RU2697783C1 - Automatic check valve of low pressure - Google Patents

Abstract

FIELD: valve industry.

SUBSTANCE: invention relates to the field of valves, in particular to check valves of low pressure, intended for use in shutoff pipeline valves for shutting back flow of liquid and gaseous media. Automatic low pressure check valve consisting of front and rear hermetically connected housing parts to form inner cylindrical boring cavity with annular seat for spring-loaded spring return shutoff element by its sealing ring installed in groove on shutoff element. On the side surface of the shutoff element there are several, preferably three, identical guides of centering radial ledges uniformly along the circumference, oriented along the longitudinal axis of the body for centering of the locking element in the cylindrical cavity of the body with possibility of sliding ledges along it. Shutoff element in the form of rotation body has conical front part. Retaining spring locking element is located under radial projections and has stops in rear part of locking element and in mating seat in inner cavity of valve body. Body parts have threads at their ends for connection with supplied external pipes. Shutoff element has a generally streamlined shape with a conical rounded front part coupled with a stepped cylindrical surface, having a groove, in which the above sealing ring is installed, additionally resting against the end of the next side surface, on which the above said centering radial projections are located. Said lateral surface has smoothly decreasing diameter and flat end face for return spring thrust; at that rear part of shutoff element adjoins said platform with cylindrical section of guide to seat said return spring and end conical section with rounding at end.

EFFECT: increased coaxiality of the shutoff element and the housing, and consequently, reduced vibrations, increased service life of valve parts and reduced vortex formation in medium and noise generated by vortices.

3 cl, 8 dwg

Description

Technical field

The technical solution relates to the field of valves, in particular to low-pressure check valves intended for use in shutoff valves for shutting off the return flow of liquid and gaseous media.

State of the art

Known automatic check valve (RF patent No. 123483, published December 27, 2012). The known device comprises a housing consisting of two threaded parts interconnected and provided with jumpers, a locking element with a sealing element and a return spring. A locking element with a sealing element is installed in each jumper, and a return spring is installed on the side of the sealing element.

The disadvantages of the known device include the relatively small area of the bore at the inlet and outlet of the valve, and, consequently, the overall throughput of the valve. This is due to the presence in the design of jumpers located perpendicular to the direction of flow.

Known low-pressure check valve (Chinese patent CN 202510774 (published 2012-10-31) Low-pressure check valve). The low-pressure check valve contains a valve body, a valve (or synonym: shut-off element) valve, a valve seat, and a compression spring. The valve plug, valve seat and compression spring are respectively located inside the valve body. There is an annular protrusion on the inner wall of the valve body. A guide sleeve is installed at the rear of the housing, which has a central bore for the shutter and several openings on the periphery for passing a fluid flow. The shutter of the valve abuts against one annular protrusion, which is a seat, with one end and is inserted into the central hole of the guide sleeve with the other end. The compression spring is located between the protrusion on the shutter and the end of the guide sleeve. The low pressure check valve has the advantages of simplicity and compact design, ease of installation and good tightness. The housing is made of polytetrafluoroethylene (polytetrafluoroethylene).

The disadvantage of the valve is the presence of a guide sleeve with holes, which occupies part of the area of the bore at the valve outlet, and thereby reduces the valve capacity when compared with similar valves of the same dimensions.

Known check valve according to US patent US2960998 (A) (published 1960-11-22) Check valve - with a conical spring, sealing, centering guides along two channels (inlet (inlet) and outlet (outlet)), the housing is screwed in two parts with seal (sealant equivalent). The direction is carried out directly along the inlet and outlet channel in the centering guides.

The disadvantage of this valve is that the flow area of the open valve in this case is very small, because the centering guides themselves occupy a substantial part of the passage channel. Another drawback is the increased requirements for the accuracy of thread manufacturing, on which halves of the valve body are screwed, because it affects the alignment of the cylindrical surfaces of the inlet and outlet channels along which centering is carried out.

