RU2653719C1 - Piston high-pressure pump - Google Patents

Abstract

FIELD: motors and pumps.

SUBSTANCE: invention relates to pneumatic systems, in particular, to devices for generating high pressure of air or gas in a main pipe, and can be used for metrological purposes for supply of means of controlling and measuring pressure in high pressure mode. Pump includes housing 1, working chamber 2 formed by piston 3 of smaller diameter and cylinder 4, and a working chamber 5 formed by larger diameter piston 6 and cylinder 7 separated by valve assembly 8 with inlet valve 9 and outlet valve 10 associated with a gas supply system and a gas pressure consumption system. Pistons 3 and 6 are located at opposite ends of rod 11, longitudinal axial hole 12 is formed in valve assembly 8 for moving the rod. In neck of axial hole 12 there is sealing elastic ring 13. At end of rod 11 on side of piston 3 of smaller diameter there is bypass channel 14. Valve assembly 8 comprises additional overflow valve 15. In bypass channel 14 located in rod 11 there is adjusting device 16 comprising internal thread groove 17 in communication with bypass channel 14, in which screw 18 is located.

EFFECT: improved performance of the pump and increased reliability of its operation are provided.

5 cl, 6 dwg

Description

The invention relates to structural elements of pneumatic systems, and in particular to devices that create high air or gas pressure in the line, and can be used for metrological purposes to power control and pressure measurement devices in high pressure mode with the necessary and sufficient air or gas performance during their calibration or verification.

Designs of piston devices that create high pressure incorporate elements such as cylinders, pistons, suction and discharge valves, which form the so-called “dead” or “harmful” space when the piston is at top dead center, composed of over-valve and sub-valve spaces, communication channels, as well as the gap between the bottom of the piston and the cylinder cover, necessary to compensate for the thermal expansion of the piston, which affects the performance of the devices. "Harmful" space affects the filling of the cylinder with atmospheric air, because first, expansion of compressed air that is not pushed out of the harmful space by the piston occurs, reducing the performance of the piston device. Also, when the piston moves to the top dead center of the device, if the piston is driven by the drive, the pressure of the harmful space acting on the piston is explosive, expanding in the cylinder, having a destructive effect on the kinematics of the piston drive: connecting rod, crank, transmission links, etc. if the speed of the piston does not exceed the speed of expansion of the air.

Known devices are sources of pneumatic pressure and vacuum, such as pneumatic pumps Wika CPP30, Druck LPP30, Crystal PN: 2907 and Crystal PN: 2908, Germany, Druck PV211, Merian M-600KT, Heise TP1-40 and Fluke 700PTP-1, USA, Elemer PV-60, Moscow, Russia and H-2,5, Chelyabinsk, Russia, as well as a device for creating pneumatic pressure, patent RU 2488788 C1, designed to create excess pressure or vacuum during calibration of pressure measuring instruments by direct comparison of readings reference and verifiable pressure measuring instruments.

These pneumatic pumps have the same set of basic elements that provide pressure: a cylinder with inlet and outlet valves, a piston, a lever piston drive with a compression return spring to provide piston movement and create pressure or vacuum in the system of standard and calibrated pressure measuring instruments during calibration or verification. When compressing the air in the pump, the piston at the end of the stroke is adjacent to the cylinder cover, thereby reducing the harmful space, and the air pressure remaining after the compression process helps the return spring to move the piston to its original position. As a rule, the sealing of the piston in the pump cylinders is ensured by rubber seals, for which the movement speed is allowed up to 0.5 m / s, and the compression frequency of the lever arm of the pump by the operator manually does not allow reaching such a piston speed. At low cost, the disadvantage of hand pumps is that the compression of the lever handles is carried out manually by the operator.

Compressors are also widely used in the national economy for compressing and supplying air or any gas under pressure. Compressors incorporate an electric motor for driving piston assemblies through a transmission element - a belt drive, which provides a high linear speed of movement of the pistons. In this case, the tightness of the piston in the cylinder is ensured by metal sealing rings, the speed of movement of which can be permissible up to 7 m / s. Therefore, the influence of harmful space extends only to the performance of the compressor. In order to eliminate the influence of harmful space in the cylinder walls, grooves are made to transfer compressed gas in the harmful space to the other side of the piston or gas bypass in compressors with spool distribution through special channels in the spool kinematically connected to the piston drive. The representative of the solution with grooves on the cylinder mirror is a piston vacuum pump, presented in A.S. USSR No. 1548510 according to class F04B 37/16, c. 09/18/1987, op. 03/07/1990

The disadvantages of using compressors to power calibrated or verifiable means of monitoring or measuring pressure, containing a small amount of closed working cavities or pressure receivers, are that the compressors are large in size, excess capacity, and correspondingly high cost. In addition, in the process, they create a high level of noise.

