DE1917894A1 - Adjustable throttle device for liquids and gases - Google Patents

Description

Adjustable throttle device for liquids and gases Fluids or fluids, d. H. Energy must be transmitted to liquids or gases be converted quite often into a lower form of state (increased entropy), to meet the requirements of work processes.

Such energy conversion is usually carried out as a pressure reduction of the fluid. In a so-called "throttle process", the potential energy of the fluid is converted into kinetic energy (high speed), then into heat in a process with rapid deceleration (turbulence) through friction. However, not all of the kinetic energy is converted into heat. Some of it creates sound power, more commonly known as throttle noise. The amount of power generated in a fluid system is a function of the fluid velocity. For example, it has been established that the noise level of an open nozzle increases over / gradually with the eighth power of the speed in the range below 1 Mach (speed of sound) with the 6.5th power in the range 1 Ilach. In practice this means that a single opening of the throttle increases the sound power to 256 times if the speed at the throttle is doubled. I) a now the speed in an opening is a function of where h represents the pressure drop generated, it can be seen that increasing the pressure drop to 4 times could cause 256 times the noise. This simple calculation explains why the high pressure reduction required in today's power plants can generate unbearable noise levels in neighboring residential areas. This poor is not only a nuisance, it is also a vital factor in successful submarine training. Noise generated by pressure reduction in power plants on ships can lead to sound detection with devastating consequences. In addition, sound vibrations can cause structural damage to nearby pipelines and pressure vessels.

From the foregoing it is evident that a large reduction the speed is necessary to get a tolerably low noise level to reach. With the usual shut-off and throttle valves ("plug and critice valves ") is such a speed reduction only when using lower Pressure drops possible, seriously limiting the usefulness of such a construction will.

the obviously high noise level of the throttling occurs additionally the wear effect.

Conventional shut-off and throttle valves, for example, show extensive Signs of erosion on or near the valve and the throttle bore, if they are exposed to a high pressure drop. In turn, the higher the pressure drop, the more the wear and tear is increased and the shorter the service life of the Regulatory body.

According to the invention, a drastic reduction in the pressure drop can be achieved Switch off the wear and tear at each individual throttling point, especially the through cavitating fluids caused erosion. by applying a gradual Reduction method, as described below, can completely remove cavitation be avoided.

An important object or feature of the invention is to provide one Device for limiting the throttle speed by arranging a large Number of throttle cells in series. This increases the pressure drop (and speed) limited at each individual level, although the total pressure drop on the whole device can still be very high. It is more important that through the invention the "splitting" of the pressure drop even with iinder the flow rates and flow cross-sections by simply changing all the throttle cross-sections arranged in series is made possible by the same amount.

other objects or features of the invention are to provide an adjustable throttle device that requires only a small adjustment path, so that folds @ älge or @ e @ branen can be used for sealing, whereby u-The required adjusting force is considerably reduced.

Another object or feature of the invention relates to an apparatus with a large number of adjustable throttle points connected in series, which are arranged within a small space and are only light in weight erforeern and which can be economically assembled from easily available, no involved parts requiring machining techniques or tolerances, such as stenciled discs and rings.

Finally, according to the invention, there is an adjustable throttle device for fluids created in series switched throttling points for Has fluids and produce either laminar or turbulent flow patterns can, with a gradually increasing flow cross-section to compensate for a change in density of the fluid between the primary and the last throttle point.

These and many other objects, features, and advantages of the invention are based on the following description in connection with the attached Drawings can be more fully set forth and understood.

In the drawings: Fig.1 is a central vertical section showing the structure and the arrangement. of a throttle device according to the invention for pressure reduction; shows incompressible fluids; Fig. 2 is an enlarged view part of FIG. 1; 3 shows a central vertical section through a modified one Embodiment of the invention with gradually increasing flow areas for use with compressible fluids; 4 is an enlarged central sectional view through a portion of an embodiment of the invention individual modified throttle points with radial grooves to increase the flow resistance; and FIG. 5 is a central vertical section showing the structure and disorder of a Another embodiment of the invention for reducing the pressure of compressible fluids shows, with additional acting on the spindle and hydrostatic forces to be compensated Means.

The shown in Fig. 1 embodiment of the invention is as an in-line throttle device with five (or, if desired, with any larger number of) separate throttle sections formed.

Details of the sections are shown in FIG. 2, through inlet 5 Fluid entering a spindle 6 flows through a horizontal bore 7 in one of a sealing ring t3 and of a number of concentric rings or Disk 10 formed cavity @. The rings 10 are accommodated in a housing 11 and evaluate by outer pipe pieces 12 held at equal distances from one another. Between these rings there are circular projections 13, which in the embodiment the 'ig. 1 are designed as punched disks.

These disks or projections 13 are equidistant from each other Arranged on the spindle 6 separated from one another by inner pipe sections 14. This The set of projections 13 and inner pipe sections 14 are clamped together by a nut 15 and held in place while the outer set of rings 10 in the housing 11 between a shoulder 16 and the sealing ring 9 by means of a threaded fastener 17 is held.

