EP1114275A1

EP1114275A1 - Device for minimising pressure drop in a compressed air circuit

Info

Publication number: EP1114275A1
Application number: EP99942975A
Authority: EP
Inventors: Jean-Jacques Lorieul
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-09-15
Filing date: 1999-09-15
Publication date: 2001-07-11
Also published as: WO2000016003A1; CA2343015A1; FR2783288A1; FR2783288B1

Abstract

The invention concerns a device for regulating pressure in a compressed air circuit comprising a compressor (42) supplying compressed air, a tank (42) for storing and regulating compressed air downstream of the compressor, a looped grid-type system (43) with specific dimensions comprising at least a pneumatic tool or machine connected to the grid-type system by a hose (23). The invention is characterised in that it comprises at least an element (10) regenerating the compressed air velocity mounted on the looped grid-type system (43).

Description

Pressure drop minimization device in a compressed air circuit.

The present invention relates to a device for regulating pressure in a compressed air circuit for an industrial installation used, for example, to connect pneumatic tools or machines.

It is known in the prior art compressed air circuits used for the distribution of energy in an industrial installation comprising, a compressor, a storage and regulation tank and a looped mesh network. The user connects pneumatic tools or machines to the network via hoses. As a general rule, the pressure at the outlet of the compressor is close to its maximum pressure, for example 8 bars and the flow rate is 1000 m ³ / h. The pneumatic tools usually used with this type of network are designed for optimal operation under a pressure of 7 bars. However, it can be seen that the pressure on the network is irregular due to pressure losses and that, in particular in certain places, it is only 6 bars. This pressure difference is essentially due to phenomena of air friction in the pipes and to pressure losses due to inevitable leaks on the distribution circuit. In addition, the compressor is protected so as not to exceed its maximum pressure, for example 8 bars and is generally reset with a pressure below 1 bar. Thus near the walls of the pipeline, the speed is only 7 to 8 m / s for a speed at the center of 12 m / s. This difference in pressure has two consequences, on the one hand, it results in a waste of energy, since the compressor provides a pressure of about 8 bars at the inlet of the network and that 6 bars are only available to operate the tools or machines. On the other hand, the pneumatic tools or machines being designed to operate at 7 bars, these are less efficient when operating at 6 bars (about 30% less efficiency).

The object of the present invention is to provide a device making it possible to have an almost identical air pressure in a looped mesh network. compressed air, thus optimally using the characteristics of the compressor and overcoming the drawbacks of the prior art.

This object is achieved by the fact that the compressed air circuit comprises a compressor supplying the compressed air, a reservoir for storing and regulating the compressed air downstream of the compressor, a looped mesh network of determined dimensions comprising at least a connection outlet for a pneumatic tool or machine connected to the looped mesh network by a hose, characterized in that it comprises at least one element for regenerating the speed and pressure of the compressed air mounted on the looped mesh network. According to another characteristic of the invention, the speed regenerating element comprises a capacity of cylindrical shape whose ends constituting the bottoms are curved, and of determined dimensions, an inlet pipe and an outlet pipe of the same determined diameter, the inlet and outlet pipes are connected to the capacity and make a determined angle between them, the cylinder forming the capacity is either of circular section, or of polygonal section.

According to another characteristic of the invention, the connection point of the inlet pipe is located in the lower third of the capacity and the connection point of the outlet pipe is located in the upper third of the capacity so that that the distance between the axes of symmetry of the pipes is close to half the value of the height of the capacity and that their axes of symmetry are substantially perpendicular to the axis of symmetry of the capacity.

According to another characteristic of the invention, the dimensions of the capacity, and the diameter of the inlet and outlet pipes are determined so that if A is a determined unit of measurement, and less than 90 mm, the diameter of the pipes is close to A, the diameter of the capacity is close to twice A, and the height of the capacity is close to four times A, and if A is greater than 90 mm, the diameter of the capacity is close to four thirds of A, and the height of the capacity is close to three times A, A being determined as a function of the characteristics of the compressor supplying the looped mesh network, and of the desired pressure at the outlet of the mesh network. According to another characteristic of the invention, the angle between the inlet pipe and the outlet pipe is chosen between 85 and 95 °.

According to another characteristic of the invention, the capacity is equipped with a circular deflector with fins, mounted perpendicular to the axis of symmetry of the capacity, the center of this deflector being provided with a circular opening and authorizing a preferential channel effect.