Known check valve according to US patent US 2755816 (A) (published 1956-07-24) Check valves - with the locking element in the seat of the valve body type "cone to the edge", without a sealing ring in the locking element, with a locking spring pressing the locking element By centering the locking element on the inner surface of the housing, the housing is welded in two parts. The locking element is centered by its outer cylindrical surface with protrusions, the fluid passes between the protrusions.

However, a different cone-to-edge sealing principle has been used here, and the valve shut-off element has a flat back and, as a result, is poorly streamlined and has a tendency to vortex the liquid.

The closest analogue (prototype) can be considered a non-return valve according to US patent US 2490511 (A) (published 1949-12-06) Valve seal - with a locking element in the valve body seat, with a sealing ring in the locking element, with a cylindrical locking element pressing spring, centering the locking element on the inner surface of the housing, the housing is screwed in two parts. In this case, the valve consists of parts: the front and rear hermetically connected parts of the body with the formation of an internal boring cavity with an annular seat for seating the spring-loaded locking element with its sealing ring installed in the groove on the locking element, as well as the rod (or pin) in the central hole in the locking element and the liquid-transmitting star (with three beams) inserts in the rear of the valve cavity for reciprocal landing of the return spring and mounting the stem. On the lateral surface of the locking element, several (mainly three) identical guides of centering radial protrusions are arranged uniformly around the circumference, oriented along the longitudinal axis of the housing to center the locking element in the cylindrical cavity of the housing with the possibility of sliding of the protrusions along it. The locking element in the form of a body of revolution has a conical front part. The spring supporting the locking element is located under the radial protrusions in the hole in the locking element and has stops in the flat end of this hole in the locking element and in the star insert in the rear of the inner cavity of the valve body. Parts of the casing have threads at their ends for connection with external external pipes.

However, the valve has a rather complicated design with a stem, and the valve shut-off element has a flat back and, as a result, is poorly streamlined and has a tendency to vortexing of the liquid.

Disclosure of invention

The objective of the invention was the joint improvement of the following characteristics of an automatic low pressure check valve:

- while maintaining the overall dimensions in comparison with close analogues, a significant improvement in the geometry of the flow part of the valve, which leads to a decrease in local hydraulic resistance, an increase in throughput and a decrease in noise;

- improving the manufacturability of parts with their minimum quantity;

- if necessary, the possibility of manufacturing a valve for operation at elevated temperatures.

This problem is solved in that the proposed automatic low-pressure check valve consists of front and rear hermetically connected parts of the housing with the formation of an internal cylindrical boring cavity with an annular seat for seating the spring-loaded return element with its sealing ring installed in the groove on the locking element. On the lateral surface of the locking element, several (mainly three) identical guides of centering radial protrusions are arranged uniformly around the circumference, oriented along the longitudinal axis of the housing to center the locking element in the cylindrical cavity of the housing with the possibility of sliding of the protrusions along it. The locking element in the form of a body of revolution has a conical front part. The return spring supporting the locking element is located under the radial protrusions and has stops in the rear of the locking element and in the return seat in the inner cavity of the valve body. Parts of the casing have threads at their ends for connection with external external pipes. At the same time, the locking element has a streamlined shape with a conical rounded front part mating with a stepped cylindrical surface having a groove in which the specified sealing ring is installed, additionally resting on the rear end face of the next side surface on which the above centering radial protrusions are located. The specified lateral surface has a gradually decreasing diameter and a flat end face for stopping the return spring; moreover, the rear part of the locking element adjacent to this site has a cylindrical section of the guide for landing the above return spring and an end conical section with a rounding at the end. The spring, as a rule, is made conical with an extension to the rear of the housing.

All of the above leads to an increase in the coaxiality of the locking element and the housing, and, consequently, to a decrease in vibrations, an increase in the service life of valve parts and a decrease in the eddy formation in the medium and the noise generated due to the eddies.

The shape of the shut-off element is optimized in computer simulation, taking into account the criterion of minimizing hydraulic losses, vortex formation and, accordingly, reducing the noise of the valve. The shape of the shut-off element allows the redistribution of fluid flows inside the check valve in the required direction. At the same time, the locking element has a pronounced elongated part, which directs the flow and minimizes the turbulence of the passing medium, which minimizes the hydraulic resistance of the valve.