The complete housing 11 with the rings 10 can be around the Spindal 6 are rotated, which in turn engages with thread 18 in the housing. Horizontal rotation of the housing 11 reduces (as can be better seen from FIG. 2) the throttle spacing @ by the same amount within each throttle section, reducing the amount of flowing fluid is vorringert. By resting the rings 10 on the projections 13 is rotation of the housing in the closing direction and through a sleeve 19 on the spindle 6 limited in the "opening" direction. Between the spindle 6 and the sealing ring 9 or the housing 11 suitable O-ring seals 20 are arranged to prevent the escape to prevent fluid.

The pressure reduction is brought about by the fact that the Media are forced into each by the successive rings 10 and the intermediate projection 13 formed throttle section two sharp U-shaped To carry out diversions; the final outflow of the fluid takes place through a second horizontal hole 21 and a central bore 22 in the Spindle 6.

In the position in which the adjustable throttle device (such as shown) is the most open, the distance @ is equal to the distance w and the liquid can flow through a constant flow cross-section with the general arrangement of four 90 ° deflections arranged in a row (per throttle station). Here the energy conversion (loss of speed) is carried out by @@ rt, that the fluid is forced to continuously flow through the device Change direction, creating turbulent friction. When the turbulence is also high, it is concentrated in a relatively small cross-section and Distributed over a large area formed between the circumferences d and D. will.

With a smaller throttle cross-section (smaller H / W ratio) the amount of loss generated by the change of direction is reduced. However will the input and output losses of the one. relatively coarse flow cross-section (W) in una, off; a smaller cross section (R) flowing fluid reinforced, whereby the coefficient K of the mean velocity loss amount is kept relatively high becomes regardless of @ u @ or @ / w ratio.

never total sum of the coefficient K of the amount of velocity loss can be calculated as follows: K = n (1 + R) (1.3C2 1,5) where n 'is the total number of the throttling points, R = (d / D) 2 and C = H / W ratio.

It can now be seen that for a fluid throttle device with five throttling points at C s 1 and a d / X ratio of 0.8 in the fully open state, a coefficient of the amount of velocity loss of 23 results. This is in contrast to an ordinary shut-off and throttle valve, which has a K value of around 0.8. The practical importance of the increased K-value is that the aforementioned fluid throttle device only needs 18 s to generate the speed of the liquid which would be necessary in a shut-off and throttle valve to generate an equally large pressure drop, since v² h = K 2g With a very small H / W ratio, additional friction losses along the route L can be quite high, especially if the Reynold's number is reduced to below 2000 and the flow pattern becomes laminar. Under these conditions 64 LK = NH r where the Reynolds number Q = flow rate m³ / sec; o = kinematic viscosity m² / sec; L, d, D and H in m.

For a further increase in the K value, as shown in Fig. 4, the mating surfaces of rings 110 and projections 113 interdigitated be formed with grooves 24. beer is forced aas fluidum, again its direction to change, which results in a pressure loss when it comes from an annular groove 24 is diverted to the next.

After determining K, the total flow capacity can be obtained by applying a flow coefficient @ which is the number of 3.79 liter units ("galons") of water passed through at a pressure drop of 0.07 kg / cm² (1 psi) flow through a throttle device.

Cv = 38.1 d γ To get the best possible balance to achieve the pressure drop between all throttling points, the differences must be in the density account must be taken of that in compressible liluida such as steam appear.

Since the bridge is reduced with each subsequent throttle level (which means an increased flow rate due to the lower density) you have to use the increase successive flow cross-sections to approximately the same size To obtain throttle speeds. The embodiment according to the invention shown in FIG. 3 gives an example of the solution to this requirement. @ here the fluid passes through you Inlet flange 26 into a housing 25.

The fluid is then forced through a continuous series of throttling points to happen, as described above and which is provided by projections 27 (here formed in one piece with the hollow spindle) and by concentric rings 29 (forming a part with the housing 25). By successive enlargements the diameter of both the projections 27 and the concentric rings 29 becomes a gradual increase in the flow cross-section is achieved, so that an adjustment to the density change takes place. The fluid with a lower ultimate pressure will be collected in a channel 30 and can exit through a larger outlet flange 31. between the spindle 28 and the housing 25 a valve seat 32 designed so that, if no liquid is to flow through, a pressure-tight Shutdown is enabled.

The distance H between each protrusion and the associated concentric one Ring can be changed by an external device 33 of conventional design, the for example pneumatically or electrically operated.

This device moves the spindle 28 in the axial direction an approach 34 impure lever 35. The approach 34 is sealed by a btopfbüchse 36, in order to prevent fluid from escaping from the housing 25. The latter is on Bottom closed by a flange cover 37, which forms a part with it has guide pin 38 to contribute to the precise alignment of the shaft 28. The cross-sectional area of the projection 34 is dimensioned so that the area of the spindle, which is exposed to the high pressure of the inflowing fluid is reduced. This allows a hydrostatic balance between the high inlet pressure and the lower outlet pressure acting on the entire lower cross section of the shaft 28 getting produced.

