DE1703545A1 - Valve controlled differential pump - Google Patents

Description

• Valve controlled differential pump

The subject of the present invention is one with gas or steam operated differential pump for conveying and metering liquids. .- ■■ '. *

Flywheelless, steam powered reciprocating pumps, for example Simplex and duplex pumps have long been known and are used today often used as boiler feed pumps * Through direct coupling of steam and pump cylinders is a simplification here of the 'pump set, but is due to the indirect Control of steam consumption, very high per working stroke. A seal

SAD OWQiNAt

109883/0310

By / 0r

PLA 68/1220

The front space to the drive space can also only be done by means of stuffing box screw connections can be achieved, which leads to a considerable increase in friction losses.

The object of the present invention was now to provide a controller for a gas or steam powered pump, especially for smaller ones Demanding performance to find that avoids the disadvantages mentioned and the pistons of the pump are wholly or partially replaced by membranes.

The solution to the problem is that the control organs the pump consist of mechanically and pneumatically or mechanically operated three-way valves.

One of the advantages of the new valve-controlled pump is mainly in it seen that it is continuously variable from ^ O _! __ maximum. So can the amount control according to one embodiment of the invention done in such a way that one of the temperature or the pressure dependent needle valve in the gas or steam supply line to the control valves is installed. Of course, other controlled variables can also be used instead of the temperature or the pressure. When dosing the liquid fuel in a fuel element, in particular to a reformer connected upstream of the fuel element and used to generate hydrogen, For example, the consumer current of the load connected to the fuel element can also be used for quantity control, see above that with increasing load also the amount of liquid conveyed into the reformer increases.

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PLA 68/1220

Another essential advantage is seen in the fact that the working and The delivery piston of the pump can be wholly or partially replaced by diaphragms or bellows. This can even increase the efficiency the pump can be increased, on the other hand, the pump can also easily are used for toxic and / or chemically aggressive gases, vapors and liquids. Pump, controller and control switch work completely explosion-proof, and are therefore used as a dosing unit for a hydrogen generator, e.g. a reformer, especially suitable. ■

The subject of the invention will now be based on the following figures explained in more detail.

In Fig. 1, 1 represents a simplex pump with the membranes 2 and 3. The liquid to be conveyed is sucked in via the pipe socket 4 · and a check valve and a check valve and the pipe socket 5 pushed out of the pump. With 6 and 7 are mechanical controlled three-way valves, with 8 and 9 pneumatically controlled three-way valves and with 10 an on and 11 an off button denotes »Jj

The working gas is first passed through the line 12, the pressure-controlled needle valve 13 and the pipe 14 to the pneumatically controlled circuit breaker 8, which is "hereinafter referred to as LS, and via the pressure reducer ^ 15 (eg control pressure 1.4 atü), through the line 16, the blanking button 11 and the line Γ · ^{7 are} fed to the on-button 10. If the button of the on-button 10 is pressed, the on-button switches over and the control air flows through the line.

BAO OWGiNAL 10 9883/0310

- 5 - ■ By / Or

| - PLA'68 / 1220

lines 18 and 19 in the right chamber of the push button, where. switch to the button position you pressed initially by pressing the membrane holds on. At the same time the lines 20, 21 and 22 filled with gas. Because the pump is at rest thanks to its spring is pushed into the lower position, the three-way valve is located 6, hereinafter referred to as microswitch MS, through the right switching rod of the pump in the reverse switching position as drawn, so that from line 22 control air in the MS 6, the Line 23 and the MS 9 can flow in. Arrived via line 24 the control fragrance to the membrane of the MS 9 and causes the switch there of the MS. This switch position is retained even if the MS 6 later switches over and the control air supply is via the Line 23 is interrupted because the switched switch position of MS 9 is maintained via line 20, MS 9 and line 24 remain. The membrane of the LS 8 is via the line 20, MS 9 and

line 25 is loaded with the control pressure, LS 8 also switches over as a result and releases the path for the working gas in line 14 to the membrane chamber of the pump via line 26 - *. The pressure of the working gas now moves the membrane 3 upwards, so that MS 6 is first lifted off the switch rod and jumps back into the position shown. The line 23 is vented via the opening 27 of the MS 6. When the pump membrane reaches its upper end position, the left switching rod actuates the MS 7 and switches it over. The control air in line 21 now flows through MS 7 and line 28 in MS 9, which switches this switch to the position shown

