Double-hole ceramic precision injection pump

Abstract

The utility model discloses a double-hole ceramic precision injection pump which comprises a sleeve, a main body seat, a driving motor with a screw rod, a piston rod assembly, an optocoupler limiting assembly and a grating ruler assembly, the upper end of the sleeve is provided with a liquid inlet and a liquid outlet, and the lower end of the sleeve is provided with a piston hole; the piston rod assembly comprises a lead screw nut fixing base, a lead screw nut, a threaded pin, a cylindrical pin and a piston rod. One end of the piston rod is inserted into the sleeve to form a movable cavity with the sleeve, and the other end of the piston rod is connected with a driving motor with a lead screw through a lead screw nut; the grating ruler assembly comprises a grating ruler, a grating ruler fixing plate and a grating ruler reading head; the grating ruler is fixedly installed on the grating ruler fixing plate, and the grating ruler reading head is installed on the lead screw nut fixing seat. The grating ruler fixing plate is mounted on the main body seat; the optocoupler limiting assembly comprises an upper optocoupler limiting switch, a lower optocoupler limiting switch and an optocoupler cover plate.

Description

Technical Field

[0001] This patent relates to the technical field of precision liquid extraction and liquid inlet, and specifically relates to a double-hole ceramic precision injection pump. Technical Background

[0002] As a relatively precise way of liquid extraction and liquid inlet, injection pumps have been widely used in industries such as chemical engineering, medicine, instruments, and petroleum.

[0003] The sealing technology of fluid components includes rigid sealing and elastic sealing. Rigid sealing mainly relies on the tiny gaps on the contact surface to achieve sealing, while elastic sealing relies on the elastic filling effect of the sealing ring to achieve sealing. Compared with the two, rigid sealing does not require a sealing ring, has a simple structure, small friction on the contact surface, and is not prone to scratches. Most importantly, if the rigid sealing technology is used as the sealing method for the moving surface of the injection pump, only the material of the pump head needs to be considered, without considering the applicability of the external sealing ring to the fluid medium and temperature, etc. The precision of elastic sealing is not as good as that of rigid sealing, and it has the problems of easy aging and easy wear. The service life of an injection pump with elastic sealing is much lower than that of a ceramic injection pump.

[0004] Existing precision injection pumps generally use glass + plastic or metal as the pump sleeve and pump head, or use other materials in combination with ceramics to make the pump head. However, due to the limited wear resistance and temperature resistance of glass and plastic, and for the pump head made of composite materials, due to the different thermal expansion coefficients of the materials, it is easy to leak liquid and has a short lifespan when used under temperature changes. At the same time, the pump head of existing injection pumps is generally single-hole. However, it is easy for gas to remain in the single-hole injection pump cavity and not be easily exhausted. The gas entering the injection pump cavity is compressed when the injection pump draws and pushes the liquid, resulting in inaccurate liquid volume being pushed out.

[0005] In addition, currently, the amount of liquid sucked and discharged by most injection pumps is determined by the number of steps of the stepper motor. Often, under certain working conditions, there will be problems of inaccurate quantification caused by the stepper motor losing steps. However, a grating type sensor is a sensor that measures displacement using the principle of grating moiré fringes. A grating is a long strip of optical glass or stainless steel with densely spaced parallel engraved lines, and the engraved line density is 10 - 100 lines / mm. The moiré fringes formed by the grating have an optical magnification effect and an error averaging effect, which can improve the measurement accuracy.

[0006] For this reason, this patent designs a double-hole ceramic precision injection pump, that is, a pump head with two holes, one hole is the liquid inlet, and the other hole is the liquid outlet. When air is mixed into the movable cavity of the injection pump, the designed liquid inlet, liquid outlet on the pump sleeve of the injection pump and the corresponding one-way valve can be used in combination to exhaust the mixed air, that is: after the injection pump extracts a certain amount of liquid from the liquid inlet, then discharge the extracted liquid from the liquid outlet. Before discharging the liquid, the air mixed in the movable cavity will be discharged from the movable cavity prior to the liquid. When feeding liquid next time, the liquid still enters from the liquid inlet, which can avoid the disadvantage that a single-port injection pump may suck back the air staying in the liquid extraction pipe into the movable cavity again during the next liquid feeding due to only one liquid inlet and outlet, thus affecting the accuracy of the injection pump. Summary of the Invention

