Method for the piloting of pneumatic members, particularly in systems for cleaning industrial filters

Abstract

 The method (M) for the piloting of pneumatic members, particularly in a system (I) for cleaning industrial filters, wherein the system (I) comprises a power supply unit (T), a plurality of activation units (A₁-A_n) operatively connected to respective solenoid valves (EV₁-EV_n) for the command of pneumatic members, a single connection line (L) between the power supply unit (T) and the activation units (A₁-A_n), and wherein method comprises:
a step (106) for producing on the line (L) a voltage level (V_x), selected from a set of predefined voltage levels (V₁-V_m);
a step for maintaining the voltage level (V_x) on the line (L) for a time interval (T_y), selected from a set of predefmed time intervals (T₁-T_q);
wherein the voltage level (V_x) and the time interval (T_y) together define a univocal address (V_x, T_y) associated with one of the activation units (A_x).

Description

[0001] The present invention relates to a method for the piloting of pneumatic members, particularly in systems for cleaning industrial filters.

[0002] With reference to the industrial sector, it is common and known for some time to use filters able to retain solid particles discharged into the atmosphere as processing and manufacturing debris.

[0003] The filters are conventionally made of so-called sleeves or cartridges also of large size, achieved by using suitable calibrated-weft materials.

[0004] The filter standard maintenance requires periodical cleaning operations, conventionally performed by shaking each filtering element.

[0005] In particular, the shaking is generally achieved by suitable jets of compressed air, piloted by a plurality of respective pneumatic solenoid valves which, when opening, provide air to blow on the surfaces of each filter section, in order to release the accumulated debris.

[0006] One of the problems of the above mentioned method is the need to provide for the power supply to each solenoid valve, which requires, in the current state of the art, the repeated wiring for each individual element, with the starting point placed on a control panel, available to operators, and the arrival point at the different solenoid valves.

[0007] In order to overcome this drawback, a first solution of known type provides for the supply of each module or group of solenoid valves by means of a single bipolar line and according to a scheme in series.

[0008] In particular, the electrical current received from the first module comes directly from the control panel.

[0009] The first module, in turn, transmits the current to the next module and so on for all the modules according to a scheme in series.

[0010] Each module provides for the same number of solenoid valves and each solenoid valve of a module is connected to a corresponding solenoid valve on another module.

[0011] A second solution of known type provides for the supply of each module or group of solenoid valves by means of a single bipolar line, using a sequential piloting method.

[0012] In particular, the current coming from the control panel is received directly by the first module that, after activating in sequence all the solenoid valves of their own group, cuts power and transmits the current to the second module.

[0013] The second module, in turn, activates the solenoid valves of their own group, in sequence, to transmit the current to the next module and so on for all the modules, before repeating the cycle.

[0014] A third solution of known type provides for the supply by means of a bipolar line common to all modules or groups and serial data line, with a sequential activation scheme.

[0015] In particular, the power coming from the control panel is common to all the modules and the modules are connected together and to the control panel via a serial line.

[0016] Each module is identified by a univocal address and only one module at a time can be activated which, in turn, feeds only one valve at a time.

[0017] With reference to a fourth solution of known type, the power supply is performed by means of a multi-polar line of individual solenoid valves.

[0018] In particular, each module is constituted by an individual solenoid valve and is connected via a multi-polar line.

[0019] Each module is connected to a different pole, effectively creating a bipolar connection for each module, made on a multi-polar line.

[0020] The known solutions do have however some drawbacks.

[0021] A first drawback concerns the solution with individual wiring for each solenoid valve, with direct power supply from the control panel, and the solution with power supply of individual solenoid valve modules with a multi-polar cable.

[0022] In both cases, in fact, the drawback consists in the amount of cables needed for the connection of all the filter modules.

[0023] In particular, with reference to the individual wiring a considerable amount of coils of cable is required for the connection of all the solenoid valves.

[0024] With reference to the solution with multi-polar cable, the large number of cables used is further increased due to the use of a multi-polar cable, with consequent practical limits in the cable maximum section and, therefore, with effects of degradation in power supply over long distances, between the control panel and the modules.

[0025] A second drawback concerning the first solution of known type is the fact that all the solenoid valves of each module are activated simultaneously during the filter cleaning phase.

[0026] Therefore, the resulting simultaneous power supply of the corresponding pneumatic members involves the ejection of air on filter sections that are not sequential to one another, resulting in less efficient removal of debris and higher air consumption.

[0027] A further drawback related to the second solution of known type is due to the fact that, necessarily, each group or module can be activated only after activating all the previous groups or modules.

[0028] Another drawback related to the third solution of known type concerns the excessive complexity of the system, which can be only accepted for large filters. This solution, therefore, is not suitable for filters with one or a few modules and a reduced number of solenoid valves.