4 - By / Qr

109883/0310

ORIGINAL INSPECTED

PM 68/1220

'leads. Thereby «earth via opening 27, MS 6, line 23, 24, MS 9 and the line 25 as well as the associated membrane spaces are vented »LS 8 goes into the switch position shown here ' back and vents the membrane space of the pump via line 26, so that the diaphragms 2 and 3 and switch rods are pressed down by the spring.

With the downward movement of the membranes and switch bars first the spring force through the left switching rod of the pump from MS 7 free and the switch jumps to the position shown return. The line 28 is vented via opening 27a. MS 9 is held in the position shown by the spring force. When the lower membrane layer is reached, the right handrail kicks in the pump is in function and initiates the second working stroke.

ν ■ ■ - ·

If the pump is to be switched off, the button of the blanking button 11 is pressed so that the switching function is activated. turns. Through this the control air supply from line 16 to line 17 is blocked. At the same time the lines 17, 18, 19, 22, 20 and 21 are vented, the spring force of the push button becomes effective and the push button 10 jumps back into the position shown. * is the Off button is no longer actuated, it goes into the position shown back and allows the control air to flow in line 17. By pressing of the push button 10, the pump can be put into operation again.

In the simplex pump described in FIG. 1, the pneumatic ones work Three-way valves with one in process engineering

109883/0310

INSPECTED - 5 - By / Or

usual control pressure of about 1.4 atü and control the for one higher »working pressure adapted to the simplex pump, for example 10 atü designed circuit breaker. Should the pump, but only are operated with a working pressure of up to 1.5 atü, pressure reducers and circuit breakers are not required. The microswitch 9 can then can be connected directly to the simplex pump.

According to a further embodiment of the invention, a ™ duplex pump can also be operated mechanically and pneumatically or mechanically Three-way valves are controlled. Such an embodiment is shown in FIG.

The supply of the working gas a takes place here through the line 31, once via the pressure-controlled needle valve 32 and lines 33 and 34 to LS -35 and via line 36 to LS 37, on the other hand via the pressure reducer 38, the line 39, the scanner 40 and the lines 41 and 42a to the push button 43. From the ~ Line 41 leads the line 42b to the MS 44, the line 45 to the MS 46 and the lines 45 and 47 to the MS 48. The pump 49 is in the pig. drawn in rest position. When the push-button 43 is actuated, the switching lever jumps over and that in the line 42a located gas atrömt through switch 43 and lines 50 and 52 into the lower membrane space of the LS 35. As a result, LS 35 is switched over and the working gas in line 34 flows Via LS 35 and the line 53 in the right diaphragm chamber of the pump 49, which causes a movement of the diaphragms and the shift linkage

