoulder is designed by material removal in such a way that it withdraws so far behind the ring insert in the closing direction that there is no contact between the end face and the seat surface of the other closing body when the closing load is applied. 16. Seat valve according to one of claims 13 to 15;
Mark:
the ring insert is on the annular shoulder of the seat body through the end face of an annular cylindrical socket which is lockable on or in order to catch the seat body, preferably screwed or screwed on and can be locked, so that the lateral pressure of the ring insert is adjustable . 17. Seat valve according to one of claims 2 to 16;
Mark:
the seat made of a hard material is longer in the axial direction, but preferably not more than 2 times, preferably not more than 1/3 to longer than the seat made of a softer material of the other closing body, which is preferably shorter than 4 mm, is preferably shorter than 3 mm. 18. Seat valve according to one of claims 2 to 17;
Mark:
the closing body, which in the area of the seat consists of a material that is significantly softer than the material of the other closing body in the area of the seat, is the seat body.