Artificial Intelligence Helps Select Valves
The range of hydraulic valves in terms of function, size, and performance is vast. Selecting the right valve can be challenging and often requires extensive experience and in-depth knowledge of both the available products and hydraulic systems. Hydnet is now launching an AI assistant that combines general hydraulic expertise with a large database of valve information to answer questions about the products.
This enables customers to learn more about the products and make better system design decisions. Fluid Scandinavia conducted several tests with different questions, and below is a good example of how Pascal can assist with both education and sizing.
Question:
Explain to me what a cavity is and which standards and sizes are available.
Cavity – The Basics
A cavity is the machined hole in a valve block into which a cartridge valve is screwed. The cavity has a highly precise geometry consisting of threads, sealing grooves, guide surfaces, and annular grooves that correspond to the valve ports (port 1, port 2, port 3, port 4, etc.).
For a cartridge valve to function properly, the cavity in the block must exactly match the valve’s cavity designation. This is why the cavity designation is always a critical factor when selecting both the valve and the manifold.
How a Cavity Is Constructed
A typical Sun cavity consists of:
- Thread at the top that holds the valve in place
- Sealing surfaces with O-rings between the port grooves
- Annular grooves – circular recesses where oil can flow radially in and out
- Bottom port – for axial connection (often port 1 on seat valves)
The number of annular grooves determines how many ports the valve can have (2-way, 3-way, or 4-way).
Common Cavity Standards
Several standards exist on the market:
Sun Hydraulics Floating-Style Cavities (T-Series)
Sun uses a patented “floating” design in which the valve body can move slightly within the cavity. This minimizes deformation stresses and provides longer service life. Designations begin with T- followed by a size number.
SAE / Industry Standards
Many manufacturers follow SAE standards or common industry practices, such as 7/8-14, 1 1/16-12, and 1 3/16-12 UNF threads. These are often interchangeable between different manufacturers (but not always—always verify with the data sheet).
Sun Hydraulics – Common Cavity Sizes
Sun cavities are the most common in Hydnet’s product range. Typical sizes include:
2-Way Cavities (2 Ports)
- T-8A – small, up to approximately 30 l/min
- T-10A – medium, up to approximately 60 l/min
- T-11A – larger, up to approximately 120 l/min
- T-17A – high flow, up to approximately 240 l/min
- T-19A – very high flow, up to approximately 480 l/min
- T-21A / T-23A – industrial high-flow applications
3-Way Cavities (3 Ports)
- T-8A → T-13A → T-162A, etc. (same sizing principle, additional annular grooves)
4-Way Cavities (4 Ports)
- T-21A, T-31A, and others
As a general rule: a higher number indicates greater flow capacity. The letters A, B, C, etc. indicate the number of ports or cavity variant.
Practical Application
- Select a cartridge valve based on function, pressure, and flow requirements.
- The valve model code specifies the cavity (for example, CBCA-LHN = T-11A cavity).
- Select a manifold with the matching cavity (sandwich manifold, line-mount manifold, etc.).
- Port connection sizes (G1/4″, G1/2″, etc.) are selected separately based on the piping system.
