EP0749531A1

EP0749531A1 - Compressor valve

Info

Publication number: EP0749531A1
Application number: EP95916496A
Authority: EP
Inventors: Leopold Böswirth
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-04-27
Filing date: 1995-04-26
Publication date: 1996-12-27
Anticipated expiration: 2015-04-26
Also published as: WO1995029338A1; ATE164426T1; AU2297995A; EP0749531B1; DE59501718D1

Abstract

A valve for reciprocating piston compressors designed without a stop for the valve reed (1) has a component (4) with several channels (10) arranged at the side of the valve seat plate (2) opposite to the valve reed (1). Each channel (10) of the component (4) is aligned with a throughflow opening (9) in the valve seat plate (2). The high speed level in the relatively narrow channels (10) of the component reduces the fluttering movements of the valve reed (1) and the speed at which the valve reed (1) hits the valve seat plate (2). The stroke of the valve reed (1) is exclusively limited by its suspension springs.

Description

COMPRESSOR VALVE

The invention relates to a valve as a suction or pressure valve for piston compressors with a valve seat plate, in which at least one passage opening is arranged, and with a spring-loaded valve plate or valve lamella which is movable relative to the valve seat plate and which is arranged on the downstream side of the valve seat plate is, the valve plate or valve lamella closes the passage opening in the currentless state, and is lifted off the valve seat plate under the action of the medium flowing through the valve.

Such valves are known as suction and pressure valves for reciprocating compressors. In the known valves for Hulb piston compressors, specifically both in valves in which essentially rigid valve plates are used, and in valves of the type with a spring-elastic deformable valve lamella ("lamellar valves"), as are used for example for refrigerant compressors To limit the stroke of the valve plate or the valve lamella away from the valve seat plate, stroke catchers which are rigidly connected to the valve are provided.

A disadvantage of these known valves for reciprocating piston compressors is that the valve plate or valve lamella have impact effects which reduce the life of the valves. It has therefore already been proposed to arrange damper plates in the case of ring plate valves between the valve plate and the lift catcher in order to reduce the impact effects.

Furthermore, the stroke catchers in suction valves are disadvantageous insofar as they enlarge the dead space.

The invention has for its object to develop a valve that can be used as a suction and pressure valve for reciprocating compressors, so that the maximum stroke of the valve plate or valve lamella is effectively limited even without a stroke catcher and that dangerous fluttering of the valve plate or Valve lamella before the seat cushion be dampened.

According to the invention this is achieved in that the movement of the valve plate or valve lamella away from the valve seat plate is limited solely by the spring force acting on the valve plate or the elasticity of the valve lamella, that a component with a channel is connected upstream of the valve seat plate following the passage openings in the valve seat plate is provided, which is aligned with the passage opening in the valve seat plate, that the cross-sectional area of the channel is substantially the same size as the cross-sectional area of the passage opening and that the ratio of the length of the channel to the hydraulic diameter of the flow cross-section of the channel is between 1 and 10.

In the valve designed according to the invention, the stroke of the valve plate or valve lamella is no longer limited by a stroke catcher, but only by the spring (at least one) assigned to the valve plate or the spring properties of the valve lamella itself.

Due to the gas mass contained in the channel (or in the case of several passage openings in the channels), the flow velocities change only with a considerable delay compared to the pressure differences, which results in an effective damping of flutter vibrations.

Furthermore, a reduction in the mass of the valve plate which is possible with the invention has a strong damping effect on the flutter vibrations, so that the length of the channel required for the effective damping can be selected to be smaller.

The exact dimensioning of the length of the channel, the mass of the valve plate or the valve lamella and the spring force acting on them can be done, for example, with the aid of computer programs which simulate the valve plate movement and with the aid of control tests.

When using valves designed according to the invention, more compact, faster-running piston compressors with Realize lower valve-related losses and a longer valve life.

From DE-C-903 735 and US-A-2 620 125 valve arrangements have become known which, on the valve chamber side, attach a tube-like or channel-like extension to the entire valve, the length of which extends on the so-called λ / 4 tube oriented according to the spring-mass natural frequency of the valve. A resonance effect of the compressible gas column in the λ / 4 tube dampens fluttering of the valve plate. For typical spring-mass natural frequencies in valves, the length of the λ / 4 tube is given as approximately 0.5 m, which requires impractical, space-consuming constructions.