10988 ^ / © 3 10 _{Ώ / Λ}

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BAD OWGINAL

PLA 68/1220

to the left. At the same time, control gas flows from line 50 via line 54 into the lower membrane chamber of the MS 55 and also switches it over. The control gas from line 56 can now flow through MS 55 and lines 57 and 54 into the lower membrane space of MS 55. In this way, the control pressure pulse given by the push-button is retained, even if the push-button is no longer actuated and has jumped back into the initial position shown. Control gas continues to flow from line 57 via line 58 into the upper diaphragm space of MS 44, where it increases the spring pressure. This state is maintained until the diaphragms of the pump 49 have been pushed to the left so far that the upper right switch rod of the pump compresses the spring in MS 46 and switches the valve. As a result, the control gas flows from line 45 via MS 46, line 59 »MS 44 and lines 60 and 61 into the lower diaphragm space of MS 44. However, MS 44 does not yet switch over, since spring pressure and control pressure from line 58 counteract this. The control gas also reaches the upper membrane space of the MS 55 * via the line 62 so that the MS 55 switches back to the position shown. Lines 58, 57, 54, 52, 51 and 50 are vented via line 63 and MS. By venting the line 58, the MS 44 now also switches over and the control gas from line 42b holds the MS 44 in the switched position via the lines 60 and 61. Control gas is now introduced into LS 37 via line 64, causing it to switch over, so that working gas from line 36 via LS 37 and line 65 into the left diaphragm space of the pump _; got.

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17035Λ5

The working diaphragm, conveyor diaphragm and switching rods move afterwards

to the right.

By venting the line 52 above, LS switches to the position shown, so that the right diaphragm chamber of the Pump 49 is vented via line 53 and LS 35. As a result of Movement of the pump diaphragm to the right releases the spring force of the MS 46 and a switchover to the position shown takes place. the Line 59 is thereby vented via MS 46. The right movement of the pump diaphragms continues until the left selector rods MS 48 switches over and the control gas in line 47 through MS 48, line 63, MS 55 and lines 57, 58, 54, 52, 51 and 50 flows and the switching operations are repeated.

The pu, mpe is shut down by pressing the blanking button 40. As a result, the supply of the control gas from line 39 to line 41 is interrupted. At the same time, the Control gas lines 41, 42a, 56, 42b, 45 and 47. Circuit breaker » and microswitches receive no control gas and switch back to the positions shown by the spring forces acting alone. Even the pump that is no longer pressurized by working gas remains' are in the center position shown. The system can be restarted by pressing the push button.

Of course, the pumps shown in FIGS. 1 and 2 can also be operated without an on / off button. The in-

- ⁸ - 1 α 9.8,8 3, / * 0 3 1 0 ^B y / ' ^Or

The pump is then started up and shut down solely via the needle valves 13 and 32.

In the arrangement shown in FIG. 2, the liquid is sucked in via the pipe 66 and conveyed further via the pipes 67, 'whereby check valves are required for suction and pressure pipes are.

As mentioned earlier, the valve operated differential is £ pump infinitely variable from 0 to maximum, a needle valve being used to control the amount in a manner known per se can. ·

According to another embodiment of the invention, however, can the pump can also be continuously regulated from 0 to maximum in such a way that it is placed with the control elements in a gas-tight vessel, the pressure of which depends on the connected Consumers are continuously changing. The effective approach _ Drive and delivery surfaces are dimensioned so that the pump comes to a standstill at the set maximum pressure and at reaches its maximum delivery rate at the required minimum pressure.

Such a quantity control is particularly suitable for those cases in which the pump is a liquid fuel, for example CH ^ OiJ, in a pressure vessel (reformer), in which the liquid Substance is subjected to catalytic cleavage and from which

BATH ORIGINAL

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PLA 68/1220

formed gas, e.g. hydrogen and COp, the hydrogen in one Fuel element is converted into electrical energy. The hydrogen formed and optionally purified is here first used as control and working gas of the pump and then consumed in the connected fuel cell battery. Depending on the hydrogen requirement of the fuel element the gas pressure in the above-mentioned vessel changes and thus the amount of liquid conveyed. Accordingly, with increasing hydrogen consumption the pressure in the vessel is reduced and the output of the pump is increased. If the hydrogen consumption decreases, the reverse is true the pressure increases and the pump output is reduced. This quantity control will be explained in greater detail later with reference to FIGS. 5 and 6.

For pumps with particularly low power, it is advisable according to a further invention to replace the microswitches 6, 7, 46 and 48 shown in FIGS. Such a switch is shown schematically in Fig. 3.

