A pulsation-free wet spraying machine resolves the issue of pulsing during pumping of a concrete spraying machine. The wet spraying machine includes a frame, a pumping mechanism, a swing mechanism and a hydraulic system, wherein the pumping mechanism includes a hopper, a material chamber, a concrete feeding mechanism, an auxiliary feeding mechanism and a distribution valve, the hopper is disposed above the material chamber, the concrete feeding mechanism and the auxiliary feeding mechanism each include a hydraulic cylinder, a concrete piston and a concrete cylinder, the concrete cylinder of the concrete feeding mechanism and an auxiliary concrete cylinder of the auxiliary feeding mechanism are both connected with the material chamber, a discharge port is disposed on the material chamber, sealing between the distribution valve and the discharge port is provided by a sealing ring, the distribution valve is disposed inside the material chamber, a front friction plate and a rear friction plate are further disposed inside the material chamber, the swing mechanism includes a swing hydraulic cylinder, a mandrel, a swing arm and a swing hydraulic cylinder base, and the mandrel drives the distribution valve to swing. In addition, The pulsation-free wet spraying machine stably feeds a material, has a compact structure, and is wear-resistant.

A pulsation-free wet spraying machine resolves the issue of pulsing during pumping of a concrete spraying machine. The wet spraying machine includes a frame, a pumping mechanism, a swing mechanism and a hydraulic system, wherein the pumping mechanism includes a hopper, a material chamber, a concrete feeding mechanism, an auxiliary feeding mechanism and a distribution valve, the hopper is disposed above the material chamber, the concrete feeding mechanism and the auxiliary feeding mechanism each include a hydraulic cylinder, a concrete piston and a concrete cylinder, the concrete cylinder of the concrete feeding mechanism and an auxiliary concrete cylinder of the auxiliary feeding mechanism are both connected with the material chamber, a discharge port is disposed on the material chamber, sealing between the distribution valve and the discharge port is provided by a sealing ring, the distribution valve is disposed inside the material chamber, a front friction plate and a rear friction plate are further disposed inside the material chamber, the swing mechanism includes a swing hydraulic cylinder, a mandrel, a swing arm and a swing hydraulic cylinder base, and the mandrel drives the distribution valve to swing. In addition, The pulsation-free wet spraying machine stably feeds a material, has a compact structure, and is wear-resistant.

A reciprocating compressor includes a cylinder that defines an inner space, a piston that is located in the inner space of the cylinder and that defines a compression space configured to receive refrigerant, a discharge cover that is coupled to a side of the cylinder and that defines a discharge space configured to receive refrigerant discharged from the compression space, and a valve plate that is located at a side space defined at the side of the cylinder and that partitions the side space into the compression space and the discharge space. The valve plate defines a discharge hole through which the compression space and the discharge space communicate with each other, in which the discharge hole includes an inlet that faces the compression space and an outlet that faces the discharge space. The inlet and the outlet have different shapes.

A reciprocating compressor includes a cylinder that defines an inner space, a piston that is located in the inner space of the cylinder and that defines a compression space configured to receive refrigerant, a discharge cover that is coupled to a side of the cylinder and that defines a discharge space configured to receive refrigerant discharged from the compression space, and a valve plate that is located at a side space defined at the side of the cylinder and that partitions the side space into the compression space and the discharge space. The valve plate defines a discharge hole through which the compression space and the discharge space communicate with each other, in which the discharge hole includes an inlet that faces the compression space and an outlet that faces the discharge space. The inlet and the outlet have different shapes.

A pump (2) comprising a stator (4) and a rotor (6) axially and rotatably movable relative to the stator, the stator comprising a rotor shaft receiving cavity (18), an inlet (14) and an outlet (16) fluidly connected to the rotor shaft receiving cavity (18), the rotor comprising a shaft (24) received in the rotor shaft receiving cavity (18). The rotor shaft (24) comprises a cavity (39) receiving a piston portion (12) of the stator therein to form a piston chamber (42), a seal (44) mounted between the piston portion (12) and inner sidewall of the cavity (39) to sealingly close an end of the piston chamber (42). The rotor further comprises a port (38) fluidly connecting the piston chamber (42) to an outer surface (60) of the rotor shaft (24), the port (38) arranged to overlap at least partially the inlet (14) over a rotational angle of the rotor corresponding to a pump intake phase, and arranged to overlap at least partially the outlet (14) over a rotational angle of the rotor corresponding to a pump expel phase.

A liquid pump having a pump liner and a pump piston, wherein the pump liner defines a central longitudinal bore and a transverse inlet bore communicating with the central bore for conveying a liquid. The pump piston has a centerline intersecting with a centerline of the transverse inlet bore, and further has a flat surface formed parallel with the piston centerline at a distal end of the piston. The flat surface defines a cut-out portion of the piston, wherein the cut-out portion has a hydraulic diameter equal to the diameter of the transverse inlet bore of the liner, and a distance from the centerline of the piston to the flat surface defining the cut-out portion is greater than or equal to of the diameter of the transverse inlet bore of the liner.

The dosing apparatus comprises a conveying device (5), which is driven by at least one conveying drive (4), for conveying fluid from the interior (3) of a container (2). The fluid by means of the conveying device (5) is conveyable from the container to a dispensing opening (6). The conveying device (5) comprises a cylinder (7) having at least one intake opening (11) and at least one outlet opening (12) on an inner cylinder wall (8), and a first piston (9) and a second piston (10). The first piston (9) and the second piston (10) are mounted within the cylinder (7) so as to be displaceable in the longitudinal direction. Furthermore, the first piston (9) and the second piston (10) between the end sides thereof and together with a portion of the inner cylinder wall (8) delimit a variable fluid volume (17).

A double acting alpha Stirling refrigerator includes a piston cylinder and a piston, the piston is provided in the piston cylinder. The piston is in a clearance fit with an inner wall of the piston cylinder. A closed cavity is formed inside the piston. A cross-shaped four-way pipe is provided in the cavity of the piston. A one-way air outlet valve and a one-way air inlet valve are further respectively provided on the four-way pipe in the cavity of the piston. An air outlet for connecting the cavity of the piston to the inner cavity of the piston cylinder is provided on the piston. A traction frame movable relative to the piston cylinder is provided outside the piston cylinder, and the movement of the piston is controlled by the movement of the traction frame.

A double acting alpha Stirling refrigerator includes a piston cylinder and a piston, the piston is provided in the piston cylinder. The piston is in a clearance fit with an inner wall of the piston cylinder. A closed cavity is formed inside the piston. A cross-shaped four-way pipe is provided in the cavity of the piston. A one-way air outlet valve and a one-way air inlet valve are further respectively provided on the four-way pipe in the cavity of the piston. An air outlet for connecting the cavity of the piston to the inner cavity of the piston cylinder is provided on the piston. A traction frame movable relative to the piston cylinder is provided outside the piston cylinder, and the movement of the piston is controlled by the movement of the traction frame.

A metering pump is joined to the stepping motor, includes an eccentric mechanism converting a revolving motion of the stepping motor into a reciprocating motion of a plunger, and makes a constant liquid delivery by sucking and discharging an anesthetic agent through variations in the cubic volume of a cylinder caused by the reciprocating motion of the plunger. The control section: calculates a suction and discharge cycle T of the metering pump on the basis of a set anesthetic-gas concentration and a fresh-gas flow rate; sets a discharge period T2 of the cycle T to be longer than a suction period T1 of the cycle T; and controls the revolution speed of the stepping motor so that the travelling speed of the plunger is kept constant during the discharge period T2.