In contrast, the valve according to the invention uses the inertia effect of the gas in the channel, which in practice is only a few centimeters long, which is composed of the passage opening in the valve seat plate and the component provided for channel extension. The application of a duct extension directly to the duct or the ducts of a valve - not to the entire valve - is essential for the targeted utilization of the inertia effect of the gas column, just like the narrow duct cross-sectional areas oriented at the passage opening in the vent plate. In contrast, the λ / 4 tube in the above-mentioned patents has an approximately ten times larger cross-sectional area.

Preferred and advantageous embodiments of the valve according to the invention are the subject of the dependent claims.

Further features and advantages of the invention result from the following description of exemplary embodiments of valves according to the invention, which are shown in the drawings.

1 shows a suction valve for a piston compressor in axial section,

2 shows a detail of the valve from FIG. 1 in another embodiment, 3 shows a detail of a suction valve with valve lamella,

4 shows a detail of a pressure valve with valve lamella,

5 in a common representation two embodiments of a suction valve with valve plate,

6 a pressure valve with valve plate,

Fig. 7 shows another embodiment of a pressure valve with valve plate and

FIGS. 8 and 9 each have three diagrams for the valve plate movements of suction valves.

Fig. 1 shows in axial section a ring plate valve which is designed as a suction valve. A valve plate 1 seals the cylinder space (in FIG. 1 below the valve) against the valve chamber by resting on the downstream surface on a valve seat 2. Both the valve plate 1 and the valve seat 2 are designed in terms of strength in accordance with the pressure difference to be sealed. A spring support 3 is fastened to a central screw 6 of the valve, in which several compression coil springs 8 are supported, which press the valve plate 1 against the valve seat 2. The distance of the spring support 3 from the valve seat 2 is selected so that the valve plate 1 does not strike the spring support 3 even in its open position, so that its stroke is limited only by the force of the springs 8. In a practical embodiment of the valve according to FIG. 1, this distance can be 6 mm, for example.

On the side facing away from the valve plate 1, a component 4 is placed on the valve seat 2, in which channels 10 are provided that are aligned with each of the through openings 9 in the valve seat 2. The component 4 is attached to the central screw 6 of the valve with the aid of an adapter sleeve 5 and a nut.

The component 4 and thus the channels 10 provided in it are in a practical embodiment a few centimeters long. In terms of strength, no special requirements are imposed on the component 4 and it can be designed as a plastic or metal pressed part or also as a sheet metal part. The component 4 can also, as shown in FIG. 2, be composed of individual ring elements or tubular hollow cylindrical elements and, if appropriate, also of a plurality of parts placed one above the other, as is also shown in FIG. 2.

The valve according to FIG. 1 has about three times the gas inertia effect as without the component 4.

It should also be pointed out that two suction valves connected in parallel according to FIG. 1 with an installation diameter of 100 mm form the basis of the simulation results shown in diagrams 3 to 6 of FIGS. 8 and 9.

3 and 4 show possible designs for lamella valves, the lamella 11 taking over the function of the valve plate and spring, as is known per se. A spring support is not required in the embodiment of the lamella valve according to the invention. A suction valve is shown in FIG. 3 and a pressure valve in FIG. 4. In the latter case, the component 4 with the channel 10 does indeed result in additional damage space, but this can be kept low by channel insertion, which also increases the gas inertia effect and thus reduces the required length of the channel 10.

The spring constants of the springs 8 of a valve according to the invention without a stroke catcher generally do not need to be significantly larger than in a conventional valve with a stroke catcher. Because of the larger spring travel when the valve plate moves freely in the lifting field, this usually results in springs with larger dimensions. In many cases, construction sizes result which are comparable to the valve springs used in car engines. Instead of a plurality of springs 8 loading the valve plate 1, a single spring concentric to the valve plate 1 can also be provided, as will be explained later in exemplary embodiments. In certain applications, it can be disadvantageous to support the springs 8 loading the valve plate 1 in a separate spring support 3. With regard to a good use of space with regard to damage space in suction valves and with regard to a compact cylinder construction, it can be provided in the valve according to the invention that the spring or the springs are supported on components which surround the valve plate 1. For example, the springs or the spring can be supported on depressions in the suction valve installation pocket walls or on console-like projections of the pressure valve hold-down lantern.

