The present invention relates to a rotational viscometer comprising a measuring head associated with a spindle to be immersed in a fluid sample, and to an equipment for determining the viscosity comprising said viscometer.

Background to the invention Kinematic viscosity is measured by determining the tangential force required to displace particles in material with a specific deformation velocity. The viscosity is obtained as a result of the relationship between tangential force and shear deformation, the measuring unit being the CentiPoise (cP). Rotational viscometers are instruments that function by means of a rotating shaft to which is attached a spindle that is immersed in the fluid sample to be analysed. The viscometer measures the resistance torque produced on rotation by a spring installed inside the measuring head. The resulting resistance or torque is the measurement of the viscosity flow and depends on the spindle's rotation speed and the type of spindle used.

The rotational viscometers that exist on the market include a screen and keyboard integrated in the measuring head, so that the user can enter parameters and view the results. In these instruments, the same measuring head is equipped with various types of spindles able to work at different speeds. However, these viscometers have the inconvenience that the spring inside the head is configured for a single measurement range; low range (20-2,000,000 cP), medium range (100-13,000,000 cP) or high range (200-106,000,000 cP), meaning that the same device cannot measure all viscosity ranges.

Another inconvenience presented by existing rotational viscometers is the need to have an additional measuring accessory for non-flowing fluid samples (for example, cosmetic creams). These fluids require the use of a spindle that moves vertically while measuring in order to avoid cavitation. Description of the invention

The objective of the present invention is to provide a rotational viscometer that overcomes the aforementioned inconveniences and has the advantages described below.

In accordance with this objective, according to a first aspect, the present invention provides a rotational viscometer comprising a measuring head associated with a spindle to be immersed in a fluid sample, characterised in that it includes a control unit comprising: a. a wired or wireless communication module adapted to receive and/or transmit signals from a remote terminal by the user of said viscometer, and

b. a processing module associated with said wired or wireless communication module to provide a control signal to said head based on a signal coming from a graphic interface on the remote terminal, and in that said control unit is integrated in the measuring head in such a way that together with said head it forms a compact measuring unit susceptible of being controlled from said remote terminal. The present invention is a viscometer with a compact measuring unit equipped with a processing module that can be controlled from a graphic interface on a remote terminal. It is thus obtained an instrument that allows readings to be taken with ease, without being in front of the measuring head. In addition, the graphic interface on the remote terminal can be adapted to suit current tablet- or smartphone-based working platforms. This unit also has the advantage that it can be interchangeably coupled from and decoupled from a framework.

In the present invention, the expression referring to said control unit being integrated in the measuring head in such a way that together with said head it forms a compact measuring unit susceptible of being controlled from said remote terminal is intended to mean that the control unit forms part of a compact measuring unit that includes the measuring head, so that said compact measuring unit is susceptible of being controlled from the remote terminal.

Likewise, the expression referring to said measuring head being associated with a spindle is intended to mean that said measuring head is attachable to a spindle.

Preferably, this compact unit comprises a wireless communication module adapted to receive and/or transmit radiofrequency signals from a smart, mobile remote terminal (for example a tablet or smartphone). Advantageously, said wireless communication module is a Bluetooth communication module. In a preferred embodiment, the processing module of the compact viscometer's measuring unit provides a control signal in order to take a measurement based on a signal from the remote terminal indicating: a spindle for a pre-set viscosity range, a rotation speed for the spindle and/ or a sample fluid density value. Preferably, said compact unit is mounted vertically and movably on a framework provided with moving means. Advantageously, said framework includes a control unit comprising: a. a wired or wireless communication unit adapted to receive and/or transmit signals from the remote terminal, and

b. a processing module associated with said wired or wireless communication module to provide a control signal to a drive motor for driving said moving means based on a signal from the remote terminal.

The user can thus control the movement of the head or compact unit from the remote terminal to remotely change the head height or activate the appropriate motor operating mode to measure non-flowing fluid samples (for example, cosmetic creams).

Experts on the subject will be aware that, in order to avoid cavitation in non-flowing fluids of this type, the measurement must be taken with the spindle performing an alternating movement defining an elliptical path that avoids cavitation of the fluid. The present invention allows measurements of this type to be performed without the need for additional accessories.

In a preferred embodiment, the vertical moving means comprise a pair of endless belts vertically arranged on vertical structures on the framework and a pair of securing pieces for securing the head or compact unit, said pieces being integrally attached to each belt in order to vertically move the head or unit between the two vertical structures. Thus the head or compact unit can be very stably and safely moved from the remote terminal. In accordance with a second aspect, the present invention provides an equipment for determining the viscosity of a fluid sample comprising a plurality of compact measuring units, each one of said compact units comprising a measuring head of a pre-set viscosity range (high, medium or low), each of said compact units being susceptible of being controlled from the same remote terminal and interchangeably coupled from and decoupled from the same framework in order to measure a different viscosity range using the same equipment.

