Patent Application
20120132835
The present application claims the benefit of priority of German Application No.102010062195.1, filed Nov. 30, 2010. The entire text of the priority application is incorporated herein by reference in its entirety.
The disclosure relates to a control valve for pressure reduction, in particular for liquids containing solids.
A control valve of this nature is known, for example, from DE 11 2005 000 683 T5. It comprises two chambers with inlet and outlet and a channel connecting the two chambers, which is closed off by a partition device—here a membrane under pressure from a spring. When the pressure of the product in the inlet is greater than the pressure from the spring, the partition device opens a small gap in the channel and the liquid can flow into the discharge chamber. On flowing through the gap the pressure of the liquid is reduced over a very short distance. When valves of this nature are employed in food technology for liquid foodstuffs such as soft drinks, teas or juices which include solid constituents, for example fibers, juice sacks or fruit cells, these solid constituents are subjected to high mechanical shear stresses on passing through this gap, which can result in impairment of the quality or taste of the product.
One aspect of the disclosure is therefore to make a control valve available, which can be employed particularly in the foodstuffs industry for liquids containing solids, such that it ensures in a simple and gentle manner that the increased pressure on the product is reduced with as little mechanical stress as possible.
According to the disclosure this is achieved with a generic valve in that the connecting channel is formed as an elastic through-flow channel with a free line cross section, which can change—in particular however it can be reduced—along its longitudinal axis over an expanded line section.
If a product subjected to high pressure flows through the reduced line cross section of the through-flow channel formed as an expanded line section, the flow velocity of the product increases due to volume conservation, whereby a purely physical pressure reduction can be achieved. The pressure reduction of the product however occurs gradually over the extended line section, whereby the mechanical stress for the product can be kept low due to the long through-flow line cross section in the through flow channel. Due to the large free cross section of the line carrying the product, the shear stress of the product can be significantly reduced.
Preferably the control valve can comprise a housing in which the inlet, outlet and the channel are arranged, whereby the channel connects the inlet and the outlet. The channel is formed as an elastic through-flow channel which is coupled to the normal product line. In this way a stable mounting and a reliable interaction of the components of the control valve is achieved.
In a further preferred embodiment a control piston, extended along the longitudinal axis, is arranged on the control valve, which can be moved by at least one, preferably two, variable speed drives, which can be arranged on the housing. Control of the variable speed drives can be provided by a controller.
In a further preferred embodiment at least two control pistons, extended along the longitudinal axis, are arranged on the control valve. Each control piston can be moved independently of the others with the aid of at least one variable speed drive. Control of the variable speed drives can be provided by a controller. Due to a plurality of control pistons of this nature the piston area which becomes effective can be varied and adapted to the product.
Preferably the control pistons are movable in a direction vertical with respect to the through-flow channel. During the movement of one or a plurality of control pistons at least also in the vertical direction relative to the through-flow channel the piston area interacts with the elastic through-flow channel and the housing, so that the free line cross section of the through-flow channel is modified. Movability in the vertical direction is taken to mean that at least part of the control piston is movable at least also in the vertical direction opposite the longitudinal axis. In this respect a movement may also be involved which is diagonal with respect to the vertical direction or a pivoting movement with respect to a specific axis may be involved. It would however also be possible that the control piston acts on a further element, say a membrane, and presses it against the through-flow channel. In this case the membrane can also be used for the dynamic sealing of the through-flow channel and may thus also be a constituent part of it.
The use of a single control piston represents a simple and economical method of changing the free line cross section of the through-flow channel. By using a plurality of control pistons however a specified cross-sectional profile can be impressed in the through-flow channel. Thus it is for example possible to define a cross-sectional profile such that it is matched to a certain product solid-body size.
In a further advantageous embodiment the control valve is designed such that the line section has an internal diameter of 16-130 mm. In particular a minimum internal diameter of more than 16 mm is used so that on one hand the free line cross section is sufficiently large and variable and on the other hand the volume flows required for production are achieved.
In a further advantageous embodiment the control valve is designed such that the line section has a length of up to 0.3-3 m. In particular the line section has a minimum length of more than 0.3 m so that the product pressure is reduced over a sufficiently long run.
In a further advantageous embodiment the control valve is designed such that a pressure reduction of the product of up to 10 bar can be obtained. The control valve is used here especially for the reduction of pressure differences of 1.5 bar and more.
brief description of the drawings
In a further advantageous embodiment the control valve is designed such that it can process a volume flow of up to 90 m3/h. The control valve is used here especially for the processing of volume flows of 1 m3/h and more.
Further advantages and embodiments emerge from the enclosed drawings. These show:
The control piston 8a has a stamp-shaped body with a flat piston area 10 on its underside which is arranged orientated to the through-flow channel. The control piston and the piston area can also have a different shape however which is suitable for acting on the through-flow channel. Furthermore, it is also possible that a spring acts upwards against the gravitational effect on the control piston, i.e. the spring pressure presses the control piston away from the through-flow channel. It is only that the movement of the control piston presses the piston area 10 against the through-flow channel 5, whereby together with the housing 2 a force on the through-flow channel 5 is exerted which compresses the through-flow channel in the vertical direction. Correspondingly, the free line cross section is restricted.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102010062195.1 | Nov 2010 | DE | national |
