DE4326884A1 - Volume-flow regulator (controller, governor) for pneumatic conveyance of solid matter - Google Patents

Abstract

Overpressure conveying systems transport solid matter by expansion of compressed air. For reasons of operational reliability, a high flow rate is frequently employed, which has the result that the conveying time, the pipeline wear and the energy consumption are unnecessarily high. The invention relates to a device which, without external energy, creates a closed-loop control circuit which optimally counteracts the abovementioned negative factors. The volume-flow regulator (1) exhibits, with its oversized working piston, an essential feature. Through the pressure regulator (2) with secondary relief, a constant pressure (e.g. 1.5 bar) is transmitted onto one working-piston area, which moves the volume-flow regulator into the normal "open" position and releases a maximum flow of solid matter. If the quantity of transporting gas, regulated in quantity by a valve (3), allows approximately 1.8 bar to act on the other piston area via a filter (4), the volume-flow regulator moves into the "closed" direction as a result of the blowing-off pressure regulator (2) and thus reduces the supply of solid matter until an equilibrium is established. The volume-flow regulator can optimise any kind of solid matter conveyance and is used on all movable and fixed pressure conveying vessels. <IMAGE>

Description

The invention relates to a valve that without interruption a pneumatic conveying process is able to Transport pressure and the loading of the delivery lines optimal to regulate.

In known conveyor systems, compressed air is used to make them powdery or granular debris from pressure vessels through pipe lines to a destination. For the sake of Stagnation of the funding flow (blockages) Flow rate kept high. Disadvantages are long shorter delivery times due to the high flow rate increased wear in the pipes and the need for large amounts of production gas. When reducing the amount of feed gas and the resulting lower flow velocity it often leads to pulsating transport pressure behavior and Lich also to fluctuating flow rates. At Such uneasy subsidies locally block pipes  due to overloaded goods. The result is a system failure tion, which is not uncommon with disassembly of the pipeline part pieces is connected.

A device, fundamentally different but with a similar one Control characteristic like that of the volume flow controller is in the patent application 19 12 733 of the German Patent Office known. Here is over with the help of elastic membranes a lever system a closure member between a konventio nell under pressure vessel to be emptied and one for it additionally installed collecting vessel controlled so that at increasing delivery pressure the closure member through the mem branches controlled against a fixed, constant opening force until the constant opening force again greater than the closing force generated by the delivery pressure is. This described differential pressure control is in the Invention "Volume flow controller for pneumatic solids change ". Otherwise, all properties, such as e.g. B. Installation situation and mechanical functions, basic different.

Object of the invention "Volume flow controller for pneumatic Solid matter delivery "is to provide a device which without additional fittings as valve fittings in each Conveying line behind pressure conveying out above and below dergefäß and behind silo vehicles that ent with gas pressure be emptied, as a volume flow controller at the start of delivery stretch is installed.

This object can be achieved according to the invention in pneumatic pressure conveying systems in such a way that a valve according to FIG. 1 with a control cylinder which has oversized piston surfaces is mounted directly into the outlet behind any type of pressure vessel in the delivery line. On the piston surface to be acted upon by a constant pressure is initiated via a pneumatic pressure control valve with secondary discharge. This constant pressure is slightly less than the maximum transport pressure. As can be seen in FIG. 5, the piston surface to be acted upon by "to" is permanently connected to the transport gas line and thus to the transport pressure.

A special feature of Fig. 1 is the oversized control cylinder. At normal delivery pressure or during delivery breaks, the angled control piston is always fully open. This is due to the fact that the closing force, caused by the transport pressure on the control piston is always less than the opening force, caused by the constant pressure on the control piston as well as the force acting on the control piston from the port pressure. If the transport pressure increases more than permitted, the closing force increases compared to the opening force, the pressure regulating valve for "open" relieves the rising secondary pressure and the beveled control piston is pressed by the control piston in the "closed" direction until the opening force equals the closing force is. The quantity of material conveyed is thus reduced by narrowing the line cross-section ( FIGS. 2 and 3 show closed positions of 50 to 90%). The transport gas can relax because less material to be conveyed enters the delivery line, and accordingly the closing force is reduced, the control piston pulls the slanted control piston "on" and the quantity of material to be conveyed increases again.
Rough calculation example:

