CH640333A5 - Mechanical/hydraulic metering apparatus - Google Patents

Description

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PATENT CLAIMS 11. Dosing device according to claim 10, thereby

1. Mechanical-hydraulic metering device with one indicates that the metering pump input via two metering pumps for metering chemicals into a flow-stroke ends of the metering piston (23) has associated suction valves, in particular in a water pipe, thereby (27) with a suction pipe (26 ) for sucking in the metering valve, that one is connected to the flow rate in the micros (25) and that the metering pump from the liquid line (3) and the metering counterpressure proportional to both stroke ends of the metering piston (23) Differential pressure between two points (11, 12) of the arranged pressure valves (30) and a metering line (31) with the differential line (3) adjusting the differential pressure transmitter (10) metering point (32) of the liquid line (3) is provided in connection and that the high pressure and low pressure side (11, stands.

12) of the differential pressure transmitter (10) to a servo control io 12. Method for operating the metering device according to a

(20) for actuating the metering pump (22, 23) are switched. nem of claims 1 to 11, characterized in that

2. Dosing device according to claim 1, characterized for the movement of the dosing pump (22, 23) in each case only that the differential pressure transmitter (10) changes the Po differential pressure proportional to the dosing back pressure from an energy required for the full dosing stroke. tential of the differential pressure is taken.

derenden, in the liquid line (3) and 13. Process according to claim 12, characterized in

the flow cross-section (40, 61) of the same narrowing net that the differential pressure depending on the metering

Throttle body (41, 60) and a pressure proportional to the differential pressure and through which the liquid line (3) flows

tional to the flow rate changing nozzle (48.62) is set in the flow rate,

the liquid line (3). 14. The method according to claim 13, characterized in

3. Dosing device according to claim 2, characterized in that the differential pressure shows both with increasing dosing, that the throttle body (41, 60) with respect to a counterpressure and with increasing flow rate proportions narrowing of the flow cross-section (40, 61) Liquidation is enlarged.

cable (3) is spring-loaded (46,66).

4. Dosing device according to claim 3, characterized

records that the throttle body (41.60) via a piston 25

Rod (42,63) and a control piston (44,65) in a Zy- The invention relates to a mechanical-hydraulic Do-

Linder (43, 64) is such that the metering back pressure acts via a metering device with a metering pump for metering in a metering back pressure line (47, 67) on the throttle chemicals in a liquid line, in particular in a rear side of the control piston facing away from the body, and water line. Furthermore, the invention relates to a

that this rear of the control piston is also spring-loaded to operate the metering device.

is encumbered (46.66). A dosing device is already known from AT patent 27 99 17.

5. Dosing device according to claim 4, characterized in known direction for chemicals. One uses a drawing that the cylinder guiding the throttle body (41) into the reservoir, (43) and the drive connected to the back of the cylinder (43), for example by means of an electrical circuit, metering counter pressure line (47) entirely within the liquid circuit. 35 depending on the amount of the flowing medium (3) and that, in which the throttle body (41) is controlled. The circuits developed for this are necessary on the liquid line (3) downstream of the nozzle (48) and often unsatisfactory for the operational practice - counterpressure line (47) up to a reliable in the flow direction (2). For this purpose, contacts to be adjusted to the area of the liquid line lying behind the nozzle (48) have been developed, which are guided in the delivery (3) (FIG. 2). 40 medium lack trigger an electrical impulse, which

6. Dosing device according to claim 2, characterized in turn then stops the pump drive. It must therefore be noted that the nozzle (62) is an adjustable perforated nozzle and that external energy is used here, a fact that the throttle cross-section of the nozzle is coordinated in such a way that the dosing pump (22, 23) resulting from additional operational problems regardless of their stroke direction.

speed always performs a full stroke (Figure 3). 45 In contrast, the new facility is to be built

7. Dosing device according to claim 2, characterized in working energy and large dosing quantities against pressure, which means that the nozzle (48) is composed of an injector nozzle part against the system pressure or internal pressure (49) and a diffuser (50), the Injector and the nozzle part (49) to be supplied with the dosing agent can dose the low pressure side (12) of the differential liquid. The pressure against which the pressure transmitter (10) forms and which is to be dosed with the servo control (19, 20) 50 is also coupled below as a dosing back pressure (FIG. 2). designated. The invention also has the object

8. Dosing device according to claim 1, characterized in that the entire flow through the liquid line shows that as servo control a working piston (20) is seen before the amount of liquid or water, ie also the one whose two end faces are via reversed amount of lei , which is required to drive the metering pump lines (15, 17) alternately with the high and the 55, - to be recorded proportionally and accordingly to set the low pressure side (11, 12) of the differential pressure sensor (10) in the amount of the metering chemical.

