Pump assembly

Abstract

A pump assembly includes a housing having two parts with internal cylindrical chambers having openings for the inlet and outlet of a pumped fluid, and two longitudinally deformable bellows fastened inside the respective parts of the housing. The opposite end of each bellows has a plug. On the end surface of the housing the bellows are connected to is an opening for the inlet of a working fluid into the corresponding internal chamber. A hydraulic system for controlling the pump assembly includes a tank containing a working fluid, a positive displacement pump, two independent hydraulic pipelines, and a system of valves for alternately connecting the bellows' internal chambers containing working fluid to the pipelines. The internal chamber of each bellows is alternatingly connected to the positive displacement pump for supplying working fluid by a first hydraulic pipeline and to the working fluid tank by a second hydraulic pipeline.

Claims

1. A pumping assembly, comprising a housing consisting of at least two parts with internal cylindrical chambers and having holes for supplying and discharging of a pumped fluid; at least two longitudinally deformable bellows attached with one end surface to each part of the housing from inside, an opposite end side of each bellows being closed with a plug, while the end surface of each part of the housing connected with the bellows having a hole for supplying a working fluid to an internal chamber restricted by the bellows, its plug and the end surface of the part of the housing; and a pumping assembly hydraulic control system, wherein the pumping assembly hydraulic control system comprises: a tank containing the working fluid; a force pump; two or more independent hydraulic lines; and a valve system configured to alternately connect internal chambers of bellows to a first or second line depending on positions of the bellows, the hydraulic lines being designed in such a way that working fluid pressure in the first line is below than a pumped fluid inlet pressure and working fluid pressure in the second line is higher than the pumped fluid inlet pressure; wherein the internal chamber of each bellows is connected to the said hydraulic lines in such a way to alternatively switching between the force pump for supplying the working fluid via the first hydraulic line and the tank containing the working fluid via the second hydraulic line, and wherein the pumping assembly further comprises a means for tracing position of each bellows being configured to control alternate connection of the internal chamber of each bellows to the first or second hydraulic line depending on the bellows position.

2. The pumping assembly according to claim 1, wherein the means for tracing position of each bellows is installed in the internal chamber of the bellows and comprises a fixed tube and a rod, one end of the rod being attached to the bellows plug and the other end being loosely inserted in the fixed tube attached to a surface opposite to the bellows plug, while rod position transducers are installed on the fixed tube at a distance of a bellows stroke.

3. The pumping assembly according to claim 1, wherein a pump is additionally installed on the second hydraulic line for pumping the working medium into the tank.

4. The pumping assembly according to claim 1, wherein the means for tracing position of each bellows is installed in the internal chamber of the bellows and comprises a position transducer, a rod and a tube, one end of the rod being attached to the bellows plug and the other end being loosely inserted in the tube attached to a surface opposite to the bellows plug, while the rod has marks to control position of the rod.

5. The pumping assembly according to claim 1, wherein the means for tracing position of each bellows is installed in the internal chamber of the bellows and comprises a position transducer, a revolvable spool, and a cable wound around the spool, the spool being attached to a surface opposite to the bellows plug, while one end of the cable is fixed on the plug.

6. The pumping assembly according to claim 1, wherein the means for tracing position of each bellows comprises a rotation speed sensor mounted on the force pump and designed to monitor filling of the internal chamber of the bellows by determining working medium volume necessary to fill the internal chamber of the bellows.

7. The pumping assembly according to claim 1, wherein holes for supplying and discharging the pumped medium are made in a lower and/or upper part of the housing.

8. The pumping assembly according to claim 1, wherein the bellows is made as a composite of individual elastic membranes connected in series with each other by end surfaces.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) These and other features and advantages of the invention will become better understood when considered in conjunction with the following detailed description and by referring to the appended drawings, wherein:

(2) FIG. 1 is a general view of the pumping assembly.

(3) FIG. 2 is a view of rod and position monitoring transducers.

(4) FIG. 3 is a view of limit switch.

(5) FIG. 4 is a view of a pumping assembly according to one embodiment with an additional group of housings with cylindrical chambers.