counter: control piston diameter d = 100 mm
Control piston diameter D = 400 mm
Piston rod diameter negligibly small
Max. Resistance through friction of the regulating and control piston, e.g. B. F _w = 1000 N
Pressure regulator setting for "Open": P₁ = 11.7 bar
Transport pressure max .: P₂ = 2.0 bar
Opening force = d² × 0.785 × P₂ + D² × 0.785 × P₁
= 10² × 0.785 × 20 = 40² × 0.785 × 17
= 1570 N + 21 350 N
= 22 920 N.
The required closing force must be <22 920 N.
Closing force = D² × 0.785 × P₂ - F _w
= 40² × 0.785 × 20 - 1000 N
24 120 N

The closing force at 2 bar transport pressure is 24 120 N.

Result: When the transport pressure increases to approximately 2 bar, the control piston begins to close. If the transport pressure drops below 1.8 bar, the control piston stops and opens again when the pressure drops further.
Additional special features of Fig. 1:

• 1) The aerodynamic solids control gap at diameter The delivery line is equal to the control piston in that the slope on the control piston (angle β) always the Half of the housing angle (angle α). For example β = 45 ° and consequently α = 90 ° or β = 25 ° and therefore α = 50 °.  
• 2) With additional switching of pneumatic valves ( Fig. 4) the volume flow controller can also be used as a shut-off valve.
• 3) Due to the adjustable, pneumatic actuation on one side only struck stop cylinder at the free end of the controller it possible to adjust the stroke of the control piston z. B. up to 50% to limit. The resistance of the stop cylinder can e.g. B. be designed so that at a constant pressure of 6 bar a force is generated that is in addition to the closing power of the control cylinder to a minimum transport printing of z. B. 1.4 bar greater than the opening force. At The transport pressure is reduced by <1.4 bar Impact cylinder with the dominant opening force indented. The quantity of material to be conveyed increases accordingly According to the wider open regulator, the transport pressure rises again.

Rough calculation example:

counter: control piston diameter d = 100 mm
Control piston diameter D = 400 mm
Piston rod diameter negligibly small
maximum resistance due to friction of the regulating and control piston z. B. F _w = 1000 N
Pressure regulator setting for "on" :. p₁ = 1.7 bar
Min. Transport: p₃ = 1.4 bar
Control pressure from the stop cylinder: p₄ = 6.0 bar
total: stop cylinder force: F _A = x
Piston diameter from the stop cylinder: d1 = x
Opening force = d² × 0.785 × p₃ + D² × 0.785 × p₁ + F _w
= 10² × 0.785 × 14 + 40 × 0.785 × 17
+ 1000 N
= 1099 + 21 352 + 1000
= 23 451 N
Closing force of the control cylinder
= D² × 0.785 × p₃
= 40² x 0.785 x 1.4
= 17,584 N

Around the stop cylinder from a transport pressure of 1.4 bar to be flexible, a piston diameter of 112 mm can be selected.

The advantages of the volume flow controller are that self-sufficient controllers like a valve regardless of additional external energies can be installed in delivery lines can. The overall efficiency of solid materials handling systems is cheaper because the funding time is kept optimally short, Blockages and thus malfunctions can be avoided and the Wear in the delivery lines is kept to a minimum. The solution according to the invention can be used anywhere where dusts and granular bulk goods pneumatically through Rohrlei be transported. Without major modifications, the Subsequently insert the controller into the existing solids conveyor system be built.  

A possible embodiment of the invention is in the Drawing shown and will be described in more detail below ben.