[0029] The main aim of the present invention is to devise a method for the piloting of pneumatic members, particularly in systems for cleaning industrial filters, allowing the individual activation of each in individual solenoid valve via a single activation unit, using at the same time a simplified wiring.

[0030] Another object of the present invention is to devise a method for the piloting of pneumatic members, particularly in systems for cleaning industrial filters, which can overcome the above mentioned drawbacks of prior art in the ambit of a simple, rational, easy and effective to use as well as affordable solution.

[0031] The above mentioned objects are achieved by the present method for the piloting of pneumatic members, particularly in systems for cleaning industrial filters, according to claim 1.

[0032] Other characteristics and advantages of the present invention will become better evident from the description of a preferred, but not exclusive, embodiment of a method for the piloting of pneumatic members, particularly in systems for cleaning industrial filters, illustrated by way of an indicative, but non limitative example in the accompanying drawings in which:

Figure 1 is a general block diagram of a system provided with n activation units, operated by the method according to the invention;

Figure 2 is a flow diagram that illustrates the operation of a control unit of the system according to Figure 1;

Figure 3 is a graph illustrating the distribution of the addresses of each single activation unit, in the plan of the voltage levels and timing, with reference to the system according to Figure 1;

Figure 4 is a flow diagram illustrating the operation of each single activation unit.

[0033] With particular reference to Figure 2, globally indicated with M is a method for the individual piloting of solenoid valves for the command of pneumatic members, which can be used on a system I for the cleaning of sleeve and cartridge filters.

[0034] In particular, the system I according to the invention is used for the cleaning of sleeve and cartridge filters normally used for the purification of air flows in industrial processes.

[0035] The piloted pneumatic members and related filters are not shown in the figures because of the conventional type.

[0036] The system I comprises a power supply unit T that is connected to and which supplies, through a single line L, a series of n single activation units, numbered from A₁ to An.

[0037] In particular, all the activation units from A₁ to A_n are connected in parallel by means of the same line L.

[0038] Each activation unit A₁-A_n comprises a respective solenoid valve EV₁-EV_n.

[0039] The system I also comprises a control unit C operatively connected to the power supply unit T and able to control the power supply unit T to pilot the single activation units from A₁ to An and, therefore, the respective solenoid valves EV₁-EV_n according to a predefined scheme.

[0040] In particular, the method M can be implemented using a suitable software program to control the power supply unit T, integrated within the control unit C. With reference to a preferred embodiment and to a generic set of solenoid valves, the control unit C is able to activate the solenoid valves EV₁-EV_n according to the method M illustrated in Figures 2, 3 and 4 and described below.

[0041] First, the method provides for the switching on of the power supply unit T (step 100).

[0042] Subsequently, the voltage output directed to the single activation units A₁-A_n is disabled by means of the line L (step 101). In this configuration, the power supply voltage is therefore equal to zero Volt.

[0043] Afterwards, a reading is made of the parameters entered in the control unit C which controls the power supply unit T (step 102).

[0044] According to the operating parameters acquired, the power supply unit T starts a sequence of association of a new address of a single activation unit A_x (step 111) or, alternatively, it produces a pause command, bringing the line L to a predetermined pause voltage value V1 (step 103).

[0045] Preferably, the pause voltage value V1 is equal to 8 Volts.

[0046] After activating the pause command, none of the solenoid valves EV₁-EV_n will be activated and the voltage of line L will be maintained at a value of 8 Volts for a predefined pause time interval (step 104).

[0047] Once the pause time interval is finished, the power supply unit T produces an addressing command (step 105) and, in particular, varies the voltage of line L from the pause voltage value V1, preferably equal to 8 Volts, to an addressing voltage value V_i, preferably equal to 20 Volts.

[0048] Once the production of the addressing command is finished, the power supply unit T produces an address univocally associated with a single activation unit A_x, bringing the voltage on line L to a voltage level V_x with a value between the pause voltage value V1, preferably equal to 8 Volts, and the addressing voltage value V_i, preferably equal to 20 Volts (step 106).

[0049] Furthermore, the power supply unit T maintains such voltage level V_x for a predefined time interval T_y (step 107).

[0050] Advantageously, the pair of parameters consisting of the voltage level V_x applied to line L and the time interval T_y for maintaining such voltage define a univocal address of the activation unit A_x.

[0051] By way of example, in the graph of Figure 3 are illustrated possible addressing of the activation units A₁-A_n, where each univocal address is defined by a respective pair of sizes consisting of:

• a voltage value V_x, belonging to the range of voltage values V₁-V_m;
• a time interval T_y, with y from 1 to 4.

[0052] Preferably, the voltage V_m is equal to the addressing voltage V_i.

[0053] The use of different ranges of voltage values V₁-V_m cannot however be ruled out.