According to another characteristic of the invention, the capacity is equipped with a purge solenoid valve, and / or a safety valve, and / or a control manometer and / or a hygrometer. According to another characteristic of the invention, the looped network of the compressed air circuit is rectangular in shape and comprises at each of the angles of the rectangle a speed and pressure regenerating element according to the invention.

According to another characteristic of the invention, for a pressure at the outlet of the compressor of approximately 8 bars and a flow rate of approximately 1000 m ³ / h, the mesh network whose developed length is at most 400 m long , being mounted with a slope of about 1% where the lowest part of the network, is downstream of the circuit and A is preferentially chosen in this case between 90 and

1 10 mm. According to another characteristic of the invention, in the above case, the secondary compressed air pipes of the network not connected to an air speed regenerating element have a minimum diameter between 55 and

65 mm.

According to another particularity, the connections of pneumatic tools or machines have a determined diameter chosen between 25 and 35 MM according to the specific consumptions of the tools or machines.

According to another characteristic of the invention, the circuit comprises, downstream of the storage and regulation tank, and upstream of the network, means for filtering and dehumidifying the air. According to another characteristic of the invention, its air filtering and dehumidification means comprise from upstream to downstream, a prefilter 5 μ mechanical filter, 1 μ mechanical dust filter, air dryer, 0.01 μ filter and 0.003 μ filter.

Other features and advantages of the present invention will appear more clearly on reading the description below made with reference to the accompanying drawings in which:

FIG. 1 represents a detailed view of the air speed regenerating element,

FIGS. 2A and 2B represent a top view and a sectional view of the fin deflector, FIG. 3 represents a schematic view of a compressed air circuit fitted with the device according to the invention,

- Figure 4 shows a schematic view of the air filtering and dehumidification means.

Figure 1 shows a detail view of the air speed regenerator element. This speed regenerating element (10) comprises a capacity (11), for example, of cylindrical shape, an inlet pipe (20) in the lower half of the capacity and an outlet pipe (21) in the upper half of the capacity making a determined angle between them. The ends, forming the bottoms of the container (11), are curved and the cross section is circular or polygonal. The two pipes (20,21) are, for example, two identical tubes of determined diameter. The tank (11) is equipped, for example, with a safety valve (12), and / or a pressure gauge (16) indicating the pressure existing inside the tank and / or a purge ( 13) located in the lower part of the capacity in order to evacuate the water (14) possibly accumulated in the capacity and / or a hygrometer (17). The pipes (20,21) are arranged such that, for example, the angle between the two pipes (20,21) is chosen between 85 and 95 °, and that, for example, the axes of symmetry of the two pipes (20 , 21) inlet and outlet are substantially perpendicular to the axis of symmetry of the capacity. In a particular configuration, the distance between the axes of symmetry of the inlet and outlet pipes (21, 20) is substantially equal to half of value of the height of the capacity (10). There is, preferably, a mathematical relationship between the value of the diameter of the inlet and outlet pipes (21, 20), the value of the diameter of the capacity (11) and the value of the height of the capacity (11 ). If A is a determined value, then if A is less than 90 mm, A corresponds substantially to the diameter of the inlet and outlet pipes (21, 20), twice A corresponds substantially to the diameter of the capacity (11), and 4 times A corresponds substantially to the height of the capacity (11). If A is greater than 90 mm, A corresponds substantially to the diameter of the inlet and outlet pipes (21, 20), 4/3 times A corresponds substantially to the diameter of the capacity (11), and 3 times A corresponds substantially to the height of the capacity (11). A is determined according to the characteristics (pressure and air flow) of the compressor (41 fig. 3) used in the circuit, and the minimum pressure desired by the user in the network (43 fig. 3) meshed. For example, for a compressor delivering a maximum pressure of approximately 8 bars and a flow rate of approximately 1000 m ³ / h and a minimum desired pressure in the network (43 fig. 3) with a mesh of approximately 7.5 bars , the value of A is substantially equal to 100 mm if the developed length of the mesh network is at most 400 m long. The operating principle of the speed regenerator element is as follows. When the compressed air enters with an initial speed given into the capacity (11) by the inlet pipe (20), due to the particular arrangement of the capacity (11) and the inlet pipe (20), a cyclonic or swirling movement (15) is created in the capacity which has the consequence of increasing the initial speed of the compressed air and of minimizing the previously accumulated effects of pressure drop. Thus, when the compressed air is evacuated by the outlet pipe (21), it has a higher outlet speed, which counterbalances the negative effects stated above in the network (43 fig. 3) meshed with the circuit d 'air. The efficiency of the capacity (11) can be improved by introducing, for example, into the capacity (11) a fin deflector (30). The fin deflector (30) is mounted perpendicular to the axis of symmetry of the capacity (11). The fixing (10) on the vertical internal walls is ensured by cleats (32) between which the tabs (34) are housed. Fig. 2A) formed on at least two fins (33a, 33b fig. 2A) diametrically opposite the deflector (30). The deflector (30) also comprises in its center a circular bore in which is housed, for example, a piece of tube (31) forming a channel. When the compressed air enters the tank (1 1) equipped with the deflector (30) with fins, the tube (31) creates a channel effect which accelerates the speed of the compressed air. There is therefore obtained a regeneration of the average speed of the fluid in the outlet pipe (21) and a minimization of the accumulated losses.