(6) FIG. 5 is a view of working fluid control system in a pumping assembly according to one embodiment of the invention.

(7) FIG. 6 is a view of working fluid control system in a pumping assembly according to another embodiment of the invention.

(8) FIG. 7 is a view of working fluid control system based on a system of hydraulic locks with electromagnetic control in a pumping assembly according to another embodiment of the invention.

(9) FIG. 8 is a view of one embodiment of bellows position control system.

(10) FIG. 9 is a view of another embodiment of bellows position control system.

(11) Numbers in the drawings indicate the following items:

(12) 1—first part of housing; 2—bellows; 3—suction valve; 4—discharge valve; 5—force pump; 6—draw-off pump; 7—discharge pressure control hydraulic distributor; 8—hydraulic distributor; 9—pilot-operated valve; 10—tank with a working fluid; 11—second part of housing; 12—second bellows; 13—suction valve; 14—discharge valve; 15—plug of the first bellows; 16—hydraulic control system of pumping assembly; 17—discharge line; 18—suction line; 19—pilot-operated valve; 20—first hydraulic line; 21—second hydraulic line; 22—transducer of lower position; 23—rod; 24—tube; 25—pumped fluid; 26—working fluid; 27—plug of the second bellows; 28—rod; 29—limit switch; 30—limit switch; 31—transducer of upper position; 32—valve; 33—valve; 34—valve; 35—valve; 36—hydraulic distributor; 37—hydraulic distributor; 38—hydraulic distributor; 39—hydraulic distributor; 40—control pump; 41—control line; 42—hydraulic lock; 43—hydraulic lock; 44—hydraulic lock; 45—hydraulic lock; 46—sensor; 47—sensor; 48—spool; 49—spool; 50—rotation speed sensor.

(13) Besides, letters “a” and “b” indicate positions of hydraulic distributor for the force line control (7) while letters “c” and “d” show similar positions of hydraulic distributor (8).

DETAILED DESCRIPTION OF THE INVENTION

(14) Pumping assembly (FIG. 1) comprises a housing consisting of at least two parts (1) and (11), each part (1) and (11) of the pumping assembly housing having a cylindrical internal chamber. Bellows (2) and (12) are installed inside each of said housing parts (1) and (11) of the pumping assembly housing. These bellows (2) and (12) are mounted on inner upper or lower end surface of each housing part (1) and (11) of the pumping assembly housing, respectively.

(15) Each bellows (2) and (12) is closed in its free end with a plug (15) or (27), respectively. The chamber, formed by bellows (2) or (12), mounted on end surface of housing part (1) or (11) of the pumping assembly housing, and its plug (15) or (27), closing free end of bellows (2) or (12), respectively, is referred as the inner chamber of bellows (2) or (12). Bellows (2) and (12) with plugs installed inside parts (1) and (11) of the pumping assembly housing separate the working fluid (26) occurring in inner chambers of bellows (2) and (12) from the pumped fluid (25) occurring outside the bellows (2) and (12) in the same chambers of parts (1) and (11) of the pumping assembly housing.

(16) Each part (1) or (11) of the pumping assembly housing has inlet or outlet port (holes 100a1-100a2 and 100b1-100b2) suitable to connect the suction line (18) or discharge line (17), respectively. A discharge valve (4) or (14) is installed on the discharge line (17) of the pumped fluid (25). A suction valve (3) or (13) is installed on the suction line (18) of the pumped fluid.

(17) The pumping assembly further comprises a pumping assembly hydraulic control system (16), in turn comprising a tank (10) containing the working fluid; a force pump (5); two or more independent hydraulic lines (20) and (21), and a valve system.

(18) The pumping assembly operation hydraulic control system (16) consists of two independent hydraulic lines (20) and (21).

(19) The first hydraulic line (20) is under pressure higher than the pumped fluid (25) inlet pressure in the suction line (18).

(20) The second hydraulic line (21) is under pressure lower than the pumped fluid (25) inlet pressure in the suction line (18).

