Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K17/00—Safety valves; Equalising valves, e.g. pressure relief valves
  • F16K17/02—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side
  • F16K17/04—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side spring-loaded
  • F16K17/0473—Multiple-way safety valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D15/00—Control, e.g. regulation, of pumps, pumping installations or systems
  • F04D15/0005—Control, e.g. regulation, of pumps, pumping installations or systems by using valves
  • F04D15/0011—Control, e.g. regulation, of pumps, pumping installations or systems by using valves by-pass valves

Definitions

• the oresent invention relates to an automatic recirculati valve intended for use in installations where a least flow required for protecting such as centrifugal pumps.
• valve accordance with the present invention automatically achieves recirculation flow.
• the valve constitutes a self-regulati system, which eliminates the need of external sensors, r gulating means and supplied energy.
• the valve in accordance with the invention offers fo functions in a compact valve, namely that it is flow-sensin that it regulates the amount of flow passing through, that regulates the pressure of the passing flow and that it has check valve function.
• the valve thus affords a plurality properties which are not to be found all together in valves this type at present on the market.
• An automatic recirculati valve should have the following properties: The provision reliable pump protection, low energy consumption, low i stallation cost, small service requirements and short settin adaption times.
• the valve of the present invention has many advantages, o which may be mentioned a modulated flow, which agrees with th characteristic of the pump used, thus eliminating energy losse accompanying conventional "stop-and-start" systems. Pins an linkages are no longer needed to achieve a modulated flow, an the inventive valve has only one moving part, namely a chec valve inside the valve housing. What is particularl distinguishing for the present invention is that it has a least two pressure reducing stages for avoiding flashing cavitation and pitting problems. The pressure reducing stage are built in inside the valve housing, and the number of stage can be selected to suit the required pressure reduction. Six or more stages may be usual for high pressure drops.
• the automatic recirculation valve is constructed such that a bypass flow is ensured for a low load state.
• the sole patt wxiich can break down in the valve according to the present invention is a spring included in i*-. Eve if this spring should malfunction, the check valve clo es at low pump flow, v ⁇ hich means _hat the pump protection is maintained.
• its inner parts are accommodated in an exchangeable holder. All these inner parts, namely the check valve, guides, pressure reduction section and the spring are included in the holder which can be easily dismantled from the valve for main ⁇ tenance. This permits simple maintenance on site.
• valve plunger has a high natural frequency to avoid water hammering.
• the natural frequency of the valve will be higher than 5 Hz, which ensures good adaptability to the flow changes in the piping system in question, which eliminates the sensitivity of the valve to surges in the flow.
• the inventive valve is thus a flexible valve, which can be fitted to the pump outlet, vertically or horizontally, and which may be used for a variety of different liquids, from the feed water for a boiler to oil, hydrocarbons and low temperature liquids.
• a typical temperature range is from -73° to 20 °C and higher, depending on the application in question.
• Fig. 1 illustrates a cross-sectional view of a valve in accordance with the present invention.
• Fig. 2 is a schematic depiction of a conventional system
• Fig. 3 is a schematic depiction of a system including the valve in accordance with the present invention.
• the valve according to a preferre embodiment of the present invention includes a valve housin 13, in which there is a plunger 12 functioning as a chec valve.
• the plunger 12 is controlled by a main flow coming int che valve through an inlet 15.' ⁇ nd is also rentrolled by spring 2.
• the plunger 12 is arranged inside the housing 13 suc as to slide in a plunger guide sleeve 9 mounted in a plunge holder 8.
• the plunger In the guide sleeve 9 the plunger is displaceabl against the bias of the spring 2 from a first position an successively to a second position.
• th free end 16 of the plunger seals against a valve seat 14 although a part of the main flow, i.e. the least permissibl flow for a circulation pump, can flow into a central bore 17 i the plunger 12, out from this bore via holes 18 in the cylin drical surface of the plunger, and further out through a bypas tube 7 via orifices 19-23 and circumferential recesses 24 i the sleeve and circumferential recesses 25 in the plunger.
• Thi first position changes successively into a second positio where the orifices 19-23 in the guide sleeve 9 are completel blocked by the circumferential surface of the plunger 12 s that a main flow can freely stream round and past the free en 16 of the plunger straight through the valve.
• the bypass flo which streams through the valve when it is closed and ou through the bypass tube 7 is intended, as mentioned, to provid protection against a centrifugal pump seizing when it work against a shut off main flow.
• the spring 2 is compressed be ⁇ tween one end of the plunger 12 and a cap 1, fastened to the plunger holder 8 with the aid of screws 3.
• the bypass tube 7 is fixed in a radial bore in the plunger holder 8 and is sealed against it by an O-ring 5. At its outlet opening the tube 7 has a flange which is sealed against the housing 13 by a gasket 6.
• the plunger guide sleeve 9 is formed as a cylindrical sleeve and abuts, via a gasket 4, against an inwardly directed flange at the downstream end of the plunger guide 8.
• the plunger guide sleeve 9 is provided with at least two circum ⁇ ferential flanges 26 at given mutual spacing, which are sealed against the plunger holder 8 with the aid of O-rings 10.
• the valve in accordance with the invention has at least two pressure-reducing stages, where the number of these stages can be selected to suit the desired pressure reduction.
• the pressure reducing stages comprise at least two successively arranged variable constriction stations between the plunger 12 and guide sleeve 9.
• the guide sleeve 9 has three variable constriction stations denoted by A,B and C.
• These stations comprise orifices 19,20 and 22 in the circumferential surface of the guide sleeve, where the orifices 19 are arranged round the circumferential surface of the guide sleeve so that alternate orifices 19 are somewhat displaced relative the others, and the remaining orifices 20, 22 are arranged round the circumference of the sleeve 9 in a similar manner.
• the orifices 19, 22 open out into the most upstream circumferential recess 24 in the sleeve 9, as seen in Fig. I, this recess being formed between the flanges 26 on the guide sleeve 9 and defined outwardly by the wall of the plunger holder 8.
• the orifices 20 open out into the circumferential recess 25 in the cylindrical surface of the plunger 12 and which extends- up to the orifices 21 arranged in the circumference of the guide 9, so that the bypass flow enters a second circumferential recess 24 in the sleeve, the flow going from this recess into the third constriction station C via the orifices 22 in the sleeve 9, from whence the flow streams out into the bypass tube 7 via a second circumferential recess i the plunger 12 and orifices 23 in the guide sleeve 9.
• Fig. 2 there is illustrated a conventional system which i often u?e ⁇ ] today with '-ei ifjgal i for providing a bypas flow
• Fig. 3 there is illustrated an installation i which the valve in accordance with the present invention i and by attends to flow sensing- pressur reduction and control of the modulated flow quantity.
• Th inventive valve functions such that when the valve to th process is closed, the plunger 12 is urged upstream (to th left in Fig. 1) with the aid of the spring bias in the spring and into engagement against the seat 14 in the valve housin 13.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Safety Valves (AREA)
• Lift Valve (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20365904

Family Applications (1)

Country Status (2)

Cited By (4)

Citations (1)

• 1986
  • 1986-10-10 SE SE8604328A patent/SE454619B/sv not_active IP Right Cessation
• 1987
  • 1987-10-09 WO PCT/SE1987/000459 patent/WO1988002831A1/en unknown

Patent Citations (1)

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