There is an operative connection, and that the working piston (20) is coupled to the metering device according to the invention by a metering piston (23) of the metering pump (fi solution in that one is used to flow through the gur 1). Liquid line and proportional to the dosing back pressure

9. Dosing device according to claim 8, characterized in that the differential pressure between two points of the liquid line is provided for the reversing of the high and low pressure adjusting differential pressure transducers and pressure side (11, 12) of the differential pressure transducer (10) The high and low pressure side of the differential pressure gene in the liquid line (3), the water motor (4) is also provided on a servo control for actuating the metered four / two-way spool (7). 65 pumps are switched.

10. Dosing device according to claim 9, characterized. It is advantageous that the differential pressure sensor is characterized by one that, in order to drive the slide (7), an eccentric set to an output shaft (5) of the water motor (4) which is proportional to the differential pressure changing, switched into the liquid line and (6) is provided. Flow cross section of the same restricting throttle body

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and there is a nozzle in the liquid line which changes the differential pressure in proportion to the flow of the working piston with a metering piston of the metering pump. coupled, in particular is firmly connected. Working piston

According to the method according to the invention, for the loading and dosing pistons, a movement of the dosing pump via the piston rod can in each case only form the component that is currently connected to the vol.

The energy required for the metering stroke is taken from the potential of the diff. An advantageous means for reversing the supply lines of the reference pressure. Accordingly, the differential pressure of the cylinder of the working piston to the high and low as a function of the metering back pressure and of the rig pressure side of the differential pressure transducer consists in that the flow rate flowing through the liquid line is set to drive the slide valve on an output shaft of the. According to the invention, it is therefore favorable if the eccentric is set for the water motor. A four / two-way slide can be considered as the slide of the differential pressure with increasing metering back pressure 10.

as well as proportionally increasing with the flow rate. Furthermore, a metering pump can be used which is increased. the dosing chemical sucks in via a suction line and the method according to the invention is characterized in each case by the following stroke into the dosing line via a dosing line that for the movement of the dosing pump only releases the liquid line. The metering pump, the energy 15 just required for the full metering stroke, can both suck in on each stroke and be taken from the metering potential of the differential pressure. Chemical discharge when the suction line and the out-through is achieved so that for the pump movement there is no constant differential pressure in front of or behind the confluence, but only such a proportion that the pressure in the metering piston leading to the metering piston is branched off sufficient to move the metering and, if in the suction line and the discharge line, ven pump by a full stroke. As a result, the 20 tiles are used that only let the dosing chemical flow in the direction of the desired proportionality between the total flow to the dosing point.

flow rate and the following are referenced with reference to the enclosed

Guaranteed quantity of the metered chemical. Since the dif- ferent schematic drawing shows exemplary embodiments of the

reference pressure as a function of the metering pressure and in the metering device according to the exhaust pressure described. Show it:

dependency on the flow rate proportional 25 Fig. 1 shows a functional diagram of the dosing device,

the device according to the invention has a differential pressure transmitter for controlling the differential

known devices have the advantage that the total pressure depends on the flow rate and system.

liquid or stem pressure or metering back pressure flowing through the liquid line and

Amount of water, that is also that which is necessary to the Fig. 3 a modified compared to Fig. 2 construction

To drive the metering pump is recorded proportionally. 30 of the differential pressure sensor.

The differential pressure sensor therefore consists of a throttle valve.

body and a nozzle, both of which went into the liquid line, that it was a metering device for metering

are switched on. To make the chemical of the invention act in water. Basically, according to the metering device, even at the smallest differential pressures, the invention responds to metering into any one. According to the invention, the throttle is liquid.