(21) The first hydraulic line (20) of the pumping assembly control line (16) connects each bellows (2) and (12) with discharge pump (5) to supply the working fluid (26), the discharge pump being a component of the pumping assembly. The connection of each bellows (2) and (12) with discharge pump (5) is governed by a discharge pressure control hydraulic distributor (7) installed on the first hydraulic line (20). The discharge pressure control hydraulic distributor (7) is designed to distribute supplied working fluid (26) among said bellows (2) and (12). The first hydraulic line (20) of the pumping assembly control line (16) also connects the pump (5) designed for supplying the working fluid (26) with the tank (10) containing the working fluid.

(22) At the same time, the first hydraulic line (20) connects the pump (5), designed for supplying the working fluid (26) to each bellows (2) and (12), with the hydraulic distributor (8) designed to unlock or lock the pilot-operated valve (9) or (19). The pilot-operated valves (9) and (19) are installed at junctions of respectively first and second hydraulic lines (20) and (21) of the control line (16).

(23) The second hydraulic line (21) of the control line (16) connects each bellows (2) and (12) with draw-off pump (6) designed to pump off the working fluid (26), the draw-off pump being a component of the pumping assembly. The second hydraulic line (21) also connects the pump (6), designed to pump off the working fluid (26), with the tank (10) containing the working fluid.

(24) Operating cycle of whole pumping assembly (FIG. 1) may be divided into two stages depending on position (c) or (d) of the discharge pressure control hydraulic distributor (7).

(25) When the discharge pressure control hydraulic distributor (7) is in its initial position (c), the pumping assembly operates as follows:

(26) Pumped fluid (25) enters the suction line (18). The discharge pressure control hydraulic distributor (7) switches to position (c) and simultaneously hydraulic distributor (8) switches to position (b), thereby causing opening of pilot-operated valve (19) and closing of pilot-operated valve (9). The force pump (5) and draw-off pump (6) ensure circulation of working fluid (26) in the control line (16) of the pumping assembly.

(27) As a result of above actions, draw-off pump (6) begins to draw off working fluid (26) from inner chamber of the second plugged bellows (12) into tank (10), while the force pump (5) begins to supply the working fluid into inner chamber of plugged bellows (12) from the tank (10). Removal of working fluid (26) from inner chamber of the second bellows (12) closed with a plug (27) in its free end creates underpressure in pumped fluid inside the second housing part (11), thereby opening suction valve (13) and closing the discharge valve (14) on the pumped fluid line. This underpressure causes filling of second housing part (11) with the pumped fluid (25).

(28) At the same time, excessive working fluid in inner chamber of the first bellows (2) closed with a plug (15) in its free end, which is supplied by the force pump (5), creates overpressure inside the first housing part (1), thereby closing suction valve (3) and opening the discharge valve (4). As the working fluid (26) is injected into internal chamber of the first bellows (2) closed with a plug (15) in its free end, the pumped fluid is forced out into discharge line (17). Consequently, plugged bellows (2) and (12) move in anti-phase to each other.

(29) When the bellows (2) with the plug (15) reaches the extreme extended state, while the bellows (12) with the plug (27) reaches the extreme compressed state, the discharge pressure control hydraulic distributor (7) switches to position (d).

(30) When the discharge pressure control hydraulic distributor (7) is in its initial position (d), the pumping assembly operates as follows:

(31) The discharge pressure control hydraulic distributor (7) switches to position (d) and simultaneously hydraulic distributor (8) switches to position (a) thereby causing opening of pilot-operated valve (9) and closing of pilot-operated valve (19). The force pump (5) and draw-off pump (6) ensure circulation of working fluid in the control line of the pumping assembly.

(32) As a result of above actions, draw-off pump (6) begins to draw off working fluid from inner chamber of the first bellows (2) with the plug (15) into tank (10), while the force pump (5) begins to supply working fluid into inner chamber of bellows (12) with the plug (27) from the tank (10). Removal of working fluid from inner chamber of the first bellows (2) closed with a plug (15) in its free end creates underpressure in pumped fluid inside the first housing part (1), thereby opening suction valve (3) and closing the discharge valve (4). This underpressure causes filling of first housing part (1) with the pumped fluid (25).