It shows

Fig. 1 is a sectional view of the regulator,

Fig. 2 control gap plan view of Fig. 1 at 50% stroke,

Fig. 3 control gap plan view of Fig. 1 at approximately 90% stroke,

Fig. 4 installation of the regulator behind a bottom, to be emptied pressure feed vessel with additional pneumatic control as "on-off" -Organ

Fig. 5 Installation of the controller behind a pressure vessel to be emptied at the top without additional pneumatic control as an "open-close" organ.
Position description Fig. 1:

The controller housing 1 with a tapered inner bore to the radial seal package 3 leads to the beveled control piston 2 and is traversed vertically from above to below by solid amounts. The lantern 4 , which has a longitudinal slot for the anti-rotation cam 20 , which is connected to the control piston 2 , is screwed onto the housing 1 . The cylinder 5 is screwed onto the lantern 4 . The piston rod 7 with the control piston 6 is screwed onto the control piston 2 . At the free end of the cylinder 5 , a sleeve 8 is fastened with an internal thread, which can accommodate the sleeve 9 with an external thread and thus the cylinder 24 with a piston rod 25 . The free ends of the piston rod 7 and 25 are crowned. The pneumatic pressure control valve 10 with overpressure relief regulates a high primary pressure down to a lower secondary pressure and immediately builds up a secondary pressure that builds up from the outside to the secondary pressure set via the muffler 11 . The throttle check valve 16 allows compressed air to flow unthrottled through the check valve into the cylinder 5 , outflowing air from the cylinder 5 can be throttled so that the opening speed is adjustable. The solenoid valve 19 is open when de-energized, so that the pneumatically controlled valves 12 + 14 are also open when de-energized. The Druckregelven valve 17 regulates, just to save compressed air, a high primary pressure to a low secondary pressure. Filters 18 and 28 are installed to protect the pneumatic components. The runner 22 is supported when the closure function of the volume flow controller is activated, just before the control piston 2 is too large, on the support roller 21 so that the inclined surface of the control piston 2 is pressed firmly against the incline of the wear insert 23 , that the controller can be described as bulk-tight.
Position description Fig. 4:

The positions. 1 - 25 and 28 are equal to the positions in Figure 1. The pressure vessel conveyor 35 is a vessel which can be filled through the opened closing member 26 with bulk goods. When the valve 26 is closed, opening the solenoid valve 33 via a pressure regulating valve 32 partially introduces compressed air as a loosening gas into the vessel 35 , so that pressure builds up in the vessel 35 . Line 27 is the beginning of a conveyor line. Through the propellant nozzle 31 flows, with the solenoid valve 30 switched by the air quantity control valve 29, a fixed amount of conveying air which is independent of the inlet pressure (for example 6 bar). The pressure switch 34 initiates the promotion when the vessel pressure is reached.
Position description Fig. 5:

The position 1 - 11, 13, 14, 16, 24 - 36 are identical to the positions of Figures 1 and 4...
In Fig. 5 the volume flow controller Fig. 1 is shown without the closure function. Items 12 , 15 , 17 - 19 , 21 - 23 are not installed here. As a replacement for the shutter function, a commercially available shutter valve 36 is built. All other positions have already been described.
Functional description ( Fig. 1-4):
Basic position before funding process:

Silo 35 is empty and depressurized. Solenoid valve 19 , it is excited and thus switched. As a result, the valves 12 + 15 also switched. Through the bore 14 to the Kol ben 6 pressure is switched on, the bore 13 is connected via valve 12 and silencer 11 to the atmosphere. The control piston 2 stands with its runner 22 on the support roller 21 and presses its inclined surface in the outer region tightly against the closing insert 23 . Valves 30 and 33 are de-energized and therefore blocked.
Filling the silo:

Valve 26 opens and bulk material is passed into the vessel 35 . After reaching a certain filling mark, valve 26 closes, valve 33 opens and an excess pressure builds up, regulated by valve 32 of e.g. B. 1.5 bar.
Start of the funding process:

Pressure switch 34 reports vessel pressure is present. Valve 30 is switched and thus flow z. B. constant 1000 Nm³ / h compressed air through the control valve 29 in the driving nozzle 31 and thus in the delivery line 27th Without conveyed goods, a low transport pressure of z. B. 0.5 bar. Valve 19 is de-energized, the valves 12 and 15 turn in the basic position (passage - as drawn), through bore 13 builds z. B. 1.8 bar of compressed air from valve 10 regulated in front of the piston 6 and the piston 6 and thus the control piston 2 move up and the bulk material can flow freely into the delivery line. During the opening travel, compressed air flows through bore 14, possibly throttled, by valve 16 through filter 28 combined with the constant 1000 Nm 3 / h compressed air through additional nozzle 31 into delivery line 27 . Due to the beginning of the flow of material to be conveyed, the transport pressure increases by 0.5 bar. In accordance with the pressure increase, the flow velocity in the conveying line 27 decreases. If the adjustable cylinder 24 is set so that the open position is limited, the free end of the piston rod 7 abuts against the free end of the piston rod 25 . The resistance of the piston of Zy cylinder 24 initially limits the further ascent. If the transport pressure drops, for whatever reason, extremely, the differential force, due to the decreasing closing force, is greater and pushes the piston 6 further and thus the piston rod 25 into the cylinder 24 . The volume flow controller can thus open up to the maximum.