Thanks to these features, an instrument is obtained that allows a full range of viscosities to be determined using a single equipment, by quickly and easily changing only one compact measuring unit for another that is immediately recognised by the remote terminal that forms a part of the equipment. This remote terminal may be, for example, a smart mobile remote terminal, tablet or smartphone, equipped with a communication module, preferably wireless, to receive and/or transmit signals to said plurality of compact measuring units, said remote terminal including a graphic user interface. Brief description of the drawings

To assist understanding the above, drawings are provided that schematically, illustratively and non-restrictively represent an embodiment of the invention. Figure 1 is a view of a viscometer comprising a measuring head or compact measuring unit mounted on a framework with vertical moving means.

Figure 2 is an exploded view of the viscometer in figure 1. Figure 3 shows a view of the vertical structures supporting the endless belts and the drive motor for said belts.

Figure 4 shows a cross section of figure 3. Figure 5 shows three compact measuring units forming part of the measuring equipment of the present invention. Each of these compact units measures viscosity within a set range (high, medium, low).

Figure 6 is a perspective view of a viscometer comprising a compact measuring unit mounted on a conventional foot. Description of a preferred embodiment

Below is a description of the viscometer and viscosity measuring device constituting the invention with reference to figures 1 to 6.

The rotational viscometer 1 claimed comprises a measuring head 2 associated with a spindle 3 to be immersed in a fluid sample and a control unit 4 comprising: a. a wireless communication module adapted to receive and/or transmit radiofrequency signals from a remote user terminal 5, and

b. a processing module associated with the wireless communication module to provide a control signal to the measuring head 2 based on a signal sent from a graphic interface on the remote terminal 5. The control unit 4 is integrated in the measuring head 2 in such a way that together with said head 2 it forms a compact unit 6 that can be controlled from said remote terminal 5.

Figure 1 shows a viscometer with a compact measuring unit 6 mounted detachably on a framework 7 that includes moving means to vertically move said compact unit 6. Figure 6 shows the same compact unit 6, but in this case arranged on a conventional foot. In both cases, the compact measuring unit 6 is controlled from a remote terminal 5 that may be, for example, a smart mobile terminal such as a tablet with a Bluetooth module (see representation of the terminal in figure 1 ). As discussed in the description of the invention, it is thus obtained an instrument that allows readings to be taken with ease, without the user being in front of the measuring head.

Signals indicating the selected spindle 3, spindle 3 rotation speed and/or a fluid density value can be sent to the control unit 4 of the compact unit 6 by the remote terminal 5. These signals are necessary in order for the head 2 to perform a simple viscosity measurement. The same remote terminal 5 can send signals indicating maximum and minimum limits for viscosity values that can be associated with an alarm that will sound on the remote terminal 5 itself. Below it is presented an image of the graphic interface on the remote terminal 5, for example a Tablet or Smartphone, showing a progress bar with the maximum and minimum limits for viscosity value. If these limits are exceeded an alarm will sound on the remote terminal 5 and the progress bar will change of colour.

Figure 3 shows an exploded view of the viscometer 1 in figure 1 , including the framework 7, which incorporates moving means to vertically move the measuring head 2 associated with the spindle 3. As can be seen in figure 3, the framework 7 is enclosed within a protective casing 13 and the measuring head 2 is located inside the compact measuring unit 6.

In order to vertically move the measuring head 2, vertical structures 9 supporting endless belts 10 are integrally attached to securing pieces 1 1 for securing the compact unit 6. The belts 10 are actuated and moved by a motor 12 associated with a control unit on the framework 7 that includes a second wireless communication module to receive and/or transmit signals from the remote terminal 5.

The user can thus control the movement of the measuring head 2 from the remote terminal 5 in order to remotely change the head height or to activate the appropriate operating mode to measure non-flowing fluids (for example, cosmetic creams). Figures 3 and 4 show two further views of the vertical structures 9 on which the endless belts 10 and pieces 1 1 for securing the compact measuring unit 6 are mounted.

Figure 5 shows three compact measuring units 6a, 6b and 6c that form part of a single measuring equipment and are controlled from the same remote terminal 5. Each of said units 6a, 6b and 6c comprises a measuring head 2 and spindle 3 with a spring 14 tared for a different viscosity range. For example, a low range (20-2,000,000 cP), medium range (100- 13,000,000 cP) or high range (200-106,000,000 cP). As was discussed in the description of the invention, said units 6a, 6b and 6c can be interchangeably coupled from and decoupled from the same framework 7 in order to measure viscosities in different ranges with the same equipment. Thanks to these features, an instrument is obtained that allows a full range of viscosities to be determined with a single equipment, by quickly and easily changing only one compact measuring unit 6a for another 6b that will immediately be recognised by the remote terminal 5 forming part of the equipment..

Although this refers to a concrete embodiment of the invention, it is evident to an expert on the subject that the viscometer 1 described may vary or be modified in numerous ways, and that all the details mentioned may be replaced by other technically equivalent features without departing from the scope of protection defined in the attached claims.