DE102022132295A1 - Check valve and manufacturing process - Google Patents

Abstract

The present invention relates to a check valve (1) comprising a valve flap (5) which, in a closed position, closes a flow opening (3) by sealingly abutting a sealing surface (4), and a manufacturing method therefor. In order to create a check valve with a simplified structure, it is proposed that the check valve (1) comprises a disk (2) made of an elastic plastic, wherein a clamping edge (7) of the disk (2) defines a plane (10), in which plane (10) a cut (6) running through the disk (2) is provided, wherein the cut (6) forms the valve flap (5) and a connection point (9) through which the valve flap (5) is connected to the disk (2), and a cut surface of the cut (6) forms the sealing surface (4) of the check valve (1).

Description

The present invention relates to a check valve and a method for its production.

It is known that in a check valve a closing element is closed in one direction, e.g. by a spring load, and pressed against a sealing seat, while in the opposite direction it is released by the pressure of a flowing fluid. A known check valve comprises a valve flap which is arranged in a closed position on a sealing surface of a flow opening by sealingly engaging it.

Currently, check valves are usually produced in a multi-material injection molding process on complex injection molding tools made of a multi-material composite or with complex technology in connection with valve balls and springs, even when meeting high purity requirements and with high demands in terms of chemical resistance. Chemical resistance is extremely difficult to achieve in this case, so that the production of the individual parts in question and their assembly is either very complex and expensive, or only cost-effective in large quantities. Known check valves are a major disadvantage due to their construction from various different components, especially for applications such as in intensive care medicine or semiconductor technology. In these areas, cone check valves made of rubber are usually used, which are difficult to control. These check valves can only be manufactured using injection molding technology and only with a limited maximum blocking pressure.

The present invention has the task of creating a check valve that has a simple structure and a compact design and can therefore be manufactured cost-effectively. It should also be usable as a check valve for pumping a fluid medium in extremely small applications with high purity requirements and high chemical resistance.

The above-mentioned object is achieved according to the invention by the features of claim 1 in that the check valve comprises a disk made of an elastic plastic, wherein the clamping edge defines a plane and a cut is provided in the plane running through the disk. The cut forms the valve flap and also forms a connection point through which the valve flap is connected to the plane. A cut surface of the cut also forms the sealing surface of the check valve.

Furthermore, a manufacturing method according to claim 9 also represents a solution to this problem.

The present invention is based on the knowledge that a check valve in the form of a check flap is less complex to build than a ball or disk valve, in which a respective sealing element must be guided axially and possibly loaded with elastic springs, due to a sealing plate or valve flap that is pivotable on one side. According to the invention, the sealing flap is advantageously linked together with the provision of a spring-elastic restoring force acting on the sealing plate in the direction of a closed position through a connection point. The cut running through the disc forms the valve flap and the connection point as well as the sealing surface. The proposed check valve is also made of a single material and is constructed in one piece.

Special requirements, such as chemical resistance, sterility and ultra-pure requirements, but also small installation space or miniaturization, are thus much easier to meet than with known check valves.

Advantageous further developments are the subject of the dependent claims. Accordingly, the cut is at an angle α to the adjacent surface of the sealing flap, with the angle being in an interval of approximately 10°< α ≤ 90°. The sealing surface formed by the cut surface is therefore larger than a diameter of the disk. In addition, the sealing flap can be mechanically supported on the sealing surface in the closed position and can therefore withstand higher pressures.

According to an advantageous development of the invention, the section has an angle β < 360° measured from a central axis of the plane. This angle β allows a width of the connection point and thus, for a given thickness and property of the material of the disc, an elasticity or spring stiffness of the articulation of the valve flap to be adjusted.

According to one embodiment of the invention, the plane merges into an elevation, with at least one recess located beneath the elevation.

Preferably, the elevation is rotationally symmetrical. In particular, the elevation is shaped as a plateau, wherein the plateau has a surface that runs parallel to the plane defined by the clamping edge of the disk.

In a further development of the invention, the cut is made at a transition from the plane to the elevation is provided. The cut is preferably aligned parallel to the plane. In one embodiment, the cut is at a distance from the plane.

In one embodiment of the invention, several recesses are provided under the elevation. According to a further development of the invention, the several recesses in the plane defined by the clamping edge of the disc together form at least one cross member or strut, which lies under the valve flap due to the cut. In an embodiment described below, such a strut serves in the form of a connection point as an elastic linkage for a valve flap. Alternatively, such struts can also be shaped to form a sieve plane upstream of the valve flap in the flow direction, as is also shown below using an embodiment.

Preferably, the clamping edge is designed as a seal, in particular as a sealing edge of a flange seal. However, the clamping edge can also be adapted to other types of sealing fixation of the check valve.

