The most important valve types

and their functions

Control and regulating valves are absolutely necessary in systems with positive displacement pumps for safe and efficient operation. While the delivery rate of a centrifugal pump is set according to the system operating pressure, the positive displacement pump delivers delivery rate defined by the displacement and speed, almost independent of pressure (only influenced by the compressibility of the medium to be pumped at higher delivery pressures). In the event of changing flow rates, by switching consumers on and off in the high-pressure system (e.g. by closing spray guns or nozzle heads), the system pressure would suddenly lead to overpressure without corresponding valves and thus to a defect in the high-pressure system. To reliably prevent this, every high-pressure system needs safety and work valves.

At a glance:

The high pressure valve functions

for the high pressure technology

  • Safety valves: prevent an impermissible increase in pressure (by opening when the operating pressure is exceeded) and close again reliably and tightly after the pressure is released.
  • Bypass valves: the pressure line in the direction of the suction line is opened. This allows the pump to start up without pressure and switch over to pressureless circulation.
  • Consumer shut-off valves: Consumer lines are switched on and off against high pressure.
  • Overflow valves: Allow excess volume to flow out without pressure and keep the operating pressure in the system constant.
  • Shut-off valves: Used to shut off consumer lines against suction or circulating pressure.
  • Pressure maintenance valves: Keep the system pressure constant in multi-consumer operation when individual consumers are shut off.
  • Check valves: Prevent the pumped medium from flowing back.
  • Changeover valves: Used to control two consumers alternately (3/2-way valve).
At a glance:

High pressure valves and their characteristics

for high pressure technology

High-pressure valves have many properties, some of which can be combined with each other. Our high-pressure technology valve specialists will be happy to advise you.

  • Explosion protection: Suitable for operation in potentially explosive atmospheres (ATEX).
  • Cascadable: Allows several valves to be linked together to form a complete valve station.
  • Deionized water: Suitable for operation with demineralized water.
  • Seawater: Suitable for operation with seawater.
  • Silicone-free
  • Gap seal: Serves to ensure exact reproducibility of the set pressure.
  • Electro-pneumatic control: Adopts the switching command and pressure adjustment of the valve.
  • Position sensing: Continuously detects the current position of the valve.
Control and regulating valves

Classification into various valve subgroups

According to their function and intended use

Control and regulating valves are used in systems with positive displacement pumps to ensure operational reliability and efficiency. Control valves are available in various types and designs. According to their function and intended use, they are divided into various subgroups as follows.

The bypass valve is installed parallel to the consumer line. It opens the pressure line in the direction of the tank or suction line or return line and allows the pump to start up without pressure. It is also possible to switch over to pressureless circulation.

A pressure maintaining valve is installed directly in the consumer line. Both the inlet and the outlet can be fully pressurized. The pressure maintaining valve is used to maintain a certain system pressure in the consumer line upstream of the pressure maintaining valve, largely independent of the volume flow that the consumer consumes. The pressure maintaining valve makes it possible to keep the system operating pressure constant when connecting and disconnecting further consumers.

The check valve is installed directly in the consumer line and it is used to prevent the flow medium from reversing direction. Thus, a check valve ensures that the flow of the medium passing through it flows in only one direction. Due to the springing, this valve causes a pressure loss. Both the inlet and the outlet can be fully pressurized.

An overflow valve allows partial quantities of the pumped medium to flow out without causing the pressure in the system to drop or rise. This means that the operating pressure in the system is kept largely constant and is essentially independent of the volume flow through the overflow valve. Furthermore, an overflow valve enables multi-consumer operation and small-consumer operation even with larger pump flows that cannot be controlled. Overflow is possible in continuous operation.

A shut-off valve is a fitting for the controlled opening or closing of pipelines. It controls the inlet, flow or outlet of fluids in a fluid line. The consumer shut-off valve is installed directly in the consumer's piping, with both the inlet and outlet fully pressurized. The challenge here is that the consumer shut-off valve must still be tight after many thousands of cycles.

A closing valve is a fitting with which a pipeline can be kept closed up to a valve-specific nominal overpressure. The closing valve is installed directly in the consumer line and can be fully pressurized at both the inlet and outlet. A closing valve opens automatically when the nominal closing pressure is exceeded and differs in this respect from a shut-off valve. The discharge of the pumped medium is prevented by the closing valve for consumers without their own closing device during the pressureless circulation operation of the pump.

A safety valve is installed parallel to the consumer line and, as the name suggests, serves to protect the pump and, if necessary, the system against overpressure. The safety valve should not respond during normal operation. A safety valve responds when the pressure at a pump or system exceeds the preset value.

The changeover valve is installed directly in the consumer lines of the consumers. Both the inlet and the outlet can be fully pressurized. The changeover valve is used for fast switching between several consumers and must still be tight even after many thousands of switching operations.

Why URACA valves?

URACA has been known for decades for the highest quality in the construction of high-pressure positive displacement pumps and high-pressure valves. In order to consistently meet this requirement, URACA in Bad Urach develops and manufactures highly reliable and durable valves for small to very large flow rates and system pressures of over 3,000 bar.

On the one hand, we can serve a multitude of necessary and meaningful individual functions, on the other hand the uniquely broad spectrum of valve types also covers many combinations of functions. This allows systems and plants to be built in a much more compact, efficient and cost-effective manner.

As a further special feature, URACA valves offer maximum personal safety for the operator. Switching positions can be reliably and precisely queried and evaluated in the system control. Depending on the valve type, it can be used in potentially explosive areas up to zone 2. Highest material quality allows the use with different media and medium temperatures.

Almost all URACA switching valves can shut off a consumer line reliably against full operating pressure without auxiliary energy. Cascadable URACA valves can be assembled extremely compactly to form a valve station.

Find out more now.