In Fig. 3, 71 represents the pressure pin moved by the sucker rod represents, who via the leaf spring 72a and U-spring 72b the switching lever 73 only after reaching a certain distance covered the U-spring 72b and lever 73 makes the spring jump. Likewise, when the pressure pin is relieved and moved back, a rapid one takes place Jumping of the lever, so that a pneumatic control also with

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BATH

PLA 68/1220

very low piston speed, i.e. with minimum power the pump, is possible. With 74, 75 and 76 are those for pump control required valve tubes. The inlet of the control gas takes place through the pipe 74- and the transmission into the Membrane space of the pump via tube 76; Purely the necessary ventilation the pipe 75 is provided.

Two levers 73 for simultaneous switching can also be attached to the U-spring 72b be hinged by two three-way valves. Are 2 monostable three-way valves according to Fig. 3 by a common U-spring 72b and the necessary switching path of the spring mechanism is selected to be the same as the piston path of the pump or by a simple one Leverage adapted to each other, this combination can be a Replace bistable double switch with pressure-relieved valves. The pressure relief on the common U-spring 72b, 'leaf spring 72a and plunger 71, takes place here in that the forces act on the two Valve plates are the same size but open in the opposite direction the two interconnected levers 73 act as both valves can be operated with the same control pressure and the diameter of the valve openings can be selected to be the same size. From the differential pump only one switching rod is then to be led out, which is on the common plunger 71 is effective.

According to a further embodiment of the invention, however, instead of the monostable jump mechanism according to FIG. 3, a bistable can also be used Jump mechanism can be used, which is equipped with two to four pneumatic

- 11 - By / Or

1088S3 / 0310

PLA $ 8/1220

table porridge-way valves can be combined. Such a bistable multiple switch is as. Double switch especially for * Suitable for controlling duplex pumps. This means that the Pig. 2 three-way valves 44 and 55 used as holding relays are superfluous. In addition, as with the monostable jump mechanism according to Fig. Switching speed and switching force are independent of the release speed and release force, i.e. operational reliability is ensured even with low pump capacities. Based on

4 and 5, the new pneumatic bistable switch will be described in more detail.

In Fig. 4a, the bistable jump mechanism is denoted by 77 and the two pneumatic three-way valves with 78 and 79. The control gas enters the valves through the pipes 80 and 81 and via the Valve tubes 82 and 83 in the left and right diaphragm chamber of the connected Duplex pump. 84 and 85 are ventilation openings, 86 and 87 are lever arms which are pivotably mounted at points 88 and 89 are. Both lever arms are over the BübersJ. 90 thereby a joint connected to the jump mechanism. 91 is a preloaded, for example Leaf spring loaded with a force of 200 ρ. The bias takes place in that it is shown in FIG. 4b with its Back on the carriage 95 to the housing 97 with 200 ρ and supported

• i

exerts a reaction force of 100 ρ on each of the levers 86 and 87 via the bracket 90a. If a force of more than 200 p acts on the plunger 96, it is moved downwards with the slide 95 and the spring 91 is loaded with more than 200 ρ. (The load in slide 95

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109883/0310 * "BATH

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The sensitive spring is tensioned with about 500 ρ and should only have a dampening effect if very hard blows with more than 500 ρ are applied to the plunger 96). The spring 91 is bent downwards and jumps at about 230 ρ into the position shown in FIG. 4b and shown in side view in FIG. 4b. In this case, at the same time in Fig. 4a moves the bracket 903 from the dashed position abruptly in air extended position, and the levers 86 and 87 switch over. As can be seen from the elevation 4b or the associated side elevation 4d, the leaf spring 91 in the new position is in contact with the carriage 92. This has the consequence that the carriage moves from the position shown in FIG. 4c into that of FIG. 4d moves. In the process, the spring 93 is loaded against the housing 97 with a force which, in the given example, is 200 ρ and is transmitted to the bracket 90 via the leaf spring 91.

