1. A crane, in particular an overhead crane or gantry crane, comprising: at least one crane girder that extends horizontally in a longitudinal direction, is designed as a trussed girder and comprises struts connect an upper run and a lower run together, on which girder a crane trolley having a lifting gear can be moved, wherein the struts are designed in a laminar manner, each strut comprising a main surface that extends transversely with respect to the longitudinal direction of the at least one crane girder and that at least one aperture is provided on the main surface at a first or second strut end of the struts wherein the lower run or the upper run lies against the main surface.
2. The crane of claim 1, wherein the struts are positionable in a positive-locking manner relative to the lower run or the upper run using the aperture.
3. The crane of claim 1, wherein the struts are connected to the lower run or the upper run using the aperture.
4. The crane of claim 1, wherein the struts are welded to the lower run or the upper run in the region of the aperture.
5. The crane of claim 1, wherein the lower first strut end is provided with a lower aperture against which the lower run lies, and the upper second strut end is provided with an upper aperture against which the upper run lies.
6. The crane of claim 1, wherein the upper run and the lower run each comprise at least one vertical web and the web of the upper run lies against an upper aperture and the web of the lower run lies against a lower aperture.
7. The crane of claim 1, wherein the upper run comprises two upper run profiles each having a web, or the lower run comprises two lower run profiles each having a web.
8. The crane of claim 6, wherein precisely one aperture is provided for each web.
9. The crane of claim 6, wherein the upper run comprises two of said webs having a common upper aperture and the lower run comprises two of said webs having a common lower aperture.
10. The crane of claim 1, wherein the struts comprise at least one auxiliary surface that is folded at a right angle from the main surface.
11. The crane of claim 1, wherein at least one of the apertures is formed in the shape of a slot and is arranged between the longitudinal sides of the respective main surface.
12. The crane of claim 1, wherein at least two of the apertures are formed in the shape of a shoulder and are arranged opposite one another on the longitudinal sides of the respective main surface.
13. The crane of claim 6, wherein the web of the lower run or the web of the upper run is welded to at least one longitudinal side of the corresponding aperture, which longitudinal side extends in parallel with a longitudinal axis of the struts.
14. The crane of claim 1, wherein the upper run and the lower run are connected to one another by a plurality of posts arranged along the longitudinal direction of the crane girder, wherein the posts, are designed in a laminar manner comprising at least one aperture.
15. The crane of claim 2, wherein the struts are connected to the lower run or the upper run using the aperture.
16. The crane of claim 3, wherein the struts are welded to the lower run or the upper run in the region of the aperture.
17. The crane of claim 2, wherein the struts are welded to the lower run or the upper run in the region of the aperture.
18. The crane of claim 4, wherein the lower first strut end is provided with a lower aperture, against which the lower run lies, and the upper second strut end is provided with an upper aperture against which the upper run lies.
19. The crane of claim 3, wherein the lower first strut end is provided with a lower aperture, against which the lower run lies, and the upper second strut end is provided with an upper aperture against which the upper run lies.
20. The crane of claim 2, wherein the lower first strut end is provided with a lower aperture, against which the lower run lies, and the upper second strut end is provided with an upper aperture against which the upper run lies.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A reciprocating well pump assembly, comprising:
a barrel having an axis;
a piston sub assembly reciprocally and slidably carried within the barrel between up stroke and down stroke positions, the piston sub assembly having a bore for receiving well fluid from the well during the down stroke;
a travelling valve element in the piston sub assembly that moves between an open position allowing the well fluid to flow up the bore into the barrel above the piston sub assembly during the down stroke to a closed position during the up stroke for lifting the well fluid located in the barrel above the piston sub assembly;
a standing valve at an upper end of the barrel that is movable between an open position during the up stroke of the piston sub assembly and a closed position during the down stroke of the piston sub assembly;
a relief port extending from the bore of the piston sub assembly into the barrel; and
a relief port valve that closes the relief port during the down stroke and part of the upstroke, and which opens the relief port as the piston sub assembly nears a top of the stroke, to reduce fluid pressure in the barrel above the piston sub assembly and allow the standing valve to move to the closed position at the top of the stroke.
2. The well pump assembly according to claim 1, wherein the relief port extends from the bore to an annulus located between the piston sub assembly and the barrel.
3. The well pump assembly according to claim 1, wherein:
the piston sub assembly has a piston that slidably engages the bore; and
the relief port extends from the bore to an annulus in the barrel surrounding the travelling valve element above the piston.
4. The well pump assembly according to claim 1, further comprising:
a stop located in the barrel below the standing valve; and wherein
the relief port valve engages the stop as the piston sub assembly nears the top of the stroke to cause the relief port to open.
5. The well pump assembly according to claim 1, further comprising:
a stop in the barrel below the standing valve; wherein
the relief port valve moves in unison with the piston sub assembly during the up stroke until reaching the stop; and
continued upward movement of the piston sub assembly relative to the relief port valve after the relief port valve reaches the stop causes the relief port valve to open the relief port.
6. The well pump assembly according to claim 1, further comprising:
a spring that urges the relief port valve toward a closed position.