The materials of all valve parts are conventional, used in plumbing systems or low-pressure pneumatic systems (up to 10 atm). In this case, if necessary, a variant of the material of the locking element for use in high-temperature conditions (up to 200-275 ° C) is possible - thermoplastic polyphenylene sulfone (polyphenylene sulfone (PPSU)). In this case, the locking element will be made by casting from PPSU, which will improve its technical and technological characteristics.

The technical solution, characterized by the above set of essential features, as of the filing date of the patent application is unknown to the applicant in publicly available sources of information and therefore may meet the requirements of the condition of "novelty."

The technical solution can be implemented industrially using well-known technical means, technologies and materials and therefore meets the requirements of the "industrial applicability" condition.

List of figures

FIG. 1 is an internal view of the design of the check valve in isometry;

FIG. 2 is a longitudinal section through a check valve;

FIG. 3 - flow sections of the check valve on both sides of the locking element;

FIG. 4, 5, 6 - 3 versions of the evolution of the shape of the valve shutoff element in the process of optimizing its shape using computer simulation;

FIG. 7 - frame simulation computer simulation of the valve with a conditional display of the flow lines of the working medium - liquid or gas;

FIG. 8 is a conventional view of the flow of a working medium around the locking element.

The implementation of the invention

The automatic low-pressure check valve (Fig. 1, 2) contains a housing consisting of a hermetically connected rear part 1 and front part 2, as well as a movable locking element 3, a sealing (elastomeric) ring 4 and a spring 5. The valve is designed to pass the working flow medium (liquid or gas) in only one direction (in Fig. 1, 2 it is from left to right) in the presence of a corresponding differential pressure of the medium. If the pressure in front of the locking element 3 minimally exceeds that behind it (the response threshold of the locking element is mainly determined by the initial preload of the spring), then the ring 4 together with the element 3 moves away from the seat (in the form of a flat end surface perpendicular to the central longitudinal axis of the valve) of the front part 1 case) of the front part 2, compressing the spring 5 and opening the passage to the flow of the working medium between the case and the locking element 3. At the same time, due to the generally streamlined shape of the locking element 3, the movement along eye occurs practically without vortex formation (see. FIGS. 7, 8). In addition, the movement of the fluid flow is practically not impeded by the radial protrusions oriented along the longitudinal axis of the housing on the locking element 3, which reliably and accurately center it in the cylindrical cavity of the housing with the possibility of their sliding on the inner cylindrical boring surface of the housing. When pressure equalization or reverse pressure difference (at the inlet to the valve, the pressure is less than at the outlet), the spring 5 returns the locking element 3 with the ring 4 into tight contact with the saddle of the front part 2 of the housing and blocks the flow path.

The main advantages of the proposed design in comparison with analogues:

1) Reduced valve hydraulic resistance

2) Increased manufacturability of valve parts

Lowering the hydraulic resistance of the valve is achieved by:

1. Increased inlet and outlet cross-sectional areas while maintaining overall dimensions due to the lack of guide (s) of the rod (s) in the locking element and jumpers in the housing. In the proposed valve design, the locking element 3 is centered due to the radial protrusions on it and the reduction in the area of circular passage sections is not observed either at the inlet or at the outlet (see Fig. 3) with overall dimensions the same as for analogues.

2. The streamlined shape of the locking element. In the proposed new design, the streamlined surface of the locking element is constant. Due to the lack of guide rods in the proposed design, it is possible to perform special profile surfaces for smooth separation of the flow when flowing onto the front of the locking element and smooth fusion of the flow when leaving the rear of the locking element. (in general, a smooth change in the area of the passage section leads to less hydraulic loss compared with sudden expansion and sudden narrowing). Also, due to less vortex formation during the flow around the shut-off element, less noise of the device is achieved during operation. The flow patterns of the proposed closure element are shown in FIG. 7, 8. The evolution of the shape of the valve locking element in the process of optimizing its shape using computer simulation is represented by three versions of the locking elements in FIG. 4, 5, 6.