[0007] To achieve the above object, the present utility model provides a double-hole ceramic precision injection pump, and its specific technical solution is as follows:

[0008] A double-hole ceramic precision injection pump includes a sleeve, a main body seat, a driving motor with a lead screw, a piston rod assembly, an opto-coupler limit component, and a grating scale component. The upper end of the sleeve is provided with a liquid inlet and a liquid outlet, and the lower end is provided with a piston hole; the piston rod assembly includes a lead screw nut fixing seat, a lead screw nut, a threaded pin, and a cylindrical pin; one end of the piston rod is inserted into the sleeve to form a movable cavity with the sleeve, and the other end is connected to the driving motor with a lead screw through the lead screw nut; the grating scale component includes a grating scale, a grating scale fixing plate, and a grating scale reader head; the grating scale is fixedly installed on the grating scale fixing plate, and the grating scale reader head is installed on the lead screw nut fixing seat; the grating scale fixing plate is further installed on the main body seat; the opto-coupler limit component includes two opto-coupler limit switches, an upper one and a lower one, and an opto-coupler cover plate. During operation, the driving motor drives the lead screw nut to rotate, and the cylindrical pin rigidly fixed to the lead screw nut fixing seat guides it to move in a straight line up and down, that is, the piston rod (7) assembly also moves reciprocally up and down to realize the extraction and discharge of liquid.

[0009] Further, both the injection pump sleeve and the piston rod are processed from ceramic materials with wear resistance, corrosion resistance, and high temperature resistance.

[0010] Further, the sleeve is provided with two ports, namely a liquid inlet and a liquid outlet respectively.

[0011] Further, the liquid inlet and the liquid outlet are provided with internal threads and can be directly connected to the matching pipe joints.

[0012] Further, the liquid inlet and the liquid outlet should also be used in combination with one-way valves.

[0013] The present utility model has the following advantages compared with the prior art:

[0014] A double-hole ceramic precision syringe pump provided by the utility model is characterized in that its sleeve and piston rod are both processed from ceramic materials with wear resistance, corrosion resistance and high temperature resistance. A rigid sealing technology is adopted for the contact surface between the sleeve and the piston rod, and a high-precision grinding treatment technology enables the contact surface to have a self-lubricating effect, reducing the frictional resistance of the contact surface. At the same time, the liquid inlet and outlet designed on the syringe pump sleeve are used in cooperation with the corresponding one-way valve or multi-way valve, which can exhaust the air mixed in the inner cavity of the syringe pump, improve the precision and accuracy of the syringe pump, and extend the service life of the syringe pump. At the same time, the grating sensor is a sensor that measures displacement based on the principle of grating moiré fringes. The use of this sensor in the utility model can further improve the measurement accuracy of the syringe pump. Brief Description of the Drawings

[0015] Figure 1 Fig. is a schematic three-dimensional structure diagram of a double-hole ceramic precision syringe pump of the utility model.

[0016] Figure 2 Fig. is a schematic front view sectional structure diagram of a double-hole ceramic precision syringe pump of the utility model.

[0017] Figure 3 Fig. is a schematic side view sectional structure diagram of a double-hole ceramic precision syringe pump of the utility model.

[0018] Figure 4 Fig. is an application embodiment diagram of a double-hole ceramic precision syringe pump of the utility model.

[0019] In the figure, 1 - sleeve; 2 - liquid inlet; 3 - main body seat; 4 - liquid outlet; 5 - optocoupler cover plate; 6 - optocoupler wire outlet; 7 - piston rod; 8 - cylindrical pin; 9 - threaded pin; 10 - upper limit optocoupler; 11 - lower limit optocoupler; 12 - motor lead screw; 13 - dust-proof sealing ring; 14 - lead screw nut fixing seat; 15 - retaining ring; 16 - grating scale read head; 17 - lead screw nut; 18 - grating scale; 19 - grating scale fixing seat; 20 - drive motor with lead screw; 21 - one-way valve at the liquid inlet; 22 - one-way valve at the liquid outlet Detailed Embodiment

[0020] The following further describes a double-hole ceramic precision syringe pump of the utility model in conjunction with the drawings and specific embodiments.