Now acts on the plunger 98 in the direction of that shown in FIG. 4d If a force is applied by the arrow, the slide 92 is moved upwards, supported by the spring force 93, and the leaf spring 91 bent upwards. At a load of about 230 ρ, it jumps into the position shown in solid lines in FIG. 4b and shown in FIG. 4c * around. At the same time, bracket 90a and the carriage 95 jump returned to the starting position, and the leaf spring 91 with the already mentioned force of 200 ρ. By pressing on the plunger 96, the leaf spring is made to jump over again and a new switching process is initiated. Just like in the sled

A damping spring can also be fitted in the slide 92.

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109883/0310 ORIGINAL BATHROOM

PLA 68/1220

For pumps with very low piston speeds, the Damping springs can also be dispensed with.

In Fig. 5, the bistable double switch described above is used to control a duplex pump. The pump should do this be operated with a gas of about 10 atü, for example with the flushing gas from a palladium-silver diffusion cell. The pressure from 10 atm makes the installation of the two circuit breakers 101 and 102 necessary. The quantity regulation takes place in the way, that the pump and control elements are housed in a vessel 103, in which the pressure depends on the connected Consumers are continuously changing. The vessel 103 serves at the same time as a storage container for the connected consumer, in the embodiment of FIG. 5 to supply the gas burner of the Reformers. The effective areas of the pump diaphragms are here dimensioned so that the pump shows its maximum output at about 0.1 atmospheric pressure in the vessel 103 and comes to a standstill at a pressure of 1.0 atmospheric pressure comes.

The gas mixture generated in the reformer is used to remove the COp passed through a palladium-silver diffusion cell. This here Gas escaping from the Pd-Ag diffusion cell that enters the burners of the reformer is to be supplied with 0.05 atmospheric pressure, the LS 101 is first supplied as the working gas with its pressure via the lines 104 and 105 and fed via line 106 to LS 102. Purge gas flows simultaneously from line 104 via line 107,

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the pressure reducer 108, which reduces the pressure of the spill gas to the usual control pressure of 1.4 atmospheres, and the lines 109 and 110 to the three-way valve 111 of the two-way switch. Furthermore, gas flows from line 112 to three-way valve 113. In the position shown, three-way valve 113 is open for the control gas, so that it passes through this valve and line 114 into the membrane chamber of LS 102 and switches it over. This clears the path for the working gas in line 106 to flow through LS 102 and line 115 into the left diaphragm space of pump 116. The working diaphragm is loaded with pressure and the diaphragms and shift rods move to the right. The right diaphragm space of the pump 116 is vented at this point in time via line 117 and LS 101. The movement of the pump diaphragm to the right is ended when the left switching rod of the pump touches the bistable double switch and the leaf spring 118 of the spring mechanism and thus three-way valve 113 in..die--. position shown in dashed lines switches. Thus, the supply of the control gas from line 112 in line 114 through the three-way valve 113 is blocked; Line 114 and membrane space of LS 102 are vented via three-way valve 113. As a result of the spring force characterized effective M of LS 102, a changeover takes place this switch in the position shown. The exit of the working gas from line 106 is blocked and the left diaphragm chamber of the pump is vented via line 115 and LS 102. With the previously mentioned switchover of the three-way valve 113 and the jumping of the leaf spring 118, the switchover of the three-way valve 111 * into the position shown in dashed lines takes place at the same time. So that is the way of the

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BADOfMQtNAL

Control gas in line 110 released through three-way valve 111 in Line 119 and the membrane space of LS 101 where the LS is switched by the control pressure. The working gas from line 105 now flows through LS 101 via line 117 into the right, Diaphragm chamber of the pump, pressurizes the working diaphragm of the pump with pressure and moves the pump diaphragms and shift gas linkage to the left. This movement is maintained until the right one The switch rod of the pump touches the bistable switch and switches it over via the leaf spring 118 so that it is again in the extended position. A new work cycle can then begin.