The connection of pneumatic tools or machines is illustrated as an example in FIG. 1 on the outlet pipe (21). A supply line (22) is mounted, in the example, on the capacity outlet pipe (21) (1 1). The end of the supply pipe (22) is extended by a valve (24) to which is connected the hose (23) of the pneumatic tool or machine to be connected. Figures 2A and 2B show a top view and a sectional view of the fin deflector. As described above, the deflector with fins (30) is circular in shape, it has in its center a circular bore in which is housed a piece of tube (31) on which the fins (33) are mounted. The fins (33) are separated by regular interstices, oriented according to a helix and the end of at least two diametrically opposite fins (33a, 33b) have a tab (34) intended to be housed in the cleats (32 fig. 1) of the internal surface of the tank (1 1 fig. 1), when mounting the deflector (30). An alternative embodiment of the fin deflector consists in eliminating the end of the tube (31) by joining the fins (33) by means of lugs (35). For this variant, the deflector (30) is produced, for example, in a sheet metal plate from which the fins (33) are cut so that a portion of material remains between each fin (33) to form the legs (35 ). Then the fins (33) thus formed are oriented in a helix. FIG. 3 represents a schematic view of a compressed air circuit equipped with the device according to the invention. The compressed air circuit comprises from upstream to downstream, a compressor (41) which delivers the compressed air in the circuit, at a determined pressure and flow, a storage and regulation tank (42), and a mesh network (40) of determined dimensions. According to the invention, the mesh network (40) is equipped with at least one speed regenerating element (10). The shape of the mesh network (40) is, for example, a rectangle. In this particular configuration, the speed regenerating elements (10) are placed at the right angles of the rectangle. The mesh network (40) is, for example, mounted with a determined slope of inclination so that the lower part of the network is located downstream thereof. For example, for a compressor (41) delivering compressed air at a maximum pressure, for example, of approximately 8 bars for a flow rate of approximately 1000 m ³ / h and a rectangular mesh network (40) of approximately 400 m long, by choosing a slope of 1%, and by equipping the network (40) meshed with 4 speed regenerating elements (10) placed at the corners of the rectangle, the user obtains reduced pressure on the network (40) maximum 10%. On an experimental basis, this pressure has been measured and is of the order of 7.4 to 7.5 bars. In this particular configuration, the value of A is between 90 and 110 mm for the given flow rate, and the secondary pipes (43) forming the meshes of the network have a minimum diameter between 55 and 65 mm.

The compressed air circuit can also be equipped with means (50) for filtering and dehumidifying air. These means (50) are located downstream of the storage tank (42) and upstream of the mesh network (43). These means (50 fig. 4) include, from upstream to downstream, a mechanical filter (52) at 5 μ, a dust filter (53) of 1 μ, an air dryer (56) which condenses the humidity , a filter (54) at 0.01 μ and a filter (55) at 0.003 μ. Each means (52-56) is secured by valves (57) and each filter is provided with a drain (51). This combination of means improves the quality of the compressed air distributed in the circuit, and contributes to increasing the life of the equipment installed on the network.

The device according to the invention allows greater regularity of the working pressure of pneumatic tools or machines and less pressure fluctuation by regenerating the average speed of the compressed air. in the pipes. When the machines connected to the network according to the invention are injection presses for plastic parts, the injection molds close faster, the parts are ejected faster and the quality of molding is better. The production rate is therefore higher, and the quality of this production is better.

Furthermore, to produce the same operating pressure of 7.5 bars, it is possible to use a compressor with a lower power while saving on the order of 35 KWH on the power of the compressor, which has significant consequences. on the consumption of electrical energy for the desired pressure.