(33) At the same time, excessive working fluid in inner chamber of the first bellows (12) closed with a plug (27) in its free end, which is supplied by the force pump (5), creates overpressure inside the first housing part (11), thereby closing suction valve (13) and opening the discharge valve (14). As the working fluid is injected into internal chamber of the second bellows (12) closed with a plug (27) in its free end, the pumped fluid (25) is forced out into discharge line (17).

(34) When the bellows (12) with the plug (27) reaches the extreme extended state, while the bellows (2) with the plug (15) reaches the extreme compressed state, the discharge pressure control hydraulic distributor (7) switches back to position (c). Then the cycle is repeated.

(35) Below are disclosed embodiments of the present invention with bellows (2) and (12) position control using either position transducers (22), (31) and rod (23) or limit switches (29) and (30).

(36) One embodiment of the claimed invention provides determining positions of bellows (2) and (12) with the aid of position transducers (22), (31) and rod (23) (FIG. 2), the rod (23) moving in tube (24) with two installed position transducers (22), (31) at a distance of bellows stroke. The rod (23) is installed in the inner chamber of each bellows (2) and (12) closed in its end part with a plug (15) or (27), respectively. The rod (23) has holes drilled in its body. One end of rod (23) is attached to the plug (15) or (27), while the other end is loosely inserted in the tube (24). Tubes (24) are fixed in each housing part (1) and (11), respectively. Rod position transducers (22) and (31) are installed on each tube (24) perpendicularly to its axis. Upper position transducers (22) are located in the upper part of each tube (24), whereas the lower position transducers (31) are located in the lower part of each tube (24). The distance between upper position transducers (22) and lower position transducers (31) must be equal or less than stroke of bellows (2) or (12) closed with plug (15) or (27), respectively. When bellows (2) or (12) is in the extreme extended state, upper end of the rod (23) must be opposite the lower position transducer (31). At this moment, the lower position transducer (31) transmits signal “bellows is extended”, which switches discharge pressure control hydraulic distributor (7) and hydraulic distributor (8). Thereafter the rod (23) starts to move up. When the rod (23) reaches the upper position transducer (22), the upper position transducer (22) transmits signal “bellows is compressed”, which switches discharge pressure control hydraulic distributor (7) and hydraulic distributor (8) again.

(37) Another embodiment of the claimed invention provides determining position of bellows with the aid of a single position transducer in combination with the rod (23), wherein the rod has two holes for position control. In this embodiment, alternate values “bellows is extended” and “bellows is compressed” are assigned to signals generated by the transducer when a hole in the rod (23) aligns with the transducer's working surface.

(38) Yet another embodiment of the claimed invention with bellows position control using limit switches (29) and (30) (FIG. 3) provides determining positions of bellows (2) and (12) closed with plugs (15) or (27) in their free ends, respectively, based on touching limit switches by the plugs. In this embodiment of the claimed invention, lower limit switches (30) are installed in lower end of each housing part (1) and (11) while upper limit switches (29) are installed in upper end of each bellows (2) and (12). When a plugged bellows (2) or (12) extends to the maximum and its plug touches the lower limit switch (30), the switch transmits signal “bellows is extended”, which switches discharge pressure control hydraulic distributor (7) and hydraulic distributor (8). Thereafter the plugged bellows (2) or (12) starts to move up. When a plugged bellows (2) or (12) reaches its extreme compressed state and its plug (15) or (27), respectively, touches the upper limit switch (29), the upper limit switch (29) transmits signal “bellows is compressed”, which switches discharge pressure control hydraulic distributor (7) and hydraulic distributor (8) back.

(39) Still another embodiment of the claimed invention (FIG. 8) provides determining positions of bellows with the aid of a cable (800a, 800b) wound on a spool (48) and (49). Spools (48) and (49) are installed in the upper parts of the pumping assembly housing parts (1) and (11), and ends of cables (800a, 800b) are fixed on plugs (15) and (27), respectively. The reciprocating movement of bellows (2) and (12) leads to unwinding and subsequent winding the cable (800a, 800b) onto each spool (48) and (49). In turn, rotational movement of spools (48) and (49) caused by displacements of bellows is detected by transducers (46) and (47). Transducers (46) and (47) may be of either contact or contactless type.

