COMPENSATING DEVICE FOR VOLUMETRIC PUMPS

Abstract

A compensating device for volumetric pumps, comprising: a storage tank (2) predisposed for being connected to the delivery line (O) of a pump (P) and to a source of pressurized gas (A); a control valve (3) arranged for opening or closing the connection between the tank (2) and the source of pressurized gas (A); a control module (4) connected to the control valve (3). The device comprises a level sensor (5) associated with the tank (2) for detecting a threshold level for a liquid within the tank (2) and connected to the control module (4) for transmitting to the module (4) at least one operating signal indicating a liquid level higher than the threshold level. The control module (4) is configured to determine the opening of the control valve (3) in the presence of said operating signal and to determine the closing of the control valve (3) in the absence of said operating signal.

Description

The object of the present invention is a compensating device for volumetric pumps.

The invention finds advantageous use in compensating pulsations in the flow rate and pressure at the delivery point of a piston pump, particularly in the presence of abrasive and/or corrosive liquids, as for example in plants for processing ceramic slips.

High power piston pumps that feed the ceramic slip along a processing line are normally used in such plants. Storage tanks placed in communication with the delivery line of the pump are used to compensate for the pulsations in the flow rate and pressure at the delivery point of the pump. These tanks are filled partly with the pumped liquid and partly with the air compressed to a predetermined pressure. To reduce the pulsations in pressure and flow rate at the delivery point of the pump, the pressure inside the tank must remain substantially constant.

The compensating tanks are substantially managed based on the pressure of the air inside the tank. For this purpose, a pressure gauge is placed in communication with the tank and connected to a control panel that determines the opening and closing of a compressed air supply valve. If the pressure drops below a given threshold value, the control panel commands the opening of the valve so as to inject air into the tank again.

The use of a pressure gauge can involve several drawbacks. In fact, operation of the pressure gauge can be negatively affected by the presence of impurities and sudden fluctuations in temperature, thereby jeopardizing proper control of the pressure inside the tank.

The aim of the present invention is to offer a compensating device for volumetric pumps that makes it possible to improve the characteristics of the devices that are currently available.

Characteristics and advantages of the present invention will become more apparent in the following detailed description of an embodiment of the invention concerned illustrated by way of non-limiting example in FIG. 1 attached hereto, which is a schematic view of the device according to the present invention.

With reference to the figure, the compensating device according to the present invention comprises a storage tank (2) predisposed to be connected to the delivery line (O) of a pump (P) and to a source of pressurized gas (A). The pump (P) is for example a piston pump. The source of pressurized gas (A) is for example a compressed air circuit, normally present in all industrial plant systems. The tank (2) is equipped with a pressure gauge (7) for safety and control functions.

A control valve (3) is interposed between the tank (2) and the source of gas (A). This control valve (3) is arranged for opening or closing the connection between the tank (2) and the source of gas (A), taking on an opening configuration and a closing configuration, respectively. The control valve (3) is connected to a control module (4) that activates the control valve (3) in the opening and closing configurations.

The compensating device comprises a level sensor (5) associated with the tank (2). The level sensor (5) is configured to detect a threshold level for the liquid present inside the tank (2).The level sensor (5) is also connected to the control module (4) for transmitting to the module (4) at least one operating signal indicating a level of liquid higher than the threshold level.

In other words, the level sensor (5) is located at a given height on the tank (2), so as to detect the presence or absence of liquid at that given height, which corresponds to the threshold level. If the sensor (5) detects the presence of liquid, this means that level of liquid inside the tank (2) is equal to or higher than the threshold level and the sensor (5) transmits its operating signal. If the sensor (5) does not detect the presence of liquid, then the level of liquid inside the tank (2) is below the threshold level and the sensor (5) stops transmission of its operating signal and transmits a signal differing from the operating signal.

The sensor (5) is structured so as to directly measure the level of the liquid inside the tank (2). In other words, at least one part or one zone of the sensor (5) is placed in contact with or can enter into contact with the liquid inside the tank (2).This makes it possible to obtain a substantially instantaneous and direct measurement of the level of liquid inside the tank (2).

The sensor (5) is preferably a capacitive type of sensor, but it could be of another type such as a float sensor.

The control module (4) is configured to determine the opening of the control valve (3) in the presence of the operating signal transmitted by the sensor (5) and to determine the closing of the control valve (3) in the absence of said operating signal.

The opening of the control valve (3) enables the introduction of pressurized gas inside the tank (2).The thrust exerted by the gas on the liquid present in the tank (2) produces the lowering of the liquid level. When the level drops below the threshold level, the sensor (5) stops transmitting its operating signal or transmits a signal differing from the operating signal, and the control module determines the closing of the control valve (3). In this manner, by determining the opening and closing of the control valve (3) in relation to the signal transmitted by the level sensor (5), it is possible to keep the liquid level inside the tank substantially constant, and thus also the volume available for the air.

Essentially, the device is controlled based on the volume of air present inside the tank (2), rather than based on the pressure present inside the tank (2) as is the case in currently available devices. This makes it possible to obviate the use of a pressure gauge for controlling the device.

The liquid level inside the tank (2) is detected at predetermined time intervals. Detection frequency is preferably determined so as to prevent excessive rising of the liquid level and simultaneously prevent excessively frequent activation of the control valve (3).

Claims

1. A compensating device for volumetric pumps, comprising: a storage tank (2), predisposed for being connected to the delivery line (O) of a pump (P) and to a source of pressurized gas (A); a control valve (3), arranged for opening or closing the connection between the tank (2) and the source of pressurized gas (A); a control module (4), connected to the control valve (3); characterized in that:it includes a level sensor (5) associated with the tank (2) for detecting a threshold level for a liquid within the tank (2) and connected to the control module (4) for transmitting to said module (4) at least one operating signal indicating a liquid level higher than the threshold level;the control module (4) is configured so as to determine the opening of the control valve (3) in the presence of said operating signal and to determine the closing of the control valve (3) in the absence of said operating signal.

2. The compensating device according to claim 1, wherein the sensor (5) is structured so as to directly measure the level of the liquid inside the tank (2).

3. The compensating device according to claim 1, wherein at least one part or one zone of the sensor (5) is placed in contact with or can enter into direct contact with the liquid inside the tank (2).

4. The compensating device according to claim 1, wherein the level sensor (5) is a capacitive sensor.

5. A control method for a storage tank (2) predisposed for being connected to the delivery line (0) of a pump (P), comprising the following steps: detecting the level of liquid inside the storage tank (2);if the level of liquid is higher than a threshold level, allowing the feeding of pressurized gas to the tank (2);if the liquid level is lower than the threshold level, preventing the feeding of pressurized gas to the tank (2)

6. The method according to claim 5, wherein the liquid level is detected at predetermined time intervals.