Another way to compensate for the hydrostatic effects on the spindle Forces is shown in FIG. 5. In this embodiment, the spindle 128, which is shown here with annular grooves 124, a number from Holes 139, which are arranged behind the valve seat 132 through flow chamber Connect 140 to an interior space 141 in the spindle 128. This inner space 141 is at its bottom by a widened, from a bottom cover 137 after top extending guide pin 138 closed. The one supplied through inlet 126 Fluid at a pressure that is almost as high as the inlet pressure is now through the holes 139 fed to the interior 141 at the moment in which the valve seat 132 is opened. This inlet pressure now acts on the cross-sectional area of the guide pin 138, creating an upward pressure on the spindle 128, the is as great as the combined downward forces that arise across the total outer diameter of the spindle 128 due to the various high distribute the pressures acting on the individual projections. This creates an effective pressure equalization achieved, which reduces the force required for the adjustment device, the connected to the spindle 128 by a rod 134, a yoke 135 and a lever 136 is.

line rings and projections form separate passages for the flow, interconnected by radial passages in each embodiment shown in the drawing are connected. In the examples of FIGS. 3 and 5, they are enlarged Diameter of the rings and projections, gradually enlarged passage cross-sections along the Spindle An expansion of the flow cross-sections can also by gradually changing the shapes of the rings and projections along the Spindle can be achieved either instead of or in addition to the increase in Cross-sections by increasing the diameter.

The invention has been made in connection with particular embodiments revealed, which of course are only intended to serve as an explanation, and those Compared to this, numerous changes were made in the structure and in the order of the parts can be. For example, the device shown in Fig. 3 can be designed so that the entry and exit of the fluid through a central hole in the spindle 28 (similar to FIG. 1) takes place. It is also possible to have two sets of throttling points to be arranged on a common spindle, to compensate for the on the spindle acting hydrostatic forces, the fluidum enters between these sets.

Claims (10)

Expectations 1. Adjustable throttle device for fluids, g ek e u n z e i c h n e t by an elongated hollow housing (11, 25) with a series of axially Spaced concentric protruding from the housing inwardly Rings (10, 29) by a passing through the housing and through the rings Spindle (6, 28, 128), the spindle having an equal row of axially spaced having mutually arranged projections (13, 27), which all extend outwards extend and cooperate with the corresponding rings (10, 29) of the housing (11, 25), the spindle cooperating with the housing to provide offset axial flow openings with a radially extending flow opening between them; by a device for the relative axial displacement of the housing and the spindle, and through seals between the housing and the shaft. 2. Adjustable throttle device according to claim 1, characterized in that g e k It should be noted that fluid inlet and outlet ports are located opposite one another Ends of the spindle provided, connected to the space between the housing and the spindle and arranged above and below the rows of fins and projections, respectively. 3. Adjustable throttle device according to claim 1, thereby g e k n n n z e i c h n e t that the projections and rings are circular, and that the spindle is threaded (18) into the housing for its axial adjustment intervenes. (Fig. 1) 4. Adjustable throttle device according to claim 1 or 2, in that the rows of concentric rings and Projections are circular and extend from one end of the throttle device to the opposite only have gradually larger diameters. (Fig. 1 and 5) 5. Adjustable throttle device according to one of claims 1 to 4, characterized g e k e ri n z o i c ii n e t that the spindle on its circumference as a valve element and the housing as a corresponding one disposed within the hollow housing Valve seat is formed. 6. Adjustable throttle device according to one of claims 1 to t), by noting that the housing has an inlet and an outlet flange (26, 31) has for the access of fluidum to the spaces within the housing, the flanges being above and below the rows of equidistantly arranged rings and projections are provided. 7. Adjustable throttle device for liquids according to one of the Claims 1 to 6, characterized in that an actuating device (33) with the spindle (28) is connected to its axial position together with their Series of projections (27) and thus the distance between the latter and the concentric rings (29) of the housing and the axial width of the radial flow openings to change. 8. Adjustable throttle device according to one of claims 1 to 7, characterized in that the opposing surfaces of the rings and projections having at least one set of circular grooves (24), wherein each circular groove is arranged on a protrusion so as to interfere with a similar one Groove on the opposite surface of the corresponding ring mates. 9. Adjustable throttle device according to one of claims 1 to 8, g e k e n nn z e i c h n e t by closure means for closing the housing at its lower end and through a seal cooperating with the screw spindle above the rows of projections and rings to provide hydrostatic compensation to accomplish. 10. Adjustable throttle device according to claim 9, characterized g e does not indicate that the spindle has a Has interior, which is closed at its lower end by the closure means and by his Axial adjustment range passes through, and means for establishing a fluid connection between the chamber and the cavity of the housing in the vicinity of the upper end of the rows of projections and rings are arranged. L e r s e i t e