(40) Still other embodiments of the claimed invention are possible based on indirect rather than direct methods of the membrane (bellows) (2) and (12) position control. In particular, bellows position can be determined (FIG. 9) using the controlled filling of inner chambers of bellows (2) or (12) closed in their end parts with plugs (15) or (27), respectively, with a working fluid (26) supplied by a force pump (5). In this case, a rotation speed sensor (50) is mounted on the force pump (5) and used to calculate the working fluid volume required to fill the inner chamber of bellows (2) or (12) closed in its end part with plug (15) or (27), respectively.

(41) Above disclosed embodiments cannot fully cover all possible approaches to tracking position of bellows closed with a plug in its lower part.

(42) In addition, the pumping assembly may comprise more than two parts of housing. Accordingly, increase in number of housing parts causes the necessity to install a number of additional components per each additional part, namely:

(43) discharge pressure control hydraulic distributor (7)

(44) hydraulic distributor (8)

(45) housing part or parts (1) and (11)

(46) discharge valves (4), (14)

(47) suction valves (3), (13)

(48) pilot-operated valves (9), (19)

(49) Above components of the pumping assembly are interconnected via first and second hydraulic lines (20) and (21) (FIG. 4).

(50) Once more embodiment of the present invention discloses a pumping assembly (FIG. 4) that comprises a housing divided into four parts, each part having a cylindrical internal chamber. Bellows are installed inside each of said housing parts of the pumping assembly housing. Each of these bellows is attached to upper end inner surface of each housing part of the pumping assembly. Each bellows is closed with a plug at the bottom. The chamber formed by bellows mounted on upper end surface of housing part of the pumping assembly housing and its plug is referred as the inner chamber of bellows. Bellows with plugs installed inside parts of the pumping assembly housing separate the working fluid (26) occurring in inner chambers of bellows from the pumped fluid (25) occurring outside the bellows in the same chambers of parts of the pumping assembly housing.

(51) Each part of the pumping assembly housing has inlet or outlet port suitable to connect the suction line (18) or discharge line (19), respectively.

(52) Discharge valves are installed on the discharge line (17) of the pumped fluid (25). Suction valves are installed on the suction line (18) of the pumped fluid.

(53) The pumping assembly operation control line (16) consists of two independent hydraulic lines (20) and (21).

(54) The first hydraulic line (20) is under pressure higher than the pumped fluid (25) inlet pressure in the suction line (18). The second hydraulic line (21) is under pressure lower than the pumped fluid (25) inlet pressure in the suction line (18).

(55) The first hydraulic line (20) of the pumping assembly control line (16) connects each bellows with discharge pump (5) to supply the working fluid (26), the discharge pump being a component of the pumping assembly. The connection of each bellows pair with discharge pump (5) is governed by a discharge pressure control hydraulic distributor installed on the first hydraulic line (20). The discharge pressure control hydraulic distributor is designed to distribute supplied working fluid (26) among said bellows. The first hydraulic line (20) of the pumping assembly control line (16) also connects the pump (5) designed for supplying the working fluid (26) with the tank (10) containing the working fluid.

(56) At the same time, the first hydraulic line (20) connects the pump (5), designed to supply the working fluid (26) to each bellows pair, with the hydraulic distributor designed to unlock or lock the pilot-operated valves. One pilot-operated valve is installed on the second hydraulic line (21) of the control line (16).

(57) The second hydraulic line (21) of the control line (16) connects each bellows with draw-off pump (6) designed to pump off the working fluid (26), the draw-off pump being a component of the pumping assembly. The second hydraulic line (21) also connects the draw-off pump (6), designed to pump off the working fluid (26), with the tank (10) containing the working fluid.

(58) Description of Valves and Control system

(59) In order to control the pumping assembly, it is necessary to control flows of the working fluid. Such flow control is available mainly with the aid of various valves. In turn, valves can have electromagnetic, hydraulic, or pneumatic control.