1 in the functional diagram according to FIG. 1, it is assumed that a cylinder is guided that the metering back pressure via a water 1 in the direction of the arrow 2 from the water line 3 in the metering back pressure line to the water motor remote from the throttle body 4 flows, whereby the output shaft 5 of the opposite rear side of the control piston acts and that this water motor 4 is driven and is also spring-loaded on it on the rear side of the control piston. It 40 eccentric 6 a four / two-way slide 7 is so that the throttle body drives the actuating rod 8 in the direction of arrow 9 except through the dosing, counter pressure with a view to narrowing the flow-In the water line 3 is also a generally 10 cross-section is also acted upon by a spring force. A drawn differential pressure transmitter switched on. Due to this favorable mechanical design, it is when it is caused that there is a higher throttle body at point 11 of the water line 3 via a piston rod and a control pressure than at point 12. The point 11 of the piston is guided into a cylinder, the metering counter pressure water line 3 with higher pressure is connected via a line 13 via a metering counter pressure line to the throttle body with an input of the slide 7, while the point 12 connected via the opposite rear of the piston is connected with low pressure of the water line 3 via one and the rear of the piston spring-loaded line 14 is coupled with another input of the slide 7. Is 50 pelt.

In a simple embodiment, the one for changing the slide 7 has two outputs, namely a line of the differential pressure proportional to the flow rate, which leads to the one cylinder space 16, and a line 17,

seen nozzle designed as an adjustable perforated nozzle. The to the other cylinder chamber 18 of the working cylinder 19th

Throttle cross section of this nozzle should be coordinated, leads. Between the two cylinder spaces or cylinder parts

that the metering pump is independent of its stroke speeds 16 and 18, the working piston 20. This is always a full stroke. It is even more favorable via a piston rod 21 with the

it when the nozzle is firmly coupled as a combination of an injector nozzle and introduced metering piston 23.

Nes diffuser is formed because then by the effect of the diffuser generated by the differential pressure sensor 10, part of the differential pressure drop between the high pressure point 11 and the pressure falling at the nozzle can be recovered. With this connection 60 low pressure point 12 of the water line 3 it is caused that

Order, the injector nozzle forms the low-pressure side of the working piston 20 via the four / two-way slide 7

Differential pressure sensor. The injection nozzle is accordingly expediently coupled directly to the servo control via the line 15 and the cylinder space 16. and in the direction of arrow 24 to the right or when switching the

As a servo control, a working piston can be provided in the slide 7 via the line 17 and the cylinder chamber 18, the two end faces of which are moved to the left via reversed lines 65 arrow direction 24. In the

alternately with the position drawn high and low pressure, the working piston 20 of the differential pressure transducer is in operative connection, being to the right, since the higher pressure in the piston chamber 16

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Position 11 of the water line 3 is present and the lower pressure of the point 12 of the water line 3 connected to the slide 7 via the line 14 is present in the cylinder chamber 18.

At the same time as the working piston 20, the metering piston 23 is moved back and forth because of the fixed coupling via the piston rod 21. If the movement takes place to the right in the direction of arrow 24 according to FIG. 1, the dosing chemical 25 is sucked into the dosing cylinder space 28 (to the left of the dosing piston 23) via the suction line 26 and suction valves 27. At the same time, the metering chemical in the right metering cylinder chamber 29 is expelled or displaced by the metering piston 23 and metered into the water 1 guided in the water line 3 via a pressure valve 30 and a metering line 31 at the metering point 32.

An embodiment of the differential pressure sensor 10, which is only symbolically shown in FIG. 1, is shown schematically in FIG. 2. The differential pressure transmitter 10, which generates the required differential pressure as a function of the system pressure or metering counterpressure and the flow rate, is switched on in the water stream 1 flowing through the water line 3 in the direction of the arrow 2. In the flow direction of the water 1 upstream of the differential pressure transmitter 10, the line 13 is enclosed at the point 11 of the higher pressure. In contrast, the line 14 is located at the point 12 of the low pressure - viewed in the direction of flow of the water 1 - at the outlet of the differential pressure sensor 10.

