Dispenser for pasty detergents, particularly in the form of gel with microspheres

Abstract: A dispenser for pasty detergents includes a socket (A) for introducing a detergent container and a chamber (G) in communication with the socket (A) through a one-way detergent inlet valve and with the outside through a one-way outlet valve, a pressure and a vacuum being alternately created in said chamber (G) through a pump (P) provided with a return spring (S). Each of said one-way inlet and outlet valves consists of a membrane (M; V) made of an elastically deformable material and provided with a central bore, and of a corresponding conical shutter (N; Z) suitable to close said bore. The central portion of the membrane is thicker so as to have a greater rigidity, whereby in the closing return motion when it abuts against the conical surface of the shutter (N; Z) it cuts the residual film of detergent possibly remaining and achieves a perfect tightness without risk of dripping.

Description: The present invention relates to apparatuses for dispensing pre-established amounts of pasty detergents, and in particular in the form of gel containing solid abrasive particles such as microspheres. It is known that in addition to conventional liquid detergents there are also special products commonly known as "washing pastes", which are used to wash the hands of users working in contact with substances which are particularly difficult to remove such as grease, oil, dyes, etc. These pastes, often available in the form of gel, usually include very aggressive detergent substances and also microscopic abrasive particles to combine the chemical action and the mechanical action so as to achieve a thorough cleaning. Due to these chemical-physical properties, said detergents can not be dispensed by conventional liquid soap dispensers but require specific dispensers. Such dispensers generally consist of a dispensing group provided with an upper socket wherein the container of pasty detergent is placed upside down, and of one or two valves to control the delivery of the detergent. Examples of dispensers comprising a single valve are disclosed in US-3.838.985 and in GB-1.261.815, wherein a valve closes through elastic means the delivery nozzle of a body in communication with the detergent container. This valve is opened by elastically deforming said body so as to block the access of the detergent from the container and to generate a pressure sufficient to overcome the elastic biasing of the valve. However such a single-valve dispenser does not provide an adequate tightness guarantee, in that it is sufficient that the valve is a little worn by use and/or is deteriorated due to the chemically aggressive nature of the product and the detergent may drip out of the dispenser. Moreover, if the dispenser is used for detergents different in density and/or viscosity the elastic biasing of the valve calibrated on an average value may result too weak for more fluid detergents and too strong for more pasty detergents. A type of dispenser with a better tightness is that including a chamber provided with a valve for the inlet of the detergent from the container and an outlet valve to the delivery nozzle. These valves usually are two one-way ball valves arranged so that, by alternately creating in the chamber a pressure and a vacuum through a small pump, the detergent is first sucked into the chamber and then sent out through the nozzle. However this type of valve becomes easily clogged when the dispenser is used for pasty products as those mentioned above. This implies a poor reliability and the need for a frequent maintenance to clean the seats of the balls from the deposits of detergent. A more effective type of valve is disclosed in US-A-6,092,695 showing a liquid dispensing cartridge pump with check valves formed of flexible membranes having apertures which close against conical projections on rigid disks. However, these valves are designed for liquids, therefore they are not as effective for pasty detergents. Therefore the object of the present invention is to provide a dispenser which is free from said drawbacks. This object is achieved by means of a dispenser having two one-way valves specifically designed for pasty detergents. Such a dispenser, which presents furthermore all the features of the preamble of claim 1, is disclosed in document US-A-3 211 340. The dispenser of the invention is defined by the combined features of claim 1. Other advantageous features of the present dispenser are disclosed in the dependent claims. The main advantage of the present dispenser is to combine the tightness of the double one-way valve system with the reliability stemming from the use of uncloggable valves. A second advantage is given by the fact that said valves are simple and cheap to manufacture and do not require significant modifications of the dispenser with respect to the conventional liquid soap dispenser. Further advantages and characteristics of the dispenser according to the present invention will be clear to those skilled in the art from the following detailed description of an embodiment thereof, with reference to the annexed drawings wherein: Fig.1 is a vertical sectional side view of the present dispenser; Fig.2 is a view similar to the preceding one of the dispenser in the detergent delivery phase; and Fig.3 is a view similar to the preceding one of the dispenser in the phase of load of the detergent from the container. With reference to fig.1, there is seen that the present dispenser is provided with a socket A for introducing the detergent container. This socket A may be made in various known ways, e.g. threaded, bayonet-like, snap-in, etc. The container (indicated by the dashed lines) has a spring-loaded sliding plug B, integral with an internal valve C which closes some openings D formed on top of the container. When the container is placed on the dispenser, a peg F located at the center of socket A pushes upward plug B and valve C thus allowing the downflow by gravity of the detergent through openings D. The detergent first passes through a ring of holes E and fills the space between socket A and a first membrane M which is substantially U-shaped and provided with a central bore closed by a conical shutter N, as better shown in the enlarged detail. The membrane M and shutter N together act as inlet valve to the underlying chamber G which communicates through a duct H with a small pump P located on the front of the dispenser. A return spring S is arranged inside pump P, which is operated through a button T whose travel is defined by an adjustable stop R. In practice, member R may be mounted on button T in two or more different positions, so as to change the travel of button T and therefore the amount of dispensed detergent. Through a ring of holes X formed in the bottom of chamber G, the detergent fills the space between chamber G and a second membrane V which is substantially U-shaped and provided with a central bore closed by a conical shutter Z, as better shown in the enlarged detail. The membrane V and shutter Z together act as a detergent outlet valve, same as the inlet valve. In the light of the above description and with further reference to figures 2 and 3 (where button T has been omitted) the operation of the present dispenser is readily understood. When pump P is pushed by overcoming the resistance of spring S, the detergent contained in chamber G can not flow upward to the container because the top membrane M is abutting against shutter N. The pressure created in the chamber therefore causes the deformation of the bottom membrane V, in particular at its thinner horizontal portion W. As a consequence, membrane V moves away from shutter Z and the detergent is dispensed through a small cylinder U acting as delivery nozzle. Once the pre-established amount of detergent has been dispensed and the pressure in chamber G has decreased, membrane V elastically returns to its rest position of fig.1. During this return movement the top internal edge of the small cylinder U abuts against the conical surface of shutter Z (see detail of fig.1). In this way the residual film of detergent possibly remaining on shutter Z is cut and a perfect tightness is achieved without risk of dripping. It should be noted that, in order to provide a greater effectiveness to this cutting and sealing action, the central portion of the membrane is thicker so as to have a greater rigidity. The return motion of pump P under the action of spring S causes a vacuum in chamber G, in which however the air can not enter from outside since the bottom membrane V, and in particular cylinder U, abuts against shutter Z. As a consequence, it is the top membrane M, in particular at its thinner horizontal portion L, which is deformed and moves away from shutter N thus allowing the inflow of detergent through the bore formed in the central portion K. Same as described above, also in this case membrane M elastically returns to the rest position, with the central portion K abutting against the conical surface of shutter N (see detail of fig.1) thus achieving a perfect seal. In practice the two one-way valves operate in the same manner and are different only in some dimensional detail and in the material of which they are preferably made. Some dimensions of a working prototype built by the applicant are indicated hereunder for exemplificatory purposes. More specifically, both the top shutter N and the bottom shutter Z have a conicity of 50°, while the corresponding bores which they enter have a diameter of 7 mm and 6 mm respectively. Furthermore, the two membranes are obviously different for the presence on the bottom membrane V of nozzle U which extends for 8,5 mm below the horizontal portion W. For the rest the two membranes have the same size and thickness, in particular a minimum thickness of 0,4 mm in the horizontal deformation portions L and W, a maximum thickness of 1,3 mm in the central portions K and U abutting on the respective shutters N and Z, and an intermediate thickness of 0,9 mm in the other portions of the membrane. A further difference between the two membranes is the material of which they are preferably made, since they operate in two different enviromnents. In fact while the top membrane M is completely immersed in the detergent and therefore more subject to the chemical aggression, the bottom membrane V is in contact with the detergent only on the inner face and is therefore less subject to aggression. As a consequence it is preferable to use for the top membrane M a low-density polyethylene (LDPE) which better resists the detergent without excessively swelling. On the other hand it is preferable to use for the bottom membrane V a thermoplastic elastomer (TPE) with an olefinic base, which having a greater elasticity provides a quick closing of the valve upon delivery without allowing the inlet of air from outside. It is clear that the above-described and illustrated embodiment of the dispenser according to the invention is just an example susceptible of various modifications. In particular, the shape and size of the membranes and shutters may be somewhat changed according to specific manufacturing needs, even differentiating the inlet valve from the outlet valve. Moreover, the materials used for the membranes may be different from those mentioned above, as long as they have adequate properties of elasticity and resistance to the detergent.