(60) As FIG. 5 shows, working fluid control in the pumping assembly begins from the discharge pressure control hydraulic distributor (7). When the discharge pressure control hydraulic distributor (7) is switched to position (c), working fluid is forced into inner chamber of the first bellows (2) closed with the plug (15) in its free end part and simultaneously drawn off from inner chamber of bellows (12) closed with the plug (27) in its free end part. After completion of the half-cycle, the discharge pressure control hydraulic distributor (7) is switched to position (d), and working fluid is forced into inner chamber of the second bellows (12) closed with the plug (27) in its free end part and simultaneously drawn off from inner chamber of bellows (2) closed with the plug (15) in its free end part.

(61) Another embodiment of flow control system shown in FIG. 6 provides working fluid control using a system of valves (32), (33), (34), (35), and hydraulic distributors (36), (37), (38), (39) acting via a control line (41). The working fluid control system is driven by a control pump (40) through the control line (41), valve system (32), (33), (34), (35), and hydraulic distributors (36), (37), (38), (39).

(62) Operation of the pumping assembly (FIG. 6) is most easily understood in terms of positions of the hydraulic distributors (36), (37), (38), (39). When the hydraulic distributors (36), (37), (38), (39) are in positions (a), (b), (b), and (a), respectively, the force pump (5) supplies the working fluid to internal chamber of the first bellows (2) closed with a plug (15) in its free end. An overpressure arises inside the first housing part (1), thereby closing suction valve (3) and opening the discharge valve (4). As the working fluid is injected into internal chamber of the second bellows (2) closed with a plug (27) in its free end, the pumped fluid (25) is forced out into discharge line (17). At the same time, draw-off pump (6) begins to draw off working fluid from inner chamber of the second bellows (12) closed with plug (27) in its free end part.

(63) When the bellows (2) with the plug (15) in its free end part reaches the extreme extended state, while the bellows (12) with the plug (27) in its free end part reaches the extreme compressed state, the hydraulic distributors (36), (37), (38), (39) switch in positions (b), (a), (a), and (b). Then the cycle is mirrored.

(64) Yet another embodiment of flow control system shown in FIG. 7 provides working fluid control using a system of hydraulic locks (42), (43), (44), (45) with electromagnetic control. Operating cycle of pumping assembly with a system of electromagnetically controlled hydraulic locks (42), (43), (44), (45) may be divided depending on position of these hydraulic locks (open) or (closed).

(65) When the hydraulic locks (42), (43), (44), (45) are in positions (closed), (open), (closed), and (open), respectively, the force pump (5) supplies the working fluid to internal chamber of the first bellows (2) closed with a plug (15) in its free end. An overpressure arises inside the first housing part (1), thereby closing suction valve (3) and opening the discharge valve (4). As the working fluid is injected into internal chamber of the second bellows (2) closed with a plug (27) in its free end, the pumped fluid (25) is forced out into discharge line (17). At the same time, draw-off pump (6) begins to draw off working fluid from inner chamber of the second bellows (12) closed with plug (27) in its free end part.

(66) When the bellows (2) with the plug (15) in its free end part reaches the extreme extended state, while the bellows (12) with the plug (27) in its free end part reaches the extreme compressed state, the hydraulic locks (42), (43), (44), (45) switch in positions (open), (closed), (open), and (closed), respectively. Then the cycle is mirrored.

(67) Essential features of the claimed invention: A bellows is used as a working member. The bellows deforms longitudinally along its axis, which facilitates tracking working positions of the bellows. In addition, the bellows provides a largest possible volume change per stroke at minimal overall dimensions. The working volume changes only due to longitudinal compression or extension of the bellows. Radial tensile stresses in bellows are absent, which allows to use reinforced materials and thereby increase service life of the pumping assembly. Pumping assembly housing has both inlet and outlet ports. In embodiments of the claimed invention, inlet ports are located in the lower or upper part of the pumping assembly housing. Outlet ports in embodiments of the claimed invention are located oppositely, in the upper or lower part of the pumping assembly housing. Alternating compression and tension of the bellows is forced by alternating connection of working chamber inside the pumping assembly to hydraulic lines, one of these lines being under working fluid pressure higher than the pumped fluid inlet pressure, while another line being under pressure below the pumped fluid inlet pressure.