Every additional valve in the hydraulic circuit will mean more piping, fittings and potential leak points. With technology becoming smaller, hydraulic circuits have become complex with more functions in a smaller space.

Cartridge valve manifolds have been developed to overcome this. The manifolds contain multiple valves and each element is one third the size of a conventional valve element. The valves are mounted within the manifold block.

This reduces space, piping, leak points and effort when designing. This article will explain the basics of cartridge valve manifolds and what should be explained to a customer when specifying. It will also explain what should be discussed when speaking to a potential manufacturer.

Cartridge Valve Manifolds – Space Saving

How are cartridge manifolds different to conventional manifolds?

| Feature | Conventional Piped/Subplate | Cartridge Valves |
| Mounting | Individual valve bodies | Plates/lines | Cartridge Elements in block cavity |
| Piping | More hoses/pipes/fittings | Less piping |
| Space | Larger system | Smaller space |
| Leak Points | More joints | Fewer joints |
| Effort | Less as standard parts | More as block is bespoke |
| Ideal for | Simple/Low function circuits | Complex/Space saving circuits |

Manifolds in general simplify the design and reduce the number of leak points. However, if the design effort and cost is acceptable. If there aren’t many functions in you circuit it might be best to go for standard parts. If there are multiple functions, the standard parts may be too large and cumbersome.

What are the main types of cartridge valves?

Slip-in (2 port) Cartridge Valves

Insert into cavity. ISO 7368 standard defines the geometrical characteristics of the 2 port slip-in cavities. This ensures interchangeability between different manufacturers. This doesn’t define rated pressures so just because the cavity meets ISO standard it doesn’t mean it will be able to maintain integrity under the design working pressure. This needs to be validated in the design and testing process.

Screw-in Cartridge Valves.

Insert into block using a screw thread. ISO 7789 defines the cavities of 2/3/4 port screw-in cartridge valves for industrial and mobile equipment. These are ideal for low flow rate compact functions.

As a rule of thumb, slip-in cartridges will generally be selected for higher flow control and logic functions. Screw-in cartridges will be chosen for smaller functions and flows. Other factors such as flow, pressure and response should be considered when deciding on your final valve.

When should you consider using a cartridge valve manifold?

Consider using a cartridge valve manifold if:

• You have limited space (mobile equipment/compact machine tool)
• You have a circuit with multiple functions (multiple pressure levels, sequencing, regeneration etc)
• You want to reduce leak points and have a cleaner system
• You are producing repeated OEM quantities and you can spread the cost of bespoke block design across multiple units.
• Maintenance is a concern (cartridges can easily be replaced without having to break any piping).

What should you give to your manufacturer to finalise your design?

Having a clear specification will save a huge amount of time. Ensure you give:

• A circuit diagram (hydraulic schematic). This should show all the functions.
• Working pressure and flow. Include any transient conditions (peak flow).
• Fluid type and working temperature.
• Cartridge valve make/model or cavity standard.
• Port type, size and material.
• Mounting and size limitations.
• Material and finish requirements. Corrosion protection.
• Testing requirements and documentation.
• Annual quantity and delivery schedule.

What affects the performance?

• Passage design and size. Sharp bends and small passages will cause restrictions.
• Cavity machining. Poor tolerances can cause leaking and sticking.
• Material (block material must be compatible with pressure, fluid and surrounding conditions. The Teutonic manifold page lists shear strength, corrosion resistance, and other features.)
• Cleanliness (burrs and debris cause damage to valves)
• Serviceability (cartridges should be placed to be accessible and removed without dismantling the machine)

What factors should you consider when choosing a manufacturer of Hydraulic Manifolds in India?

Price isn’t always the only consideration. When looking at manufacturers of hydraulic manifolds in India consider:

• Design capability. Can they advise on improvements to your circuit or do they just machine to your design?
• Machining capability. Do they have CNC capability? Can they achieve cavity tolerances?
• Testing capability. Do they do dimensional checks, pressure testing and fluid contamination?
• Material certificate. Do they provide a certificate of traceability?
• Bespoke capability. Can they produce one off prototypes?
• Delivery time. Can they give a realistic delivery time?
• Complete system. Can they supply all the components (cils and valves).

Teutonic Engineering Pvt. Ltd from Coimbatore. Founded in 2002. Provide hydraulic cylinders, power packs and manifolds. Local hydraulics store and engineering company.

FAQ

1. What is a cartridge valve manifold

It is a machined block that contains cavities and passages. This replaces a large proportion of piping and simplifies the design.

2. What is the difference between slip-in and screw-in cartridge valves?

Slip-in cartridge valves use a cover and threaded screw-in valves. They follow different standards. Slip-in cartridges follow ISO 7368 and screw-ins follow ISO 7789.

3. Will a cavity to standard guarantee pressure rating?

No. ISO 7368 states it is a cavity to standard and does not define pressure rating. The pressure capability should be validated in the design of the block, material used and testing.

4. When would you choose a cartridge manifold over a conventional manifold?

If you have multiple functions, limited space and less leak points required. This would generally be used for repeated OEM volumes. If you have a simple circuit it may be more economical to go for conventional (reservoir style) valves.

5. What should I provide to a manufacturer when developing a new product?

You should provide a hydraulic schematic, fluid type, pressure and flow requirement, type of valves, space available, finish required, quantity expected and your testing requirements.

6. Can manifolds be bespoke?

Yes. Manifolds are often designed to fit exactly with individual equipment. According to Teutonic’s website they manufacture bespoke manifold solutions.

7. What should OEM purchasers look for when choosing a manifold supplier?

Look for a supplier who can manufacture hydraulic components and provide associated parts. Look for a supplier who can help with design, have a short lead time, can Computer numerical control (CNC machine) and pressure test. They should have a clean environment to allow traceability of lots.

8. Can manifolds be manufactured for hydraulic power packs and cylinders?

Often manifolds will be integrated with power packs and cylinders. Ask your supplier.

Conclusion :

The basic principle behind cartridge valve manifolds is to sacrifice some design complexity for a space saving, cleaner system with less leak points. They will generally pay off on complex or space saving machines and high volume OEM business. Remember that cavity to standard does not define pressure rating, it defines geometry when specifying.

When selecting a hydraulic manifold manufacturer in India look for design, machining and testing capability. If you need to design a new hydraulic circuit or change an existing piped valve bank the Teutonic team will review your drawing and pro.