Claims: Dispenser for pasty detergents, including a socket (A) for introducing a detergent container, a chamber (G) in communication with said socket (A) through a one-way detergent inlet valve and with the outside through a one-way outlet valve, a pressure and a vacuum being alternately created in said chamber (G) through a pump (P) provided with a return spring (S), each of said one-way inlet and outlet valves consisting of a membrane (M; V) made of an elastically deformable material, being characterized in that said membrane (M, V) of said valves is provided with above, and in that it further consists of a corresponding conical shutter (N; Z) suitable to close said bore, the elastic membrane (M; Z) being substantially U-shaped and the bore being formed in a central portion (K; U) having a rigidity greater than the rest of the membrane in order to provide a greater effectiveness to the cutting and sealing action of the valves with regard to pasty detergents. Dispenser for pasty detergents according to claim 1, characterized in that the membrane (V) of the outlet valve is provided with a small cylinder (U) acting as delivery nozzle and extending below the horizontal portion (W) of said membrane. Dispenser for pasty detergents according to one or more of the preceding claims, characterized in that the membrane (M; V) has a minimum thickness in the horizontal portions (L; W) of a value equal to about 1/3 of the thickness in the central portions (K; U) abutting on the respective shutters (N; Z) and equal to about 1/2 of the thickness in the other portions of the membrane. Dispenser for pasty detergents according to the preceding claim, characterized in that the thickness in the horizontal portions (L; W) is 0,4 mm, the thickness in the central portions (K; U) is 1,3 mm and the thickness in the other portions of the membrane is 0,9 mm. Dispenser for pasty detergents according to one or more of the preceding claims, characterized in that the conical shutter (N; Z) has a conicity of 50°. Dispenser for pasty detergents according to one or more of the preceding claims, characterized in that the membrane (M) of the inlet valve is made of low-density polyethylene. Dispenser for pasty detergents according to one or more of the preceding claims, characterized in that the membrane (V) of the outlet valve is made of thermoplastic elastomer with an olefinic base. Dispenser for pasty detergents according to one or more of the preceding claims, characterized in that the pump (P) is operated by the user through a button (T) whose travel is adjustable. Dispenser for pasty detergents according to the preceding claim, characterized in that the adjustment of the travel of the button (T) is achieved through a stop (R) which can be mounted on said button (T) in two or more different positions.

Inventors: NIADA GIANANDREA, NIADA, GIANANDREA
Applicants: QTS SRL, QTS S.R.L.
Application year: 2001
Main classification: A47K5
IPC codes: A47K5