Injection Moulding Machine for Vacuum Breakers and Anti-Siphon Valves
Vacuum breakers and anti-siphon valves are moulded on horizontal injection moulding machines, usually in multi-cavity moulds, from POM, PP, ABS or PA66. Cavity count, the projected area of the body and a small shot weight decide the machine size. The process point that matters most is a flat, flash-free seat and a round guide bore.
Machine selection for a vacuum breaker centres on a small, repeatable shot, steady holding pressure on the seat area and short residence time for POM. Pratishna Engineers supplies horizontal injection moulding machines for these valves and can suggest a setup to match your mould and cavity count.
Moulding Vacuum Breakers?
Send the valve drawing, body and poppet materials and monthly volume, and Pratishna Engineers will suggest a machine for each moulding.
Machine Requirements for Vacuum Breaker Moulding
Plumbing codes often treat a vacuum breaker as a backflow device, so its seat has to seal and its poppet has to slide freely every time. Check for:
- Flat, flash-free seat face with no sink behind it
- Round guide bore so the poppet or float slides freely
- Short residence time to stop POM degrading in the barrel
- Thread strength on PA66 or PP bodies taking fitting torque
- Small shot weight matched to a suitably sized screw
- Balanced runners in multi-cavity moulds for even part weight
Recommended Machine for Vacuum Breakers
Vacuum breaker bodies, poppets and caps are small parts, and the clamping force is set mainly by the number of cavities. Hybrid PH (120-140 T) machines, with electric injection, and the E Series (75-180 T) suit many of these moulds. Larger family moulds or high-cavity body tools move up to C Series (140-320 T) machines, or to the H Series (120-350 T).
Not Sure Which Machine You Need?
Share your vacuum breaker parts and mould layout for a machine recommendation.
Why Choose Pratishna Engineers?
- Application-Based Machine Selection
- In-House Engineering & Manufacturing
- Multiple Machine Series
- Production-Focused Solutions
- End-to-End Technical Support
- Industry-Specific Solutions
- Machine Lifecycle Support
Injection Moulding Machine Buyer Resources
Download practical resources to help you select, size and specify the right machine.
Horizontal Injection Moulding Machine Selection Guide
A step-by-step guide covering the key inputs needed to select the right machine: product weight, projected area, number of cavities, plastic material, required clamping force, shot / injection capacity, mould dimensions, production quantity, cycle time and automation requirement.
Download PDFPDF · 265 KB
How to Calculate Clamping Force for an Injection Moulding Machine
A clear methodology that explains how clamping force is calculated, covering projected area, injection pressure, safety factor, number of cavities and material considerations.
Download PDFPDF · 363 KBWater Treatment Components & Machine Guide
A guide to Water Treatment components, covering RO housings, purifier parts, filter housings, push-fit connectors, rotameters, saddles, distributor hubs and valve parts. It explains food-contact grades, pressure strength, sealing faces, and how to match each part to a suitable machine.
Download PDFPDF · 205 KB
FAQs / Buyer Questions
Questions buyers ask when they start moulding vacuum breakers and anti-siphon valves.
Which Injection Moulding Machine Is Used to Make Vacuum Breakers?
A horizontal machine at the lower end of the tonnage range covers the small bodies and poppets. E Series or Hybrid PH machines handle typical cavity counts, while C or H Series machines take larger family moulds.Is the Diaphragm or Seal Moulded on the Same Machine?
No. The diaphragm or poppet seal is silicone or EPDM rubber, made by a separate rubber moulding process and assembled later. The injection moulding machine makes the thermoplastic body, cap, poppet and guide.Why Does a Vacuum Breaker Leak or Stick After Moulding?
Leaks usually trace to sink, flash or a gate mark on the seat face. Sticking comes from an oval guide bore, often caused by uneven cooling around the core or low holding pressure on POM.
Which Material Suits the Body and Which Suits the Poppet?
PP or ABS is common for bodies, and PA66 where threads take installation torque. POM suits poppets and guides because it slides with low friction and holds its size. PA66 needs drying before moulding.Can Pratishna Recommend a Machine for My Vacuum Breaker?
Yes. Share the drawing or a sample of each part, the materials, part weights, mould size, cavity count and monthly quantity, and Pratishna Engineers will recommend a suitable machine.Does the Machine Suit Other Water Treatment Valve Parts Too?
Yes. Machines in this range also mould fluid connectors, saddle straps, dosing pump parts and purifier taps, with the final choice set by each mould and its cavity count.
Technical Disclaimer
Disclaimer: The information provided in this webpage is for general informational and educational purposes only. It is based on technical references and industry information available at the time of preparation and may be subject to change. It does not constitute engineering, technical, commercial or professional advice, nor does it constitute a quotation, specification, warranty or contractual commitment by Pratishna Engineers.
Actual injection moulding machine and process requirements vary according to the component design, material, mould, production volume, machine configuration and operating conditions. The information, examples, calculations and recommendations provided should be independently evaluated and verified for the specific application before making any equipment, process or production decision. Information obtained from third-party sources remains subject to the accuracy and limitations of those sources.
Limitation of Liability: Pratishna Engineers makes no representation or warranty, express or implied, regarding the completeness, accuracy or suitability of the information for any particular application. To the extent permitted by applicable law, Pratishna Engineers shall not be liable for any loss, damage, cost or consequence arising from reliance on or use of the information contained in this webpage. Final machine selection, configuration and application suitability should be confirmed with Pratishna Engineers based on complete and accurate project requirements.
Talk to Our Engineers
Planning a New Injection Moulding Project?
Share your component, material, mould and production target. Our engineering team will help you identify the right machine configuration.
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