If the delivery pressure rises to <2 bar, there is a risk of blockages. In this case, press the <2 bar through the bore 14 on the control piston 6 , the pressure regulator 10 blows via its secondary control, the increasing pressure which acts on it through the bore 13 , due to the piston surfaces being equal, into the atmosphere. The control piston 6 pushes with its piston rod 7 the control piston with its inclined surface so long in the För derstrom and thus reduces the discharge amount until the transport pressure decreases to about 1.7 bar. If the transport pressure drops further, the positive differential force decreases compared to the constantly acting opening force down to the negative differential force, the control piston pulls the control piston back out of the flow and thus the discharge quantity and the discharge pressure increase again.
End of the funding process:

Pressure switch 34 switches at z. B. <0.5 bar. This means that the upper pressure of 1.5 bar, which was kept steady by the valve 33 during the promotion, has relaxed in the feed line 27 . This in turn means that there is no longer any material to be conveyed in the vessel 25 . After a short blow-off time, valves 30 and 33 are de-energized and valve 19 is energized. The valves 30 and 33 close, the valves 12 and 15 switch and thus the control piston 6 presses the control piston 2 with its skid 22 against the support roller 21 and thus into its sealing seat via its pressure coming through the bore 14 .
Functional description Fig. 5:

The control function is the same as in the functional description Fig. 1-4. Only a volume flow controller without a locking function is shown here. The "open-close" function is performed by valve 36 .
The two vehicle modes (regulate with "open-close" function and only control function) can be used independently of any pressure vessel. The pressure vessels in FIGS. 4 and 5 are only examples.

Claims (7)

1. Volume flow controller for pneumatic solid matter, characterized in that the controller housing ( 1 ) for installation in pipelines has a side at an acute angle, tapered inside the passage, which has a cylinder at the free end with the lantern ( 4 ) ( 5 ) with oversized piston ( 6 ) takes on, which in turn is acted upon by a constant force for direction "on" with a constant pneumatic pressure and for direction "to" a differential force developed according to the two pressures, which then on the piston rod ( 7 ) the twist-proof and radially sealed control piston ( 2 ), with the same outside diameter as the outside diameter of the wear insert ( 23 ) of the controller and at the free end with half the housing angle = β), the beveled tip extends or into the solids flow that the discharge quantity always optimally corresponds to the most favorable flow properties. 2. Flow controller according to claim 1, characterized in that the pneumatic control through valve (12, 15) and (19) and the fittings (part 21-23) which can be Volumenstromregelven til also used as a shutter valve. 3. Volume flow controller according to claim 1 and 2, characterized in that the slope of the control piston ( 2 ) and the Ver wear insert ( 23 ) can be made of hard metal or ceramic. 4. Volume flow controller according to claim 1, characterized in that the stop cylinder ( 25 ) adjustable in position, the piston rod ( 7 ) with the control piston ( 6 ) in the upward travel until the differential force of the control cylinder is so great due to the decreasing transport pressure is that the piston of cylinder ( 24 ) pushes the compressed air back into the network and thus clears the way for the maximum opening of the volume flow controller. 5. Volume flow controller according to claims 1-4, characterized, that the control cylinder with its pneumatic control also every commercially available type of shut-off and control valve can drive. 6. Volume flow controller according to claims 1-4, characterized in that the oblique control piston ( 2 ) with its housing ( 1 ) and parts ( 20 - 23 ) can be driven by any other actuator. 7. Volume flow controller according to claims 1-6, characterized, that the controller even when pumping mushy liquid Gü tern can be used.