The differential pressure transmitter essentially consists of a throttle body 41 which more or less closes the flow cross-section 40 of the water line 3 and which is firmly connected via a piston rod 42 to a control piston 44 guided in a cylinder 43 and is movable in the direction of arrow 45. A spring 46 is also provided in the cylinder 43, which presses the piston 44 against the flow direction 2 of the water 1 with a view to narrowing the flow cross-section 40. The rear side of the cylinder 43 opposite the piston rod 42 is connected via a pipe 47 - viewed in the direction of the arrow 2 - to an area 51 inside the water line 3 behind the differential pressure transmitter 10. The side of the cylinder 43 opposite the tube 47 is opened to the outside via a vent line 52.

The differential pressure transmitter also has a nozzle, generally designated 48, which consists of the combination of an injector nozzle 49 and a diffuser 50. The injector nozzle 49 simultaneously represents the low pressure side 12 of the differential pressure sensor 10 and is directly connected to the low pressure line 14.

2, the differential pressure can be controlled both as a function of the metering back pressure or system pressure and as a function of the flow rate. The metering back pressure, which is present at point 51 - seen in the direction of arrow 2 - behind the differential pressure transmitter 10, is removed from the system via the pipe 47 and acts on the control piston 44 guided in the cylinder 43. The cross section of the latter and that of the throttle body 41 should be be adjusted so that the differential pressure also increases with increasing pressure in the system. The control of the differential pressure depending on the flow is achieved by the combination of the injector nozzle 49 and the diffuser 50. As the flow rate increases, the pressure at point 12 behind injector nozzle 49 is reduced and the differential pressure between points 11 and 12 of water pipe 3 is increased.

A particular advantage of the differential pressure transmitter 10 according to FIG. 2 is that part of the differential pressure is recovered by the action of the diffuser 50. The metering device according to the invention then represents only a slight resistance in the water line 3.

Also in the differential pressure transmitter 10 according to FIG. 3, in the water line 3 of the water 1 flowing in the direction of the arrow 2 between the point 11 higher pressure and the point io 12 lower pressure, a throttle body 60 for opening the flow cross-section 61 to a greater or lesser extent and a nozzle 62 switched on. The throttle body 60 is connected via a piston rod 63 to a control piston 65 guided in a cylinder 64. In this case too, a spring 66 is provided inside the cylinder 64, the spring force of which acts in such a way that the control piston 65 is pressed in the direction of the throttle body 60 in order to narrow the flow cross section 61. The rear side of the cylinder 64 opposite the throttle body 60 is connected via a line 67 to a region of lower pressure in connection with the differential pressure transmitter 10. The end of the latter opposite the connection of the line 67 to the cylinder 64 has a vent 68. As in the device according to FIG. 2, therefore, no force acting against the force of the spring 66 is exerted on the control piston 65 from inside the cylinder 25.

The nozzle 62, which is designed as an adjustable perforated nozzle, is located in the flow direction 2 of the water upstream of the connection point of the line 67.

The differential pressure transmitter 10 according to FIG. 3 also controls the differential pressure as a function of the flow rate and system pressure or metering back pressure. J5 This happens as follows: The water 1, which flows in the direction of the arrow 2, lifts the throttle body coupled to the control piston 65 via the piston rod 63 against the force of the spring 66 and flows through the flow cross section 61 through the nozzle 62 designed as a throttle 40 Position 11 thus creates a differential pressure compared to point 12. The spring 66 - like the spring 46 according to FIG. 2 - causes an initial differential pressure to exist even with the smallest flow rates.

The control of the differential pressure as a function of the metering counterpressure is brought about by the fact that water flows from line 3 via line 67 into cylinder 64 and acts on control piston 65 from the rear side thereof, which is opposite throttle body 60. The cross section of the control piston 65 and the throttle body 60 should be matched so that the differential pressure also increases with increasing pressure in the system or in the water line 3. The control of the differential pressure as a function of the flow rate takes place in the device according to FIG. 3 with the aid of the perforated nozzle 62, in which the differential pressure increases quadratically with increasing flow rate. The throttle cross section of the adjustable nozzle 62 designed as a perforated nozzle should be adjusted so that the metering pump according to FIG. 1 always executes a full stroke regardless of the stroke speed. 60 Although the differential pressure transmitter 10 according to FIG. 3 requires a greater energy absorption from the flowing water 1 than that according to FIG. 2, it is associated with less effort because of its simple construction.

C.

3 sheets of drawings