Option 1 (Fig. 4). The first version of the locking element had a streamlined shape at the rear and a flat front. A pin of small diameter was made to center the spring. In this design, the following disadvantages were revealed: Braking of the fluid and unsuccessful redistribution of the flow when it flows onto the flat front of the shut-off element. Large areas of tear-off currents when flowing around the o-ring. Separating from the locking element, the flow does not return to it. Large vortex zones form in the region of the centering pin. The small diameter for landing the spring at the rear of the locking element made the spring very taper, so that it had very non-linear stiffness and was not securely fixed.

Option 2 (Fig. 5). In the second embodiment, a cone appeared in front of the shut-off element for smoothly dissecting the flow. The seat for centering the spring has moved to a larger diameter. Instead of a guide pin, a profile surface was made on the back of the locking element for a smoother flow. In the simulation, the braking zone disappeared, the vortex zones in the rear of the shut-off element were located only at the spring landing site and did not exit into the main flow. During the flow around the sealing ring, a tear-off zone was preserved, due to which the flow, flowing around the locking element, narrowed, pressing against the periphery.

Option 3 (Fig. 6). In the third proposed embodiment, the outer diameter of the o-ring is reduced relative to the outer diameter of the locking element. As can be seen from the flow pattern shown in FIG. 7, the separation zones during flow around the o-ring became small. The stream flows around the shut-off element over a larger area of the bore (a schematic qualitative picture of the flow around the shut-off element is shown in Fig. 8).

In addition to a qualitative assessment of the flow of fluid in the valve, quantitative estimates are also used. The most common in this case is the flow rate of the fluid flowing through the valve when a pressure differential of 1 bar is established on it (throughput with a differential of 1 bar). For option 1, this indicator amounted to 5.2 m ³ / h, and for option 3 - 6.9 m ³ / h, i.e. 25% improvement achieved. The first digit - 5.2 m ³ / h - corresponds to one of the best non-return valves produced today (note: all figures are for a valve with a nominal diameter of 1/2 '' working in cold water). The figures are obtained in real experiments with pilot samples of the valve (at present, pilot samples of the proposed valve have been manufactured, and preliminary tests have shown their high efficiency in operation).

In addition to the foregoing, it is also worth noting an increase in the manufacturability of parts of the proposed valve, which is associated with the simplicity of the shapes of the body parts in the form of rotation forms with continuous surfaces, which greatly facilitates the process of their manufacture. In FIG. 1, 2, 3, the housing is as technologically advanced as a cylindrical one, screwed in two parts onto a sealant and with internal pipe threads of cylindrical ends for connection with supply pipes.

Claims (3)

1. Automatic low-pressure check valve, consisting of front and rear hermetically connected parts of the housing with the formation of an internal cylindrical boring cavity with an annular seat for seating a spring-loaded return element of the locking element with its sealing ring installed in the groove on the locking element; on the lateral surface of the locking element, several, mainly three, identical guides of centering radial protrusions are arranged uniformly around the circumference, oriented along the longitudinal axis of the housing to center the locking element in the cylindrical cavity of the housing with the possibility of sliding of the protrusions along it; a locking element in the form of a body of revolution has a conical front part; a return spring supporting the locking element is located under the radial protrusions and has stops in the rear of the locking element and in the return seat in the inner cavity of the valve body; parts of the body have threads at their ends for connection with external pipes; characterized in that the locking element has a generally streamlined shape with a conical rounded front part mating with a stepped cylindrical surface having a groove in which said sealing ring is installed, additionally resting on the back of the end face of the next lateral surface on which the above centering radial protrusions are located; said lateral surface has a gradually decreasing diameter and a flat end face for stopping the return spring; moreover, the rear part of the locking element adjacent to this site has a cylindrical section of the guide for landing the above return spring and an end conical section with a rounding at the end. 2. The valve according to claim 1, characterized in that the spring is conical with an extension to the rear of the housing. 3. The valve according to claim 1, characterized in that the shut-off element is made of thermoplastic molding polyphenylene sulfone (polyphenylene sulfone (PPSU)).

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