5 shows the spring support in a suction valve according to the invention by way of example in two embodiments. In Fig. 5 left the support of a concentric single spring 12 is shown in a recess 13 in the bottom of the valve recesses. A separate spring support 3 is no longer required in this embodiment. The spring preload can be adjusted by means of small plates 14.

As an alternative embodiment, a separate spring support 15, which is shown in broken lines in FIG. 5, can be inserted into the valve installation pocket.

In FIG. 5 it is also shown that a stop for the valve plate 1 can be provided by a protruding head 16 on the central screw 6 in the event of a spring break or other emergency operating conditions.

5 on the right shows a springing of the valve plate 1 consisting of three springs 8 arranged on the valve plate circumference offset by 120 °. The springs 8 are supported on a spring support 17 placed in the bottom of the valve installation pocket, which is fixed with screws 18. Here too, washers 14 can be provided to adjust the spring preload.

6 and 7 show two embodiments for pressure valves designed according to the invention for reciprocating compressors. The embodiment shown in FIG. 6 has three springs 8 arranged at 120 ° to each other, which are supported on bracket-like projections 21 of a hold-down lantern 20.

In the embodiment shown in FIG. 7, a compression coil spring 12 concentric with valve plate 1 is provided. The spring 12 is supported on a twisted projecting board 22 of the hold-down lantern 20. In the pressure valve shown in FIG. 7, the arrangement of the component 4 with the channels 10 does result in an increased clearance. However, this increase can be kept small by using a particularly light valve plate 1, which reduces the required length of the channels 10 in order to have a damping effect. A reduction in the clearance in the valve installation can also be achieved in that the channels on the inflow side are drawn somewhat towards the valve axis.

8 shows three diagrams of the valve plate movement of suction valves, which have been calculated with the aid of a computer simulation program. The diagrams are based on data from an industrial gas compressor with the following main data.

Stroke / piston diameter / speed: 0.18m / 0.18m / 500min suction pressure / gas density / pressure ratio 50 bar / 45.2 kg / m / 2.5 average piston speed 3.0 m / sec

Two suction valves, each with 0.97 m seat edge length and a flow coefficient of 0.50.

Diagram 1 of FIG. 8 shows the calculated movement of the valve plate of a conventional valve, the valve plate stroke being assumed to be limited to 1.2 mm by a stroke catcher. The calculation again results in a speed of the valve plate striking the stroke catcher of 2.6 m / sec and a seat impact speed of 0.4 m / sec, the valve-related energy loss being 3.64% of the isentropic compression work.

Diagram 2 of FIG. 8 contains identical data as the diagram 1, but the stroke catcher has been assumed to be ineffective. The valve plate flutters violently and reaches strokes of up to about 5 mm, with 12 seat cushions with impact speeds of up to 3.7 m / sec.

Diagram 3 of FIG. 8 shows the calculated movement curve of valve plate 1 of a valve according to the invention (valve according to FIG. 1). The valve plate 1 moves freely in the lifting field, with flutter vibrations being strongly damped due to the construction of the valve according to the invention, and the valve plate 1 only resting on the valve seat 2 at a speed of 0.11 m / sec. The valve-related loss work is only 2.29% of the isentropic compression work.

Compared to Diagrams 1 and 2, the spring constant of 100,000 N / m was taken over unchanged for the simulation calculation, the valve plate mass (compared to Diagrams 1 and 2) was reduced to 60% and a channel extension assumed, which reduced the gas inertia effect to three times ( compared to a valve seat plate alone) increased. The diagrams shown in FIG. 8, created by computer simulation, for the valve plate movement in the suction valve of an industrial gas compressor (working pressure 50 bar, 2 valves according to FIG. 1, connected in parallel) show the idealized movement sequences in the broken lines mass-accepted valve plate. The solid lines are the result of solving the motion differential equation for a realistic model of a valve-compressor arrangement.

The calculated valve plate movement diagrams from FIG. 9, which are based on identical data as in diagram 3 of FIG. 8, show that the valve designed according to the invention also has a favorable speed behavior. Only the speeds were changed.