It is clear that other modifications within the reach of those skilled in the art are within the scope of the invention.

Claims

1. Device for regulating pressure in a compressed air circuit comprising a compressor (42) supplying the compressed air, a reservoir (42) for storing and regulating the compressed air downstream of the compressor, a network (43 ) looped mesh of determined dimensions comprising at least one pneumatic tool or machine connected to the network (43) meshed by a hose (23), characterized in that it comprises at least one element (10) regenerating speed and pressure of the compressed air mounted on the network (43) looped mesh.

2. A pressure regulation device in a compressed air circuit according to claim 1, characterized in that the speed regenerator element (10) comprises a capacity (11) of cylindrical shape whose ends constituting the bottoms are curved and of determined dimensions, an inlet pipe (20) and an outlet pipe (21) of the same determined diameter, the inlet and outlet pipes being connected to the capacitor and making a determined angle between them, the cylinder forming the capacity (11) is either of circular section, or of polygonal section.

3. Device for regulating pressure in a compressed air circuit according to claim 2, characterized in that the connection point of the inlet pipe (20) is located in the lower third of the capacity (11) and the connection point of the outlet pipe (21) is located in the upper third of the capacity (11) so that the distance between the axes of symmetry of the pipes is close to half the value of the height of the capacity (11) and that their axes of symmetry are substantially perpendicular to the axis of symmetry of the capacity (11).

4. Device for regulating pressure in a compressed air circuit according to claim 2 or 3, characterized in that the dimensions of the capacity (11), and the diameter of the inlet and outlet pipes (20,21) are determined so that if A is a determined unit of measurement, and less than 90 mm, the diameter of the pipes (20, 21) is close to A, the diameter of the capacity (11) is close to twice A, and the height of the capacity (11) is close to four times A, and if A is greater than 90 mm, the diameter of the capacity (11) is close to four thirds of A, and the height of the capacity (11) is close to three times A, A being determined as a function of the characteristics of the compressor (41) supplying the looped mesh network, and of the desired pressure at the outlet of the mesh network (40).

5. Device for regulating pressure in a compressed air circuit according to one of claims 2 to 4, characterized in that the angle between the inlet pipe (20) and the outlet pipe (21) is chosen between 85 and 95 °.

6. Device for regulating pressure in a compressed air circuit according to one of claims 2 to 5, characterized in that the capacity (11) is equipped with a circular-shaped deflector with fins, mounted perpendicular to the axis of symmetry of the capacity, the center of this deflector being provided with an opening of circular shape and allowing a preferential channel effect.

7. Device for regulating pressure in a compressed air circuit according to one of claims 2 to 6, characterized in that the capacity (11) is equipped with a solenoid valve (13) for purging, and / or a safety valve (12), and / or a pressure gauge (16) and / or a hygrometer (17).

8. Device for regulating pressure in a compressed air circuit according to one of claims 1 to 7, characterized in that the looped network (40) of the compressed air circuit is rectangular in shape and each has angles of the rectangle an element (10) for regenerating speed and pressure.

9. Device for regulating pressure in a compressed air circuit according to one of claims 1 to 8, characterized in that for a pressure at the outlet of the compressor of approximately 8 bars and a flow rate of approximately 1000 m ³ / h, and a looped mesh network (40) whose developed length is at most 400m long, this being mounted with a slope of approximately 1% where the lowest part of the network is downstream of the circuit and A is preferably chosen in this case between 90 and 110 mm.

10. Device for regulating pressure in a compressed air circuit according to claim 9, characterized in that the secondary compressed air pipes (43) of the network (40) looped mesh not connected to a air speed regenerating element have a minimum diameter between 55 and 65 mm, the connections of pneumatic tools or machines then having a determined diameter chosen between 25 and 35 mm according to the specific consumption of the tools or machines.

11. Device for regulating pressure in a compressed air circuit according to one of claims 1 to 10, characterized in that the circuit comprises, downstream of the storage and regulation tank (42) and upstream of the network ( 40) looped mesh, means (50) for air filtration and dehumidification.

12. Device for regulating pressure in a compressed air circuit according to claim 11, characterized in that the means (50) for filtering and dehumidifying the air comprise, from upstream to downstream, a prefilter (52) mechanical of 5 μ, a filter (53) of mechanical dust of 1 μ, an air dryer (56), a filter (54) at 0.01 μ and a filter (55) at 0.003 μ.