The feed of the fuel to be conveyed into the reformer, for example a mixture of methanol and water in a molar ratio of -J: 1 takes place in FIG. 5 via the pipe 120 and the outlet via the Tube 121. The line 123, which is provided with a pressure reducer 122, is used to remove gas for heating the reformer certain gas burner.

The circuit breakers 101 and 102 shown in FIG. 5 can then be omitted when the gas used for work has a pressure of 1.5 atmospheres. The duplex pump also comes to a standstill at 1.0 atm in the vessel & 33

about 0.6 atü back pressure reaches its maximum pumping »because of the for the fuel cell ensures the required pre-pressure of the Hp of 0.5 atü have to be.

Such an arrangement is shown in FIG. The working

- ¹⁶ - 1 0 9883/03 10 ^{By / Or}

BAO

PLA 68/1220

4?

gas, for example hydrogen obtained by reforming and purified by lye washing, is fed via line 131 to the duplex pump 132 and fed via line 133 or 135 to the three-way valve 134 or 136. In the drawn position, the three-way valve 136 is open and the hydrogen flows via line 137 into the right diaphragm chamber of the pump 132. The pressure of the hydrogen is applied to the working diaphragm and consequently moves to the left with the other diaphragms and switching rods. The left diaphragm space of the pump is vented here via M line 138 and three-way valve 134. The movement is ended when the right switching rod touches the spring mechanism 139 of the bistable double switch and this switches over to the position shown in dashed lines. The right diaphragm space is thus vented via line and three-way valve 136, the left diaphragm space of the pump is filled with the hydrogen gas present in line 133 via three-way valve 134 and line 138, and pump diaphragms and rods are again moved to the right. The movement is terminated when the left switch rod of the pump touches the spring mechanism 139 of the bistable switch and switches it to the position shown in full line.

The hydrogen leaves the vessel 142 via the valve 145 and flows through the pressure reducer 140 and line 141 into the fuel battery, which has not been drawn in for the sake of clarity. The feed of the hydrogen-containing substance into the pump takes place via line 143 and the feed line into the reformer line 144.

109883/0310

The one in Pig. 6 embodiment shown can according to the invention can also be improved in such a way that the three-way valves 134 and 136 sit directly on the pump housing or built in will. This allows lines 137 and 138 to be omitted and the harmful spaces (dead volume) are reduced.

According to a further embodiment of the invention, the bistable Jump mechanism can also be equipped with pressure-relieving valves. The main advantage of this is that the valve covers are closed with the same force on both the pressure side and the exhaust side will. By relieving the pressure on the three-way valves can now be used as Control gas, a working gas with a higher pressure, e.g. up to 10 atu, can also be used, i.e. power valves are not required up to a pressure of 10 atu.

Pig. 7 shows a bistable four-way switch for operating two synchronously running pumps, in which the bistable spring mechanism 150 with the four pressure-relieved three-way valves 1S1, 152, 153 and 154 is combined. By pressing the plunger 155, as shown in Fig.

6, the leaf spring 156 and the bracket 157 to jump over brought. The valve carriers 158, 159, 160 and 161 are guided down into the position shown. The vents and 163 are closed by means of the valve balls 151 and 154 ^ and Working gas or gas flows through openings 164, 165, 166 and 167. Steam into the membrane spaces of the connected pumps. Are there

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ORtGlNAL

PLA 68/1220

the vents 168 and 169 released so that the Working gas through openings 170 and 171 from the work rooms the pumps can flow out. The ball valves 15? ^ nd 153 close the valve chambers and thus prevent the inflow of the working gas via the openings 172 173.

When the end position of the pumps is reached, the plunger 178 if a pressure is exerted, the leaf spring and bracket jump over and the valve carriers are moved in the opposite direction. This releases the vents 162 and 163 and the working gas flows out of the membrane spaces through openings 165 and 166 the pumps so that venting takes place. Simultaneously

the openings 172 and 173 via feeder 170 and 171, for the entry of the working gas into the diaphragm chambers of the pump is released and the piston rods of the pumps are in the opposite direction Sighting moves. The vents 168 and 169 are closed, so that the working gas is prevented from escaping here will. . .

