In a valve system, a control fluid is distributed to various control valve units which each control a flow of a specific process fluid. Typically, compressed air is used as the control fluid, whereas the process fluid may be a liquid or a gas.
The control valve units used in the prior art comprise an inlet for the process fluid, via which the process fluid can be delivered to the respective control valve unit. Further, each control valve unit comprises an outlet via which the process fluid can flow out of the corresponding control valve unit and be supplied to e.g. an analyzer where it is examined. In each control valve, a valve is usually arranged which controls the flow of the process fluid through the control valve unit. The control fluid which is distributed via the valve system to the individual control valve units is used for controlling the valves. The valve may be designed as a membrane valve, for example.
From DE 10 2013 104 688 A1 for instance, there is known a valve system comprising such control valve units in which a process fluid acts as a control fluid for the other process fluids.
Other valve systems known from prior art are distinguished in that the valve system itself is acted upon only with the control fluid and is configured for its distribution, whereas the process fluid flows only through the corresponding control valve units. i.e. the connected process valves. Such a valve system is known from WO 99/54632 A1, for instance.
A modular valve system comprises several separate valve modules which can be set in fluidic communication and each may have several control valve units. The modular design enables to expand the valve system by the addition of further modules of identical construction and hence to adapt it to the requirements of the user, in particular with regard to the available ports. The individual valve modules each have internal control fluid lines, so that the individual control valve units can be supplied with the control fluid. Two neighboring valve modules are usually connected to each other via control fluid lines which emerge at the neighboring sides of the valve modules at openings which are in alignment in the assembled state, to form a continuous control fluid connection.
In these modular valve systems, it has turned out to be disadvantageous that the control fluid lines and the process fluid lines have to be sealed at the interfaces between the individual valve modules, requiring higher mounting expenditures. Further, the known valve systems have turned out to be disadvantageous to the effect that they are not easy to service, as the ports have to be pulled off from the control valve units during their maintenance, in particular in case a valve module is to be replaced.
It is the object of the invention to provide a valve system which is of simple construction and maintenance-friendly.