A method for producing a check valve according to one of the features specified above is characterized in that the disk is made of an elastic plastic as a turned and/or milled part from bar stock or alternatively as a product of an injection molding process. In this case, the at least one cut for forming at least one sealing flap with articulation by a connecting part and for forming at least one sealing surface is produced without cutting. This cut is produced without cutting and is produced in particular by defined piercing or cutting.

In a further development of the manufacturing process, the sealing flap is reshaped by aging at high temperatures and/or by hot stamping with over-stamping. This compensates for any possible bulging of the sealing flap at the end of the manufacturing process.

The above description describes a single-material, one-piece check valve which, due to its design, can be manufactured easily and cost-effectively across all versions. Due to its compact design, this check valve can be used as a check valve in the smallest of applications for pumping, while also reliably meeting the highest requirements for purity and/or sterility as well as high resistance to chemically aggressive substances.

• 1: eine Schnittdarstellung entlang einer Längsachse eines ersten Ausführungsbeispiels eines Rückschlagventils in Form einer Rückschlagklappe in einer Einbaulage;
• 2: eine Draufsicht auf das Rückschlagventil von 1 in Durchflussrichtung;
• 3: eine Draufsicht auf ein zweites Ausführungsbeispiel eines Rückschlagventils in Form einer Doppelflügel-Rückschlagklappe in Durchflussrichtung;
• 4: eine Schnittdarstellung einer Ebene A-A von 3;
• 5: eine Darstellung eines dritten Ausführungsbeispiels eines Rückschlagventils in einer seitlichen Schnittansicht in einer Ebene B-B;
• 6: eine Draufsicht auf eine Rückschlagklappe gemäß dem Ausführungsbeispiel von 5 in Durchflussrichtung;
• 7: eine Draufsicht auf ein viertes Ausführungsbeispiel eines Rückschlagventils mit einer in Durchflussrichtung vorgelagerten Siebebene und
• 8: eine Schnittdarstellung einer Ebene C-C von 7.

Further features and advantages of embodiments according to the invention are explained in more detail below with reference to exemplary embodiments based on the drawing. In this drawing, in a schematic representation:

• 1 : a sectional view along a longitudinal axis of a first embodiment of a check valve in the form of a check flap in an installation position;
• 2 : a top view of the check valve of 1 in flow direction;
• 3 : a plan view of a second embodiment of a check valve in the form of a double-wing check valve in the flow direction;
• 4 : a sectional view of a plane AA of 3 ;
• 5 : a representation of a third embodiment of a check valve in a side sectional view in a plane BB;
• 6 : a plan view of a check valve according to the embodiment of 5 in flow direction;
• 7 : a plan view of a fourth embodiment of a check valve with a screen plane upstream in the flow direction and
• 8th : a sectional view of a plane CC of 7 .

The same reference numerals are used for the same elements throughout the various illustrations in the drawing. Without limiting the invention, only one use of embodiments of the invention is shown and described below against the background of the use of a check valve in food and medical technology. However, it is obvious to the person skilled in the art that one of the valves described below can also be adapted in the same way, e.g. for clean room applications for chip production on the one hand, as well as for mass products in the form of small pump dispensers for disinfectant solutions or washing lotions in the cosmetics or sanitary sector, and even for applications with special hygiene requirements, e.g. in medical, pharmaceutical or food production.

The illustration of 1 shows a sectional view along a longitudinal axis of a first embodiment of a check valve 1 in the form of a flat disk 2 made of an elastic plastic with a valve or check valve arranged sealingly adjacent to a sealing surface 4 in a closed position. flap 5. The sealing surface 4 is formed by a cut 6 running through the disc 2, which is at an angle α with 10°< α ≤ 90°, here approx. 60°, to the adjacent surface of the sealing flap 5. Due to this inclination, a length L of the cut 6 is greater than a thickness d of the disc 2. In addition, the sealing flap 5 is in the 1 shown closed position onto the sealing surface 4, so that a considerably increased sealing effect and an improved mechanical stabilization of the sealing flap 5 are achieved compared to a vertical cut with α = 90°.

The check valve 1 is in the 1 indicated installation position in a flange between two sketched pipe sections. For this purpose, the disk 2 comprises a clamping edge 7, which is also designed as a seal here, in particular as a flange seal with opposing sealing surfaces 8. In addition, the clamping edge 7 has sealing surfaces 8, which are designed in the manner indicated by corresponding recesses for bolts for sealingly fixing the check valve 1 between the flange ends by screwing. When used between pipe sections screwed together, these bolt holes in the sealing surfaces 8 can be omitted. In order to optimize the size of a flow opening 3, in this embodiment the cut 6 for forming the sealing surface 4 has been arranged almost immediately adjacent to the clamping edge 7 so that the sealing flap 5 can move freely at all times.