The pressure relief of the valve seat, known per se, comes about in the embodiment shown in FIG. 7 as follows: In the supply lines 164 and 166, the working gas is under a predetermined pressure and acts in accordance with the diameter of the valve opening with a force on the valve balls. As the seals 179, 180, 181 and 182 on the other hand have the same "diameter

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8AD QftfGINAL 109 8 83/0310

TLA 68/1220

like the valve openings, the same force acts on the valve balls and seals, but offset by 180.

The valve supports according to the invention preferably consist of a metal rod and are provided with a collar. The spherical Valves can be made of known plastics, e.g. multi-component glue or epoxy resin, and are formed with the help of spherical domes made of glass or Teflon and applied to the valve support. In this case, the valve balls made of plastics are expediently tubular extended. So that they encompass the metal axes and geren the axis are pressed by the pending gas pressure.

The pumps according to the invention are particularly suitable for pumping and metering smaller amounts of liquid, for example liquid fuels or oxidizing agents in fuel elements or in a reformer of a fuel cell system. Can also Circulation of the electrolyte or de3 coolant in fuel elements by means of the new differential pump. Both that from the differential pump can be used as the control and working gas of the differential pump Pd-Ag diffusion cell as well as the purge gas exiting the reformer escaping gas can be used. Furthermore, for loading. drove the differential pump stored gas in pressure bottles, for example hydrogen or oxygen can be used.

27 claims
7 figures

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t 09 8 8 3 / Q310

BAD OWGlNAt

Claims (1)

