A fluid pump has a housing, a chamber having an inlet and an outlet, an inlet valve, an outlet valve, and a plunger. The plunger has a plunger tube extending into the chamber and supported for movement, on a suction stroke, to introduce a fluid into the chamber via the inlet, and, on a discharge stroke, to displace the fluid from the chamber via the outlet. An electromagnetic driving unit moves the plunger in two opposite directions. A magnetic core is located adjacent the plunger for establishing a magnetic path across the electromagnetic driving unit and the plunger. The core is located in the path of movement of the plunger on the suction stroke, and is protected or covered by a material against contact with the fluid in the housing.

A device (102) for an ocular tonometer comprising a dispenser (106) for dispensing and ejecting at least one liquid droplet (302) to the cornea (304) of an eye from a distance to the eye, wherein the dispenser (106) is arranged to eject the at least one droplet (302) such that the droplet (302) causes applanation to the cornea (304). Corresponding eye pressure measuring device, arrangement and method are also disclosed.

A linear compressor includes: a shell including an intake pipe configured to suction a refrigerant, a piston including a piston body, an intake muffler including a first muffler that includes a first muffler body defining a main flow passage and a first muffler flange extending in a radial direction from the first muffler body, and at least one auxiliary flow passage disposed between an outer peripheral surface of the first muffler body and an inner peripheral surface of the piston body and configured to guide the refrigerant remaining between the first muffler body and the piston body to an outside of the piston. A cross-sectional area of the at least one auxiliary flow passage is less than a cross-sectional area of an inlet hole provided at a rear end of the main flow passage and greater than or equal to 10% of the cross-sectional area of the inlet hole.

A linear compressor includes: a frame comprising a body portion, a flange portion extending from a front side of the body portion along a radial direction of the body portion, and a bearing communication hole that is in fluid communication with a front surface of the flange portion and an inner circumferential surface of the body portion, a cylinder coupled to the body portion, a piston that is disposed in the cylinder and that is configured to reciprocate along an axial direction of the cylinder, and a valve member that is disposed at the frame and that is configured to open and close the bearing communication hole based on a pressure of air between the cylinder and the piston.

A piston for a compressor and a compressor including the same are disclosed. The piston is used in a compressor which compresses and discharges refrigerant suctioned into a cylinder. The piston includes a cylindrical slider and a head. The slider has an outer diameter corresponding to an inner diameter of the cylinder and defines a suction space in which the refrigerant suctioned in the cylinder is received. The head is coupled to the slider, in which a compression space is provided in the front and a suction space is provided in the rear, and in which a suction port communicating with the suction space and the compression space is formed, in which the head includes an inner body and an outer body surrounding the inner body, and the suction port is formed between the inner body and the outer body.

An injection assembly configured to supply an additive from a reservoir to a fluid in a pipe has a pipe portion and an injection pump. The injection pump has a linear motor comprising a stator and an armature reciprocatingly driven by the stator, and a pump portion comprising an additive inlet chamber. A piston coupled to the armature is configured to reciprocate in said inlet chamber, thereby alternatingly compressing and decompressing a volume of said inlet chamber, an additive outlet chamber in fluid communication with the pipe portion, and a bypass channel between the inlet and outlet chambers.

Automatic electric actuation of the pump of a liquid dispenser apparatus is provided by a stepper motor having a threaded hollow liquid-conducting tube positioned therein and configured such that motor drives the hollow tube up and down in response to supply of a plurality of electrical pulses thereto. A lower end of the hollow tube is constructed to inter-fit with a stem of the pump such that driving the hollow tube up and down creates a pumping action.

Disclosed in the present invention is an electromagnetic pump, including: a pump body; an inner iron core, including a central cylinder, an axis of the central cylinder basically coinciding with an axis of the electromagnetic pump; a plurality of outer iron cores, disposed at least partially surrounding the inner iron core; a winding, at least partially disposed on the outer iron cores; and a pump channel mechanism, at least partially disposed between the outer iron cores and the inner iron core, where the pump channel mechanism includes: a first pump channel wall, a second pump channel wall, a circulation channel, and a cavity dividing structure, and being used for supporting the first pump channel wall and the second pump channel wall, the cavity dividing structure being further used for dividing the circulation channel, to divide the circulation channel into a plurality of channels.

The present utility model relates to the technical field of water pumps, and more particularly, to a miniature electromagnetic water pump, which includes a pump body, a magnetic core plunger device installed in the pump body, an electromagnetic device sleeved outside the pump body, and a throttle valve device connected with the magnetic core plunger device, the magnetic core plunger device is used to pump the liquid outside the pump body to the throttle valve device, the electromagnetic device generates a pulsed electromagnetic field to push the magnetic core plunger device to reciprocate in the pump body, the miniature electromagnetic water pump of the present utility model has the advantages of stable liquid output and good liquid flow continuity.

An electromagnetic pump (100). The electromagnetic pump (100) comprises a conduit (101) comprising an inlet (103) and an outlet (105). A first magnetic field generating unit (109) is provided for generating a first magnetic field having a first component with a first direction in the conduit. A second magnetic field generating unit (111) is provided for generating a second magnetic field having a second component with a second direction in the conduit (101), the second direction being substantially opposite to the first direction. A piston member (113) is disposed within the conduit, the piston member (113) being moveable within the conduit (101) under the influence of the first and/or second magnetic fields to pump fluid received from the inlet (103) of the conduit (101) to the outlet (105) of the conduit (101).