2 shows a plan view in the flow direction of the check valve 1 of 1 The check valve 1, which is made of a single material and in one piece from the disk 2 of an elastic plastic, is formed by making the cut 6 to form the sealing surface 4, the valve flap 5 and a connection point 9. In this embodiment, the cut 6 has an angle of 180° < β ≤ 360° measured from a central axis M of the disk 3, here with β approx. 330°. The 30° remaining to form the full circle form the connection point 9, through which the valve flap 5 is connected in a plane 10 of the disk 2 defined by the clamping edge 7 in the area of the clamping edge 7.

The connection point 9 is elastic due to the material selected for the disk 2 and guides the valve flap 5 close to the clamping edge 7. The expert is aware of measures for influencing bending behavior in the area of the connection point 9 and/or defining a bending line, e.g. by means of an incision 11, an elongated notch or other targeted thinning or weakening of the material. The connection point 9 forms a guide for the valve flap 5 relative to the sealing surface 4 as an elastic link with a certain spring stiffness and must be movable in the exemplary embodiments considered solely by means of a pressure difference.

3 shows a plan view of a second embodiment of a check valve 1 in the form of a double-wing check valve in the flow direction. A surface of the check valve 5 of 1 has been roughly halved here, whereby in the embodiment according to 3 Two non-return valves 5` are now provided, each of which is elastically connected via a connection point 9 of a cross strut 12 running over the flow opening 3. This means that two cuts 6 with β < 180° each at the same angle α as in 1 intended.

4 is a sectional view of a plane AA of 3 Here, curved arrows indicate the directions of movement of the check valves 5' of a double-wing check valve 1 when actuated in the flow direction, analogous to the illustration of 1 indicated.

All embodiments described above are based on a flat disk 2, i.e. a disk 2 with a constant thickness d. 5 now shows a representation of a side view of a third embodiment of a check valve 1 in the form of a further double-wing check valve as a modification of the embodiment of the 3 and 4 . In this embodiment, it is characteristic that a plane 10 defined by the clamping edge 7 merges into a rotationally symmetrical dome-shaped or plateau-like elevation 13, with two recesses 14 arranged symmetrically to one another under the elevation 13 in this embodiment. The cut 6 is provided at a transition from the plane 10 of the clamping edge 7 into the elevation 13 at an angle α = 90° or parallel to the plane 10 of the clamping edge 7 and thus opens the recesses 14, which thus become through-flow openings 3. The through-flow openings 3 are separated by a cross strut 12.

6 shows a top view of the embodiment of 5 This shows the course of section 6, through which elevation 13 is separated in the manner of a plate with β = 360° and only over the area defined by horizontal hatching in 6 marked almost circular connection point 9 remains connected to the cross strut 12. The two halves of this plate behave in relation to the two recesses 14 opened by the cut 7 like the check valves 5 of a double-wing check valve.

7 shows a plan view of a fourth embodiment of a non-return valve 1. In further development of a structure known from the third embodiment of a disc 2 with a plateau-like elevation 13, numerous recesses 14 are now provided here, each of which is cylindrically shaped.

As from 8th with a sectional view of a plane CC of 7 It can be seen that the cut 6 is again provided at the transition from the plane 10 of the clamping edge 7 to the elevation 13 at an angle α = 90°, but now at a distance a parallel to the plane 10 of the clamping edge 7 and forming a connection point 9 in the form of a circular segment marked with horizontal hatching, comparable to the connection point 9 of the first embodiment, see 1 and 2 . Through this cut 6, the recesses 14 form an approximately grid-like structure, which is arranged in front of the check cap 5 in the direction of flow when passing through in the manner of a coarse sieve. A surface structure is thus arranged on the check valve 5 directed towards the sealing surface 4, which can provide additional mechanical stiffening as a structural measure with a slight increase in the weight of the check valve 5.

A method for producing a check valve 1 according to one of the features specified above is characterized in that the disk 2 is made from an elastic plastic as a turned part from a rod material. The recess 14 of the third and fourth embodiments are then subsequently produced as millings, or the disk 2 is produced as a milled part in its entirety. Alternatively, the disk 2 is produced in an injection molding process across all of the embodiments described above, so that disks 2 with a non-rotationally symmetrical shape can also be produced here, e.g. rectangular surfaces with a plateau-like elevation 13 of any shape at different distances from a clamping edge 2, in order to show examples of the freedom that can be used in the design of a check valve 1.