Claims PLA 68/1220 1) Valve-controlled differential pump for pumping and metering liquids, especially for pumping and metering of liquids in fuel cell units, characterized in that the control elements of the pump are made mechanically and pneumatically or mechanically operated three-way valves. 2. Differential pump according to claim 1, characterized in that the mechanically operated three-way valves with a mono or bistable jump mechanism are combined. 3 *. Differential pump according to claim 2, characterized in that the monostable spring mechanism consists of a leaf spring (72a) and a U-spring (72b) which closes or opens the opening (74) or (75) via a switching lever (73). ^ 4. Differential pump according to claim 3, characterized in that the monostable m overcentre of a leaf spring and a U-spring is made, the shift lever 2, the openings of two three-way / valves simultaneously closes or opens. 5. Differential pump according to claim 2, characterized in that the bistable spring mechanism (77) consists of a pretensioned leaf spring ("91), which is connected to the bracket (90) via two joints. - 21 - By / Or 109883/0310 PLA 68/1220 is bound and rests on the carriage (95) or (93) and that the bracket (90) with two levers (86) and (87) for simultaneous Switching is provided by at least 2 three-way valves. 6. differential pump according to claim 5, characterized in that with the bracket (90,157) at least two valve carriers (158,159, 160,161) are connected in a tension and compression force fit, the at least two pressure-relieved three-way valves (151,152,153,154) switch at the same time. · 7. The method for operating the differential pump according to claim 1, characterized characterized in that the working gas of the pump operated mechanically and pneumatically or mechanically via one or two Three-way valves is fed. 8. The method according to claim 7, characterized in that the pump (1.49) the working gas via pneumatically operated circuit breaker (8,35,37) is supplied, the pressure of the gas used for control prior to introduction into the three-way valves (6,7,9,10,11,4-0,43,44,55,46,48) is reduced via a pressure reducer (15,38). • 9. Method according to claim 7, characterized in that the Simplex pump (1) with at least one pneumatic three-way valve (8) and the duplex pump (49) with at least two pneumatic actuated three-way valves (35,37) is controlled. 109883/0310 _B y / 0r OWGlNAL PLA 68/1220 Il 10. The method according to claims 7 to 9, characterized in that that the power of the pump via a needle valve (13,32) and / or. is regulated via the gas pressure in the container (29,68,103). 11. The method according to claims 7 to 10, characterized in that that the mechanically operated three-way valves (6,7,46,48) are driven with a monostable spring mechanism. 12. The method according to claims 7 to 10, characterized in that M that the mechanically operated three-way valves (78,79) are driven by a bistable spring mechanism (77). 13. The method according to claim 12, characterized in that the bistable spring mechanism (150) switches 2 to 4 pressure-relieved three-way valves (151,152,153,154) at the same time. - 14. The method according to claims 12 and 13 »characterized in that the plungers (94,96) are actuated alternately in opposite directions corresponding to the pump strokes, the sheet M The spring (91), the bracket (90) and the levers (86) and (87) attached to the bracket in the spring mechanism each jump in the opposite direction, so that either the valve tubes (81.) and (85) or the valve tubes (80) and (84) / 4> between ^C. g ^^ iet be. 15. The method according to claims 12 to 14, characterized in that the plunger (96) with axial movement, over a given - 23 - By / Or 109883/0310 PLA 68/1220 if a spring-damped slide (95), a leaf spring (91), which is supported on this with a predetermined force, bends until it jumps around and with the predetermined Force acts on a counter spring (93) via the slide (92), so that the leaf spring moves the bracket (90) in the opposite direction and the levers (86) and (87) switch over abruptly. 16. The method according to claims 12 to 14, characterized in that W that upon movement of the plunger (98) this so long the carriage (92) on which the leaf spring (91) is supported with the predetermined force, pushes., Until the biased leaf spring jumps around and thus moves the bracket (90) in the opposite direction, so that the levers (86, 87) switch back to the starting position. 17. The method according to claims 12 to 16, characterized in that that the bracket (90) serving to support the leaf spring (91) is firmly connected to a second bracket (90a), the power transmission to the levers (86,87) of the Breiwegeventile takes place exclusively via the bracket (90a). 18. The method according to claims 12 to 15, characterized in that that the force of the leaf spring (156) on the bracket (157) on the Veetic axles (158,159,160 and 161) of the pressure-relieved ball valves (151,152,153 and 154} is transmitted. - 24 - "By / Or 49 PLA 68/1220 is; ■; ^:: - 19. The method according to claim 18, characterized in that the force of the leaf spring (T56) on the bracket (157) on the off Metal best valve shafts of the pressure-relieved ball valves is transferred, the possibly lengthened The balls of the valves (151,152,153,154) are made of plastic and are glued to the metal axles. ν 20. The method according to claims 7 to 19, characterized in that that the differential pump for the delivery and metering of the fuel elements to be converted fuel or oxidizing agent is used. . 21. The method according to claims 7 to 19, characterized in that that the differential pump for pumping and metering the hydrogen-containing compounds used to generate hydrogen is used in the reformer of a fuel cell system. 22. The method according to claims 7 to 19 ». Characterized in that Jj that the differential pump is used to circulate electrolyte in fuel elements. ■ ■■ »■ '. 23. The method according to claims 7 to 19 »characterized in that that the differential pump is used for coolant circulation. 24. The method according to claims 7 to 23, characterized in that that the purging gas emerging from the Pd-Ag diffusion part is used as the control and working gas of the differential pump. original INSPHCTED 10 9 8 8 3/0310 - 25 - ■ By / Or -PIA 68/1220 J * 25. The method according to claim ^, characterized in that the pump unit is placed in a gas-tight container and that for the control and operation of the differential pump The gas used is then used to heat the reformer. 26. The method according to claims 7 to 23, characterized in that that the gas emerging from the reformer is used as the control and working gas of the differential pump. . 27. The method according to claims 7 to 23, characterized in that that the control and working gas provided for the operation of the fuel elements and stored in drain bottles, for example hydrogen and / or oxygen is used. - 26 - 10 9 8 8 3/0310 By / Or 5? Blank page