Our wide product range catering to a variety of needs.
Valves by John Valves
We’ve been manufacturing and supplying valves to Australia and New Zealand since 1896. Our wide product range consists of a variety of types of high-quality valves. We appreciate the uniqueness of every project. Thus, we also provide the option for custom-made speciality products to order.
These linear motion valves are used to stop, start and control the flow of fluid. Unlike the perpendicular seating in gate valves, globe valve seating is parallel to the line of flow. All contact between seat and disc ends when flow begins. This provides the valve with effective throttling ability for flow regulation.
The check valve, also known as a non-return valve, is used in piping systems to restrict and stop backflow. The fluid that passes through a pipeline creates pressure and flow velocity that opens the valve. On the flip side, the reversal of flow will cause the valve to close. There are a variety of valve types depending on the requirements of your system.
These types of valves, commonly used in process plants and water systems, are linear motion valves used to start or stop the flow of fluid or gas. In operation, gate valves are either completely open or completely closed. They allow for a minimal pressure drop as the fluid passes through the valve. This is due to the gate valve being removed from the flow when it is fully open, creating no resistance.
Gate valves, while not designed for throttling or too-frequent operation are generally ideal for services requiring full flow or no flow applications.
These valves work as safety devices, protecting pressurised equipment or systems during an overpressure event. If the pressure increases beyond what the equipment or piping system is designed to handle, damage can occur to the system itself, as well as personnel and property.
The primary purpose of safety and relief valves is to vent gas or fluid from a system that has become over pressurised, preventing the risk of damage and injury.
Air valves are designed for use in water systems and are available with either a small or large orifice. Valves can also be supplied with a combination of both a small and large orifice.
Small orifice air valves automatically release air that accumulates in pipelines during normal operation which can form large pockets of air at the high points in the piping system. These large pockets of air, if left to form, can seriously impede flow and result in increased pumping costs. Large orifice air valves on the other hand allow for the automatic ventilation of the pipeline during filling and emptying operations.
These valves derive their name from the wing-like action of their discs, which operates at right angles to the flow. The main advantages of a butterfly valve are low cost, quick operation, easy installation and light weight for size ratio.
These valves can be used in fully open or fully closed positions. They can also be used as a low cost way to control the flow of liquids or gases. However, they are not considered to be accurate control valves.
A ball valve is a valve with a spherical ball inside the valve body. The sphere has a hole through its middle so that, when in line with both ends of the valve, the flow will occur. When the valve is closed, the hole is perpendicular to the ends of the valve and flow is blocked.
Ball valves are used extensively in industrial applications due to their versatility and ease of repair and quick operation.
These simple and economical valves consist of cylindrical or conically-tapered plugs which can be rotated inside the valve body to control flow. The plugs in these valves have one or more hollow passageways going sideways through the plug, allowing flow when the valve is open.
Parallel Slide Valves
These valves consist of two discs which maintain contact with the parallel body seats with a light spring. It uses line pressure to effect a tight closure. Temperature changes in the line are accommodated by the flexibility of the disc assembly and therefore do not affect the operation of the valve.
When being opened or closed, the discs slide across the seat faces, helping to remove any direct and foreign matter from the seating faces.
Level Control Valves
Level control valves are recommended for end-of-line service to keep water tanks full. They also eliminate the hammer and chatter associated with conventional ballcocks.
Knife Gate Valves
Knife gate valves are used to slice through sludge or sewerage. It is distinguished from the standard gate valve design by the use of a simple metal plate for the gate. They generally have a chamfer on the gate edge to help with cutting through product.
This uni-directional or bi-directional valve is used for pressure-tight isolation of solid-liquid mixes in general industrial service applications.
Named after their sharp needle-like disc and matching seat, needle valves design allows for precise throttle control in small piping systems.
Our dreadnought fig BDV blowdown valves are suitable for attachment to all types of boilers for continuous or intermittent use to drain dissolved solids from the boiler water. They are fitted with a stainless steel ball and reinforced PTFE seats with a quick quarter-turn action to open & close.
Gauge Cocks are designed for connecting pressure gauges to a boiler or syphon. They are also suitable for connecting vacuum gauges.
Pressure Reducing Valves
Sometimes the pressure generated by boiler, pump and compressor systems are too high for the process equipment downstream. Pressure reducing valves are used to create a consistent flow at a more suitable pressure level.
Penstocks provide an efficient and economical means of flow control in all open channels, dam walls or similar applications. They are an ideal choice for controlling flow in irrigation channels, water and sewerage treatment plants and flood control systems.
These devices are used to discharge condensate and non-condensable gases with a negligible consumption or loss of live steam. Most steam traps are nothing more than automatic valves. They open, close or modulate automatically.
The purpose of these valves is to stop particles from passing through a pipeline and damaging sensitive equipment. They do this by employing a perforated mesh straining element.
The use of a y-strainer results in minimal pressure drop.