7. The well pump assembly according to claim 1, wherein the relief valve comprises:
a valve sleeve mounted around a body of the piston sub assembly, the valve sleeve having a closed position blocking the relief port and an open position opening the relief port;
the valve sleeve being in the closed position and movable in unison with the body of the piston sub assembly during the down stroke and during the up stroke until the piston sub assembly nears the top of the stroke, at which point, the body of the piston sub assembly moves upward relative to the valve sleeve, causing the valve sleeve to move to the open position; and
a spring urging the valve sleeve toward the closed position.
8. The well pump assembly according to claim 1, further comprising:
a downward facing relief valve stop shoulder in the barrel below the standing valve; and wherein the relief valve comprises:
a valve sleeve mounted around a body of the piston sub assembly, the valve sleeve having a closed position, blocking the relief port and an open position opening the relief port;
the valve sleeve being in the closed position and movable in unison with the body of the piston sub assembly during the down stroke and during the up stroke until the valve sleeve contacts the valve sleeve stop shoulder, at which point, the body of the piston sub assembly moves upward relative to the valve sleeve past the valve sleeve stop shoulder, causing the valve sleeve to move to the open position;
a spring urging the valve sleeve upward on the body of the piston sub assembly toward the closed position; and
a retainer on the body of the piston sub assembly that limits upward movement of the valve sleeve relative to the body of the piston sub assembly.
9. The well pump assembly according to claim 1, further comprising:
an electric motor that rotates a drive shall;
a linear actuator operatively coupled between the motor and the piston sub assembly for converting rotational motion of the drive shaft, to reciprocating motion of the piston sub assembly.
10. A reciprocating well pump assembly, comprising:
a barrel having an axis;
a piston reciprocally carried within the barrel, between up stroke and down stroke positions;
a travelling valve mounted to the piston for movement in unison, the travelling valve having a tubular body with a bore and a travelling valve element within the bore that is movable relative to the tubular body between a closed position during the up stroke of the travelling valve and an open position during the down stroke of the travelling valve;
a tubular body relief port extending from the bore through a side wall of the tubular body;
a standing valve at an upper end of the barrel that is movable between an open position during the up stroke of the travelling valve and a closed position during the down stroke of the travelling valve, the standing valve being in fluid communication with the bore of the body of the travelling valve for receiving well fluid lifted by the piston during the upstroke;
a valve sleeve mounted around the tubular body, defining a valve sleeve annulus between the barrel and the valve sleeve, the valve sleeve being axially movable relative to the tubular body between a closed position, closing the tubular body relief port, and an open position, communicating well fluid in the valve sleeve annulus with the well fluid in the bore;
a spring urging the valve sleeve toward the closed position;
a stop in the barrel positioned for contact by the valve sleeve a selected distance from a top of the up stroke, enabling the tubular body to continue movement toward the top of the up stroke relative to the valve sleeve and placing the valve sleeve in the open position;
an electric motor located below the barrel; and
a linear actuator between the motor and the piston for stroking the piston in response to rotational motion of the motor.
11. The well pump assembly according to claim 10, wherein the valve sleeve annulus is located above the piston.
12. The well pump assembly according to claim 10, further comprising:
a lip on an upper end of the tubular body; and
wherein the spring urges an upper end of the valve sleeve against the lip.
13. The well pump assembly according to claim 10, wherein the well pump assembly further comprises:
an annular lip on an upper end of the tubular body, the spring urging an upper end of the valve sleeve against the lip; wherein
the stop comprises a downward facing shoulder; and
during the upstroke, the lip moves upward past the downward facing shoulder after the upper end of the valve sleeve contacts the downward facing shoulder.
14. The well pump assembly according to claim 10, wherein the relief port is located below the travelling valve.
15. The well pump assembly according to claim 10, wherein:
the valve sleeve has a valve sleeve relief port that registers with the tubular body relief port while the valve sleeve is in the open position, and which is misaligned with the tubular body relief portion while the valve sleeve is in the closed position.
16. A method of pumping well fluid from a well with a reciprocating well pump assembly having a barrel, a piston sub assembly carried in the barrel and having a bore, a travelling valve element in the piston sub assembly, and a standing valve element in the barrel, the method comprising:
providing a relief port extending from the bore of the piston sub assembly and a relief port valve;
lowering the piston sub assembly in the barrel while the relief port valve and the standing valve element are closed, causing well fluid in the well to enter the bore and opening the travelling valve to admit the well fluid into the barrel above the piston;
moving the piston sub assembly upward in the barrel while the travelling valve and relief port valve are closed, causing the standing valve element to open and the piston sub assembly to lift the well fluid in the barrel upward past the standing valve element; then
prior to reaching a top of the stroke, opening the relief port valve, causing the well fluid in the barrel to flow through the relief port into the bore and allowing the standing valve element to close.
17. The method according to claim 16, wherein opening the relief port valve comprises engaging the relief port valve with a stop provided in the barrel, and continuing to move the piston sub assembly upward relative to the relief valve toward the top of the stroke.
18. The method according to claim 16, further comprising urging the relief port valve to a closed position.
19. The method according to claim 16, wherein:
during the upstroke while the relief port valve is closed, a fluid pressure of the well fluid in the bore below the travelling valve will be less than a fluid pressure of the well fluid in the barrel above the travelling valve; and
opening the relief port valve lowers the fluid pressure of the well fluid in the barrel above the travelling valve.
20. The method according to claim 16, wherein moving the piston sub assembly upward comprises:
operating an electric motor to rotate a drive shall; and
converting rotation of the drive shaft into linear movement of the piston sub assembly.