Closest to the technical nature of the claimed is a high-pressure piston pump with electric drive, presented in the patent for invention No. 2594540 by class. F04B 7/02, 37/16, 9/02, s. September 29, 2015, op. 08/20/2016

The known piston pump comprises a housing in which two cylindrical working chambers are arranged on one longitudinal axis and arranged to move from the electric drive along their longitudinal axis, a piston mounted on one end of the rod, while the chambers are equipped with exhaust and inlet valves and have the ability communication between each other by means of bypass elements, as well as working chambers made of different diameters and separated by a valve assembly in which the inlet and outlet are located th valve, grooves are made, communicating valves with chambers, in the center of the assembly there is a longitudinal axial hole for the passage of the rod, in which, on the side of the chamber of smaller diameter, a narrowing is made with an elastic sealing ring placed in it, a bypass channel is made at the other end of the rod, and a second piston is fixed , while each of the pistons is commensurate with its chamber and has the ability to move only in it, the exhaust valve is in communication with a smaller diameter chamber, and the inlet valve with a larger diameter chamber.

This design solves the problem of eliminating the influence of harmful space by performing a bypass channel, thus increasing the pump performance and relieving pump kinematics from the effect of explosive expansion of gas pressure in the harmful space when the piston passes through the smaller diameter of the end position when it is compressed.

The disadvantage of this device is that the bypass channel made at the end of the rod does not have a specific dimension. And this affects the rate of bypass of air or gas and the degree of decrease in its pressure. With a large channel size, the outflow of air or gas from the harmful space of a smaller diameter chamber, at the end of the piston stroke, into the larger diameter chamber will occur quickly, spasmodically. The pressure in the small-diameter chamber will also decrease rapidly, which will predetermine a pneumatic shock in the larger-diameter chamber. This will have a devastating effect on the kinematic diagram of the pump. With a small channel size, the outflow of air or gas from the harmful space of a smaller diameter chamber, at the end of the piston stroke, into the larger diameter chamber will occur slowly. There will be an effect of throttling the flow of air or gas. Perhaps in this case, when the piston is small in diameter at the end of the stroke, not all the volume of air or gas under pressure from the harmful space of the smaller diameter chamber will flow into the larger diameter chamber. And then there will be an explosive expansion of the gas volume from the remaining pressure in the harmful space of the chamber of a smaller diameter when the piston passes the extreme position. Also, the speed of movement of the piston of a small-diameter chamber will affect the rate of outflow of gas or air through the bypass channel. It is not possible to perform an accurate calculation of the size of the bypass channel for all pump operating conditions, design features, and the amount of harmful space in a chamber of smaller diameter to ensure reliable and continuous operation of the pump.

The objective of the proposed technical solution is to improve the operational characteristics of the pump while increasing the reliability of its operation.

The problem is solved in that in a high-pressure piston pump containing a housing in which two cylindrical working chambers are located on one longitudinal axis and arranged to move from the drive along the longitudinal axis of the piston mounted on one end of the rod, while the working chambers are separated by a valve assembly, equipped with exhaust and inlet valves located in it and have the ability to communicate with each other by means of bypass elements, in the center of the assembly there is a a native axial hole for the passage of the rod, in which from the side of the driven end of the rod a narrowing is made with an elastic sealing ring placed in it, a bypass channel is made at the same end of the rod and a second piston is fixed, each piston being commensurate with its chamber and has the ability to move only in it, the exhaust valve is in communication with one chamber, and the inlet valve with the second chamber, according to the invention, the bypass channel in the rod is equipped with an adjustment device, which is made a groove in the rod communicating with the bypass channel with an internal thread, in which a screw is placed with the possibility of movement in it.

In this case, an additional groove in the rod can be located relative to the bypass channel in the rod perpendicular to this channel or on the same axis with it. In this case, the working chambers can be made of different or the same diameter, and the pistons are proportionate to them.

The bypass channel with the adjusting device in the form of a groove communicating with this channel with an internal thread in which the screw is located allows you to adjust the opening of the bypass channel in the groove to optimize any pump operating conditions, design features and the amount of harmful chamber space.