[0021] As Figures 1-3As shown in the figure, a double-hole ceramic precision injection pump includes a sleeve (1), a main body seat (3), a driving motor (4) with a lead screw, a piston rod assembly, an opto-coupler limit component, and a grating scale component. The upper end of the sleeve (1) is provided with a liquid inlet (2) and a liquid outlet (4), and the lower end is provided with a piston hole. The piston rod assembly includes a lead screw nut fixing seat (14), a lead screw nut (17), a threaded pin (9), and a cylindrical pin (8). One end of the piston rod is inserted into the sleeve (1) to form a movable cavity with the sleeve, and the other end is connected to the driving motor (20) with a lead screw through the lead screw nut (17). The grating scale component includes a grating scale (18), a grating scale fixing plate (19), and a grating scale reading head (16). The grating scale (18) is fixedly installed on the grating scale fixing plate (19), and the grating scale reading head (16) is installed on the lead screw nut fixing seat (14). The grating scale fixing plate (19) is further installed on the main body seat (3). The opto-coupler limit component includes two upper and lower opto-coupler limit switches (10, 11) and an opto-coupler cover plate (5). During operation, the driving motor (20) drives the lead screw nut (17) to rotate, and the cylindrical pin (8) rigidly fixed to the lead screw nut (17) fixing seat guides it to move linearly up and down, that is, the piston rod (7) assembly also moves reciprocally up and down to achieve the extraction and discharge of liquid.

[0022] When the injection pump draws liquid, as Figure 4 shown, the liquid outlet one-way valve (22) is closed, the liquid inlet one-way valve (21) is opened, the driving motor (20) with a lead screw drives the piston rod (7) to move downward, and the grating scale component of the grating scale (18) installed on the main body seat (3) and the grating scale reading head (16) installed on the lead screw nut (17) accurately detects the amount of liquid extracted, so that the injection pump can extract liquid more accurately. When the injection pump pushes liquid, the liquid outlet one-way valve (22) is opened, the liquid inlet one-way valve (21) is closed. When the injection pump pushes liquid outward, the principle is the same as when extracting liquid, and a set amount of liquid can be quantitatively pushed out.

[0023] To provide multiple protections for the injection pump, two upper and lower opto-coupler limit switches (10, 11) are installed on the main body seat (3). When the injection pump detects the signal of the upper limit opto-coupler (10), the driving motor (20) with a lead screw of the injection pump drives the piston rod (7) to stop moving upward. When the injection pump detects the signal of the lower limit opto-coupler (11), the driving motor (20) with a lead screw of the injection pump drives the piston rod (7) to stop moving downward.

[0024] Since the pump head of the present utility model is processed from ceramic materials with wear resistance, corrosion resistance, and high temperature resistance, the produced ceramic injection pump is not easily stuck under the conditions of sudden cooling and heating, can be durable and stable, and has an extremely long service life. Coupled with the rigid sealing technology of the contact surface and the high-precision grinding treatment, the airtightness of the pump is further improved, making the pump have higher precision.

Claims

1. A double-hole ceramic precision injection pump, characterized in that: It includes a sleeve, a main body seat, a driving motor with a lead screw, a piston rod assembly, an optical coupling limit assembly, and a grating scale assembly. The upper end of the sleeve is provided with a liquid inlet and a liquid outlet, and the lower end is provided with a piston hole; the piston rod assembly includes a lead screw nut fixing seat, a lead screw nut, a threaded pin, a cylindrical pin, and a piston rod; one end of the piston rod is inserted into the sleeve to form a movable cavity with the sleeve, and the other end is connected to the driving motor with a lead screw through the lead screw nut; the grating scale assembly includes a grating scale, a grating scale fixing plate, and a grating scale reader; the grating scale is fixedly mounted on the grating scale fixing plate, and the grating scale reader is mounted on the lead screw nut fixing seat; the grating scale fixing plate is then mounted on the main body seat; the optical coupling limit assembly includes upper and lower optical coupling limit switches and an optical coupling cover plate.

2. A double-hole ceramic precision injection pump according to claim 1, characterized in that: The injection pump sleeve and piston rod are both made of wear-resistant, corrosion-resistant and high-temperature-resistant ceramic materials.

3. A double-hole ceramic precision injection pump according to claim 1, characterized in that: The sleeve is provided with two openings, namely a liquid inlet and a liquid outlet.

4. A double-hole ceramic precision injection pump according to claim 3, characterized in that: The liquid inlet and the liquid outlet are provided with internal threads, which can be directly connected with the matching pipe joints.

5. A double-hole ceramic precision injection pump according to claim 3, characterized in that: The liquid inlet and the liquid outlet should also be used together with a single-way valve or a multi-way valve.

Images