Speed, average piston speed, seat impact speed and valve-related loss work in% of the isen¬ tropic compression work are calculated as follows. Speed of the middle piston seat-valve-related speed speed dissipation in% of the isentropic compression work

Diagram 4 375 / min 2.25 m / sec 0.062 m / sec 2.02

Diagram 5 750 / min 4.5 m / sec 0.248 m / sec 2.79

Diagram 6 1000 / min 6.0 m / sec 0.44 m / sec 3.24

Even at the high, average piston speed of 6 m / sec, there are very favorable values for the impact speed of the valve plate 1 and for the valve-related energy loss.

Dimensioning experiments with a computer simulation program for the valve according to the invention resulted in the following:

1. For medium and high pressure valves, the length of the channels 10 is a few centimeters, approximately with the proportions shown in FIGS. 1-7. For a valve with an installation diameter of 100 mm and a 2 mm thick valve plate 1 made of steel, this results in an approximately 5 cm long channel extension through component 4. If the valve plate made of 2 mm steel is replaced by a 3 mm thick plastic plate, which is only 1 / 3 of the mass of the steel plate, a channel extension through the component 4 by one centimeter is sufficient.

2. The lower the speed of sound of the gas to be compressed (working gas), the shorter the required lengths of the channels 10 in the component 4.

3. In the case of low-pressure valves in the form of ring plates with their valve plates, which are relatively heavy in terms of their gas density, there are generally long passages 10 in the component part 4. By accepting somewhat higher valve-related loss work, ie using stronger springing (springs 8 or 12), it is also possible here the length of the channels 10 is reduced to a few centimeters, in any case to values below 10 cm. Favorable conditions for valves for low pressure compressors offer particularly light valve plates or lamellar valves or low sound speeds for the gases to be compressed, for example refrigerant vapors.

In summary, the invention can be represented as follows, for example:

A valve for reciprocating compressor designed without a catcher for the valve plate 1 has a component 4 on the opposite side of the valve seat plate 2 on the valve plate 1 with a plurality of channels 10, one of which is aligned with a flow opening 9 in the valve seat plate 2. The high speed level in the comparatively narrow channels 10 in the component 4 reduces fluttering movements of the valve plate 1 and the speed with which it hits the valve seat plate 2. In the case of the valve, the stroke of the valve plate 1 is limited solely by its feathering.

Claims

Claims:

1. Valve as suction or pressure valve for piston compressors with a valve seat plate, in which at least one passage opening is arranged, and with a spring-loaded valve plate or valve lamella, which is movable relative to the valve seat plate, and which is arranged on the downstream side of the valve seat plate, the Valve plate or valve lamella closes the passage opening in the currentless state, and is lifted off the valve seat plate under the action of the medium flowing through the valve, characterized in that the movement of the valve plate or valve lamella away from the valve seat plate exclusively by means of the the spring force acting on the valve plate or the elasticity of the valve lamella is limited so that a component with a channel is provided upstream of the valve seat plate after the passage openings in the valve seat plate, said channel having the passage opening in the valve seat plate aligns that the cross-sectional area of the channel is substantially the same size as the cross-sectional area of the passage opening and that the ratio of the length of the channel to the hydraulic diameter of the flow cross-section of the channel is between 1 and 10.

2. Valve according to claim 1, characterized in that the valve seat plate and the component having the channel are integrally formed.

3. Valve according to claim 1 or 2, characterized in that the at least one spring loading the valve plate is supported laterally outside the valve.

4. Valve according to claim 3, characterized in that the spring is supported on a suction valve at the bottom of the valve installation pocket.

5. Valve according to claim 3, characterized in that the spring is supported in a pressure valve on side shelves or brackets of a hold-down lantern.

6. Valve according to one of claims 1 to 5, characterized gekenn¬ characterized in that the at least one spring is supported on a Federträ¬ ger, which is at least directly rigidly connected to the valve seat plate.

7. Valve according to one of claims 1 to 6, characterized gekenn¬ characterized in that a concentric to the axis of the valve helical compression spring is provided, which load the valve plate in its closed position.

8. Valve according to one of claims 1 to 6, characterized gekenn¬ characterized in that several helical compression springs are provided which load the valve plate in its closed position.