The technical result is an improvement in the operational characteristics of the structure while increasing the reliability of its work.

The inventive high-pressure piston pump with electric drive has a novelty in comparison with the prototype, differing from it by such an essential feature as the presence in the bypass channel at the end of the rod of the adjustment device, which is a groove with an internal thread connected to the bypass channel, in which is located a screw with the ability to move in it, ensuring the achievement of a given result.

The applicant is not aware of technical solutions containing the above distinguishing features that ensure the achievement of a given result, therefore, he believes that the claimed technical solution meets the criterion of "inventive step".

The inventive piston high-pressure pump can be widely used in industry when used for metrological purposes to power control and pressure measuring instruments with high-pressure gas or air with the necessary and sufficient reliability during calibration or verification, therefore, it meets the criterion of "industrial applicability".

The invention is illustrated by drawings, which are presented in:

- FIG. 1 is a sectional view of a high pressure piston pump with different sized chambers and pistons in them;

- FIG. 2 is a general sectional view of a high-pressure piston pump with working chambers and pistons of the same size;

- FIG. 3 is a general sectional view of a piston high-pressure pump in working condition with different-sized working chambers;

- FIG. 4 is a general sectional view of a high pressure piston pump in working condition with working chambers of the same size;

- FIG. 5 is a general view of the adjusting device with the location of the groove perpendicular to the axis of the bypass channel;

- FIG. 6 is a general view of the adjusting device with the location of the groove on the same axis as the axis of the bypass channel.

Structurally, the piston high pressure pump (Fig. 1) comprises a housing 1, a working chamber 2 formed by a smaller diameter piston 3 and a cylinder 4, and a working chamber 5 formed by a larger diameter piston 6 and a cylinder 7, separated by a valve assembly 8 with an inlet valve 9 and an exhaust valve 10, respectively associated with a gas supply system and a gas pressure consumption system (not shown in the drawings). The chambers 2 'and 5' in the housing 1 'can be made of the same diameter and have the same size pistons 3' and 6 'commensurate with them (Fig. 2). In this case, the pistons 3 (3 ′) and 6 (6 ′) are placed at opposite ends of the rod 11 (11 ′), for the movement of which a longitudinal axial hole 12 (12 ′) is made in the valve assembly 8 (8 ′). In the narrowing of the axial bore 12 (12 '), an elastic sealing ring 13 (13') is placed, which seals the chamber 2 (2 ') and the chamber 5 (5') relative to each other. At the end of the rod 11 (11 ') from the side of the piston 3 of smaller diameter (or 3' of the same diameter) there is a bypass channel 14 (14 ') (Fig. 1). Also, the valve assembly 8 (8 ') comprises an additional bypass valve 15 (15'). A smaller piston 3 or a piston 3 ′ is kinematically connected to an electric actuator or a pneumatic or hydraulic actuator (not shown in the drawings). In the bypass channel 14 (14 ') located in the stem 11 (11'), there is an adjustment device 16 (16 '), including a groove 17 (17') communicating with the bypass channel 14 (14 ') with an internal thread, in which is the screw 18 (18 '), screwed into it more or less if necessary. In this case, the groove 17 (17 ') can be located relative to the bypass channel 14 (14') in the rod 11 (11 ') perpendicular to this channel (Fig. 5) or on the same axis with it (Fig. 6).

The piston high pressure pump when supplied to the gas pressure consumption system operates as follows (Fig. 3, 4).

When the pump is operating (Figs. 3, 4), the piston 3 (3 ') kinematically connected to the drive and the piston 6 (6') connected by the rod 11 (11 ') to the piston 3 (3') reciprocate in cylinders 4 (4 ') and 7 (7'). The inlet valve 9 (9 ') allows gas to be sucked into the working chamber 5 (5'), and the exhaust valve 10 (10 ') lets gas under pressure from the working chamber 2 (2'). The bypass valve 15 (15 ') allows the gas to pass from the chamber 5 (5') to the chamber 2 (2 ') in a one-way direction. The longitudinal axial hole 12 (12 ') during operation, communicating between chambers 2 (2') and 5 (5 '), is used to discharge the gas remaining in the harmful space of the working chamber 2 (2') under pressure into the working chamber 5 ( 5').