[0054] In this regard, it is also stated that the number and amplitude of time intervals T1, T2, T3 and T4 shown in Figure 3 are only to be considered as a simple descriptive example.

[0055] Different embodiments in which the time intervals used are different in number and amplitude cannot however be ruled out.

[0056] Once the time interval T_y is finished, the power supply unit T produces a work command, namely for the activation of the solenoid valve EVx, bringing the voltage applied to the line to a work voltage value V3, preferably equal to 24 Volts (step 108).

[0057] This voltage value equal to 24 Volts is maintained for a predefined work time interval T_L, set by the control unit C (step 109).

[0058] This last step corresponds to the work phase of the pneumatic members associated with the activated solenoid valve EVx.

[0059] In particular, the valve EVx operates the corresponding pneumatic member, which ejects a jet of compressed air on a corresponding section of a filter, cleaning it from the deposited impurities.

[0060] Once this work phase has been completed, a check is made whether all the solenoid valves EV₁-EV_N have been activated, or whether all the addresses were produced corresponding to the single activation units A₁-A_n and the relative work command (step 110).

[0061] Otherwise, the control unit C repeats all the steps in a cyclic manner starting from the production of the pause command (step 103) to the activation of all solenoid valves EV₁-EV_n, thereby completing the sequence stored within the control unit C.

[0062] When all the solenoid valves EV₁-EV_n have been activated, then the control unit C checks its internal parameters (step 102), repeating the sequence or not depending on the status of the system and the set operating parameters.

[0063] Every single activation unit A₁-A_n controlled by a respective solenoid valve EV₁-EV_n contains internally the value of the address univocally assigned to it. The procedure for assigning the address to each single activation unit A₁-A_n, and the storage of the address inside it, can be performed by the control unit C by connecting to line L only one new activation unit at a time.

[0064] Alternatively, the assignment of the address to each single activation unit A₁-A_n can be carried out in advance during the production phase.

[0065] The connection diagram is the same as in Figure 1 but with only one activation unit A_x connected.

[0066] In this case the control unit C, after bringing the voltage of line L to the value of 0 Volt, will produce the address storage command (step 111).

[0067] Thereafter, the control unit C produces the address by applying the relative voltage value V_x for a time equal to an associated time interval T_y (steps 112 and 113).

[0068] Subsequently, the control unit C produces the work command and proceeds as described previously (steps 108, 109 and 110), in order to allow a check by an operator of the correct storage of the address.

[0069] With reference to the operation of each single activation unit A_x, shown in detail in Figure 4, after the switching on (step 200), that is after the power supply unit T has brought the line voltage value from 0V to one of the operating values or to the pause value, the outputs are deactivated (step 201) and the level of power supply voltage, namely the level of line L, is measured (step 202). Subsequently, from the memory of the activation unit A_x is read the value of the relative address (step 203), and it is checked whether the power supply unit T has activated the address storage command in the memory of the unit (step 204).

[0070] In case of a positive outcome, the value of voltage applied to line L and the relative time interval of application are detected, producing the corresponding address (step 207), whose value is stored in the internal memory of the activation unit itself (step 208).

[0071] Subsequently, the operation of the activation unit A_x continues as if it were performing the steps following the one of normal addressing.

[0072] In case of a negative outcome (step 204), the activation unit A_x checks whether the command produced on line L is the addressing one (step 205).

[0073] In case of a negative outcome, the activation unit A_x repeats the check of the voltage value of line L, waiting for a valid command.

[0074] Otherwise, in case of a positive outcome and of the addressing command of the unit being recognized, the unit activation A_x acquires the voltage values V_x and the time interval T_y associated with the address sent by the power supply unit T and compares them with the value read in the memory (step 207), validating the address or not.

[0075] In the second case, the method resumes from the check of the presence of a valid command on line L (step 204).

[0076] On the contrary, in the first case, after the validation of the address present on line L, the check is carried out of the work command (step 210), which must correspond to the voltage value V3 sent from the power supply unit T, and must last throughout the work time interval T_L required upon activation of the checked solenoid valve and the associated pneumatic members, in order to produce the jet of air necessary for cleaning the designated filter portion.

[0077] Therefore, if the work command is recognized (step 210) the output of the activation unit A_x (block 212) is activated and, therefore, of the solenoid valve EVx, and is kept active for the entire time interval T_L at the work voltage value V3 (24 volts).

[0078] When the value of line L returns to a lower value than the work one, the output is deactivated and the work phase ends (step 211).

[0079] At this point, the activation unit A_x returns to the point of waiting for a new addressing command (step 205).

[0080] The value of 0 volt on line L deactivates all the activation units A₁-A_n, causing them to switch off.

[0081] A voltage value equal to or higher than the pause level (8 Volts) causes the switching on and the execution of the operating cycle from the beginning (step 200), synchronizing all units.

