Patent GB-802763-A (GB)
Title: Improvements relating to fluid-metering devices
IPC: G05D11/00
Filed: 1956-08-03
Abstract: 802,763. Mixing fluids in flow. MEDOAPPARATEGESELLSCHAFT M.B.H. & CO. Aug. 3, 1956 [Aug. 4, 1955, Dec. 15, 1955], No. 23956/56. Class 86 Apparatus for introducing a fluid contained in a chamber 15 into a fluid flowing under pressure through a pipe 1 in proportions dependent upon the rate of flow of the pressure fluid comprises a rotor 3, driven by the pressure fluid, which actuates a control valve 5 which admits pressure fluid to the interior of a metal bellows 11 disposed in the chamber 15 and a valve 8 which reduces the pressure of the fluid in the pipe 1 so that on the admission of high pressure fluid to the interior of the bellows 11 the latter expands and forces fluid from the space surrounding the bellows through a passage 16 into the pressure fluid flowing through the pipe 1 on the low pressure side of the valve 8. The rotor 3, through step by step intermittent gearing 4, drives the control ring 5 through 180 degrees, thereby closing and opening an aperture 6 leading through a passage 13 to the interior of the bellows 11. Through a compensating passage 14, the connecting passage 13 is in communication with zone 7 of low pressure. On the end face 17 of bellows 11 is mounted a piston 19 slidably received in a bore 20 connecting with a fluid supply conduit 21 having non return valves 22, 23. The conduit 20 leads to a reservoir 24 which contains the fluid to be introduced into the system. The stroke of piston 19 and diaphragm 17 is limited at its upper end by a screw 25 and at its lower end by a pin 26. To give pressure compensation two different bellows 27, 28 are provided. The bellows 28 may contain fluid which indicates, via a passage 29, the functioning of the apparatus in a sight glass 30. A second embodiment comprises pipe section 1<SP>1</SP>, Fig. 2, with rotor 3<SP>1</SP> control ring 5<SP>1</SP> and pressure reducing valve 8<SP>1</SP>. A housing 33 bolted to the pipe section has a sieve plate 34 adapted to support substances to be dissolved in the fluid contained in the housing 33. An expansible pressure chamber 37 is connected to an opening 6<SP>1</SP> through a pipe 36. A set screw 39 limits the stroke of chamber 37. The interior of tube 36 communicates with zone 7<SP>1</SP> through a passage 41. A non return valve is installed in a passage 42. The passage 45 communicates with a riser tube 46 having a valve 47. Through these passages, space 38 is connected with zone 7<SP>1</SP>. A filler neck 48 serves for inserting the chemicals 35. In a further embodiment, shown in Fig. 3, a rotor 3<SP>11</SP> through gearing 4<SP>11</SP> drives the control ring 5<SP>11</SP> located in a chamber 51 which is in communication with a passage 52 leading to a high presure zone 2<SP>11</SP>, with a passage 53 leading to a low pressure zone 7<SP>11</SP> and a passage 54 leading to a pressure chamber 12 which is closed by an elastic membrane 55. The passages 52 and 53 are periodically uncovered and closed by a ring 5<SP>11</SP>, so that higher and lower pressures alternate in the chambers 51 and 12. Depending on the pressure conditions in chambers 51 and 12, the membrane 55 changes its position thereby actuating a control slide valve 56 connected to it. The valve 56 controls the admission of fluid to a chamber 63 formed by a membrane 64 attached to the upper end of a bellows 68. On the upstroke the bellows draws additive fluid from a reservoir 73 and on the downstroke the fluid is supplied through a conduit 71 to the fluid under pressure flowing through the pipe 1<SP>11</SP>.