The operation of the piston pump in the direction of increasing the volume of the working chamber 5 (5 ') ensures that gas is sucked into the chamber 5 (5') by the piston 6 (67) in the cylinder 7 (7 ') through the inlet valve 9 (9'). At this time, the piston 3 (3 ') in the cylinder 4 (4') extrudes gas under pressure through the exhaust valve 10 (10 ') from the power chamber 2 (2') into the gas consumption system. In this case, valves 9 (9 ') and 10 (10') are open, and valve 15 (15 ') is closed under the influence of gas pressure in the working chamber 2 (2').

When the pistons 3 (3 ') and 6 (6') approach their final position (Figs. 3, 4), the exhaust valve 10 (10 ') and the intake valve 9 (9') are closed. In the working chamber 2 (2 ') there is a gas pressure that remains in the harmful space of the communication channels and channels, and in the working chamber 5 (5') - the pressure of the gas supplied through the suction valve 9 (9 ') from the gas supply system. At the same time, the bypass channel 14 (14 ') passes through the sealing ring 11 (11') and connects the working chamber 2 (2 ') with the working chamber 5 (5') through an axial longitudinal hole 12 (12 '). The gas pressure from the harmful space of the working chamber 2 (2 ') passes into the working chamber 5 (5') and the pressure in both chambers is balanced, but the pressure in the working chamber 5 (5 ') becomes higher than the gas pressure present here due to the addition of gas pressure from harmful space of the working chamber 2 (2 '). Bypass valve 15 (15 ') remains closed. In this case, the transition of gas or air from the chamber 2 (2 ') to the chamber 5 (5') occurs very quickly and the pressure in the chamber 5 (5 ') rises stepwise, shock impact on the piston 6 (6'). This depends on the speed of movement of the pistons 3 (3 ') and 6 (6'), the volumes of the chambers 2 (2 ') and 5 (5'), as well as the size of the bypass channel 14 (14 '). The adjusting device 16 (16 ') (Fig. 5, 6) is adjusted using a screw 18 (18') in the groove 17 (17 ') so that the kinematic transition of the top dead center of the piston 3 (3') occurs smoothly, without the impact of the pressure of the harmful space of an explosive nature on the piston 6 (6 '). Air or gas from the harmful space of the chamber 2 (2 ') under pressure flows into the chamber 5 (5') with speed and in full, without having a destructive effect on the details of the kinematics of the piston drive: connecting rod, crank, transmission links, drive.

Thus, the drive, driving the pistons 3 (3 ') and 6 (6') in the reciprocating motion in the cylinders 4 (4 ') and 7 (7'), provides a high-pressure outlet through the exhaust valve 9 (9 ') in gas pressure consumption system by the piston 3 (3 ') in the working chamber 2 (2'), releasing pressure from the harmful space of the working chamber 2 (2 ') at the end of the piston 3 (3') stroke through an adjustable cross-section of the bypass channel 14 (14 ') ) by adjusting device 16 (16 '), thereby unloading the piston 6 (6') from the influence of pressure transmitted from the harmful space of chamber 2 (2 ') to chamber 5 (5') when ode piston 3 (3 ') of the upper dead point.

In comparison with the prototype of the inventive piston pump has better performance and is more reliable in operation.

Claims (5)

1. A piston high-pressure pump, comprising a housing in which two cylindrical working chambers are separated on one longitudinal axis and are arranged to move a piston mounted on one end of the stem from the drive along their longitudinal axis, while the working chambers are divided valve unit, equipped with exhaust and inlet valves located in it and have the ability to communicate with each other through the bypass elements, in the center of the node there is a longitudinal axial hole for passage a rod, in which, on the side of the driven end of the rod, a narrowing is made with a sealing elastic ring placed in it, a bypass channel is made at the same end of the rod and a second piston is fixed, each piston being commensurate with its own chamber and can only be moved in its own chamber , the exhaust valve is in communication with one chamber, and the inlet valve - with a second chamber, characterized in that the bypass channel in the rod is equipped with an adjustment device, which is made in the rod communicating with the the starting channel is a groove with an internal thread, in which a screw is placed with the possibility of movement in it. 2. The piston pump according to claim 1, characterized in that the working chambers are made of different diameters, each of the pistons being commensurate with its own chamber and able to move only in it, the exhaust valve is in communication with a smaller diameter chamber, and the inlet valve with the chamber larger diameter. 3. The piston pump according to claim 1, characterized in that the working chambers are made of the same diameter and the pistons are commensurate with them. 4. The piston pump according to claim 1, characterized in that the additional groove in the rod is located in the rod perpendicular to the axis of the bypass channel. 5. The piston pump according to claim 1, characterized in that the additional groove in the rod is located in the rod on the same axis with the bypass channel.

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