In all manufacturing processes, however, the at least one cut 6 for forming at least one sealing surface 4 and at least one sealing flap 5 corresponding to the sealing surface 4 is produced without cutting, in particular by piercing or cutting through the material of the disc 2. The shape of the sealing flap 5 achieved after this work step is of great importance for the functionality of the check valve 1. In a neutral position, the sealing flap 5 should rest as completely as possible on the sealing surface 4. Internal mechanical stresses in the material of the disc 2 can, however, lead to the sealing flap 5 being curved after the cut 6 has been made or deviating in some other way from the desired shape. The sealing flap 5 is therefore reshaped if necessary by aging at high temperatures and/or by hot stamping with over-stamping.

In any case, a manufacturing process for a check valve 1 according to one of the exemplary embodiments described above involves significantly fewer work steps compared to known processes. The end product of a manufacturing process specified here is a single-material and one-piece check valve 1 with a very compact design, which can also meet high requirements for sterility up to clean room regulations with little effort.

Check valves according to the embodiments described above are exposed to overpressures of 0.3 bar to 6 bar. The delivery quantities to be handled by a check valve 1 according to the invention are very low in the semiconductor sector with dosing units of a few µl and in the diaphragm pump sector they are sometimes very high with up to 500 l/min.

A range of elastic materials are available for the application examples mentioned. PTFE is particularly preferred for machining. PFA, FEP and PVDF can also be used as materials for a check valve according to the invention. Solutions made of PE and especially UHMW PE can be used sensibly for cost-effective check valves as products in extremely high quantities.

The diameters of the respective disks 2 made of an elastic plastic range from approx. 5 mm to over 50 mm. For manufacturing reasons, the respective thickness of the flexible valve/sealing/check valve 5 is approx. 0.3 mm and for special applications up to a thickness of approx. 3 mm. Smaller check valve seals are used primarily in hose equipment for conveying aggressive media, e.g. acids, alkalis and cleaning agents, and for metering pumps in the semi-conductor sector. Larger check valves are mainly used in diaphragm pumps for aggressive media or for special hygiene requirements, such as in the cosmetics or food industry in particular. Due to the one-piece construction, a check valve 1 according to one of the exemplary embodiments described above is characterized by a small installation space and is also very easy to clean.

List of reference symbols

1

check valve

2

Disc made of an elastic plastic

3

Flow opening

4

Sealing surface

5

Valve/sealing/check valve

5'

Check valve of a double-wing check valve

6

Section through the pane 2

7

Clamping edge

8th

Sealing surface of the clamping edge 7

9

Connection point

10

Plane defined by the clamping edge 7

11

Incision in the area of the connection point 9

12

Cross brace / grille

13

Survey

14

Recess under the elevation 13

α

Angle of cut 6 relative to the adjacent surface of the sealing flap 5, 5`

β

Circumferential angle of cut 6

a

Distance

d

Thickness of disc 2

L

Length of section 6 through disc 2 or length of sealing surface 4

M

Central axis of the rotationally symmetrical arrangement.

Claims (10)

Check valve comprising a valve flap (5) which, in a closed position, is arranged on a sealing surface (4) to close a flow opening (3) by sealingly abutting it, characterized in that the check valve (1) comprises a disk (2) made of an elastic plastic, wherein a clamping edge (7) of the disk (2) defines a plane (10), in the plane (10) a cut (6) running through the disk (2) is provided, wherein the cut (6) forms the valve flap (5) and a connection point (9) through which the valve flap (5) is connected to the disk (2), and a cut surface of the cut (6) forms the sealing surface (4) of the check valve (1). Check valve according to the preceding claim, characterized in that the cut (6) is at an angle (α) of 10°< α ≤ 90° to the adjacent surface of the sealing flap (5). Check valve according to one of the preceding claims, characterized in that the section (6) has an angle (β) ≤ 360° measured from a central axis (M). Check valve according to one of the preceding claims, characterized in that the plane (10) merges into an elevation (13), and at least one recess (14) is located under the elevation (13). Check valve according to the preceding claim, characterized in that the elevation (13) is rotationally symmetrical, in particular is shaped as a plateau. Check valve according to one of the preceding Claims 3 and 4 , characterized in that the cut (6) is aligned parallel to the plane (10) and preferably has a distance (a) from the plane (19). Check valve according to one of the preceding Claims 3 until 5 , characterized in that a plurality of recesses (14) are provided under the elevation (13). Check valve according to one of the preceding claims, characterized in that the clamping edge (7) is designed as a seal and in particular has sealing surfaces (8) of a flange seal. Method for producing a check valve according to one of the preceding claims, characterized in that the disc (2) is produced from an elastic plastic as a turned and/or milled part from rod material or as a product of an injection molding process, wherein the at least one cut (6) for forming at least one sealing flap (5) and at least one sealing surface (4) is produced without chipping, in particular by piercing or cutting. Method according to the preceding claim, characterized in that the sealing flap (5) is reshaped by aging at high temperatures and/or by hot stamping with over-stamping.

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