[0082] The application of the pause voltage value after the work command (step 103 of Figure 2) maintains the activation units A₁-A_n in the waiting phase with the output deactivated (step 205).

[0083] It has in practice been found how the described invention achieves the proposed objects.

Claims

1. Method (M) for the piloting of pneumatic members, particularly in a system (I) for cleaning industrial filters, wherein said system (I) comprises at least a power supply unit (T), a plurality of activation units (A₁-A_n) operatively connected to respective solenoid valves (EV₁-EV_n) for the command of pneumatic members, a single connection line (L) between said power supply unit (T) and said activation units (A₁-A_n), characterized by the fact that said method comprises:

at least a step (106) for producing on said line (L) a voltage level (V_x), selected from a set of predefined voltage levels (V₁-V_m);

at least a step for maintaining said voltage level (V_x) on said line (L) for a time interval (T_y), selected from a set of predefined time intervals (T₁-T_q);

wherein said voltage level (V_x) and said time interval (T_y) together define a univocal address (V_x, T_y) associated with one of said activation units (A_x).

2. Method (M) according to claim 1, characterized by the fact that it comprises at least a step (108) of producing a work command, wherein the voltage on said line (L) is equal to a work voltage value (V3), and wherein said work voltage (V3) is suitable for activating a solenoid valve (EV_x) operatively connected to said activation unit (A_x) associated with said univocal address (V_x, T_y).

3. Method (M) according to one or more of the preceding claims, characterized by the fact that said step of producing a voltage level (V_x), said step of maintaining said voltage level (V_x) on said line (L) for a time interval (T_y) and said step of producing the work command are repeated iteratively, for the activation of at least one part of said activation units (A₁-A_n) according to a preestablished scheme.

4. Method (M) according to one or more of the preceding claims, characterized by the fact that said work voltage value (V3) is maintained for a predefined work time interval (T_L).

5. Method (M) according to one or more of the preceding claims, characterized by the fact that it comprises at least a step (101) of disabling the output voltage of said power supply unit (T), before said step of producing said voltage level (V_x).

6. Method (M) according to one or more of the preceding claims, characterized by the fact that it comprises the step (103) of producing a pause command, wherein said output voltage of the power supply unit (T) is equal to a predefined pause voltage value (V1).

7. Method (M) according to one or more of the preceding claims, characterized by the fact that said pause voltage value (V1) is maintained for a predefined pause time interval.

8. Method (M) according to one or more of the preceding claims, characterized by the fact that it comprises at least a step (105) of producing an addressing command, wherein said output voltage of the power supply unit (T) is equal to a predefined addressing voltage value (V_i).

9. Method (M) according to one or more of the preceding claims, characterized by the fact that said voltage level (V_x) is between said pause voltage value (V1) and said addressing voltage value (V_i).

10. Method (M) according to one or more of the preceding claims, characterized by the fact that it comprises at least a step (110) of checking if all the univocal addresses (V_x, T_y) corresponding to the single activation units (A₁-A_n) and the relative work command have been produced.

11. Method (M) according to one or more of the preceding claims, characterized by the fact that it comprises at least a sequence of association of a new address (V_x, T_y) with one of said activation units (A₁-A_n).

12. Method (M) according to one or more of the preceding claims, characterized by the fact that said sequence of association comprises:

- at least a step (111) of producing an address storage command (step 111);

- at least a step (112) of producing a predefined voltage value (V_x);

- at least a step of maintaining said voltage value (V_x) for a time equal to a predefined time interval (T_y).

13. Method (M) according to one or more of the preceding claims, characterized by the fact that it comprises a step (202) of measuring the voltage level on said line (L) by means of at least one of said activation units (A_x-A_n).

14. Method (M) according to one or more of the preceding claims, characterized by the fact that it comprises at least a step (204, 205, 210) of checking by at least one of said activation units (A_x-A_n) if at least one of said storage command, said addressing command and said work command is present or not on said line (L).

15. System (I) for the piloting of pneumatic members, particularly for cleaning industrial filters, comprising at least a power supply unit (T), a plurality of activation units (A₁-A_n) operatively connected to respective solenoid valves (EV₁-EV_n) for the command of pneumatic members, and a single connection line (L) between said power supply unit (T) and said activation units (A₁-A_n), characterized by the fact that said activation units (A₁-A_n) are univocally associated with respective univocal addresses (V_x, T_y), wherein each univocal address (V_x, T_y) comprises:

at least a voltage level (V_x), produced by means of said power supply unit (T) and selected from a set of predefined voltage levels (V₁-V_m);

at least a time interval (T_y) for maintaining said voltage level (V_x) on said line (L), selected from a set of predefined time intervals (T₁-T_q).

Drawing