Gate Valves

Gate valves in cast steel, bronze, iron and Stainless, Sluice Valves, Parallel Slide Valves, Knifegate Valves from Australian Stock.

Gate valves in cast steel, bronze, iron and Stainless, Sluice Valves, Parallel Slide Valves, Knife gate Valves from Australian Stock.

Gate Valves are still the most popular of all the valve styles across the market. Some of their applications in recent years have been replaced by ball and butterfly valves. They operate by lifting the gate or wedge by linear or cam action. Gate valves exist for on / off application. In the majority of applications It is best practice to have these valves fully closed or fully open. Apart from some very special slurry designs / applications they should not be used in any sort of throttling. The majority of gate valves right up until the 1980s were metal seated. With the advent of technology particularly in waterworks applications these can be soft seated via an encapsulated rubber wedge-gate.

The advantage of the gate valves are their cost (although dearer than butterfly valves) they give full unobstructed flows. They are available in standard handwheel or quick acting styles. They are easily fitted with the various types of electric / pneumatic / hydraulic actuation. The gate valve family covers the traditional style through to knife-gate, parallel slide, sluice, penstocks and weir gates. They can be in Plastic, brass, cast iron, cast / forged steel and stainless steel.

Sizes available from 15nb to over 2000nb. Pressure ranges from 125psi to the power station varieties to class 2500 (over 6000psi). End connections are typically threaded, flanged, socketed, buttweld and semi-wafer. The range is comprehensive and the majority is carried in stock Australia up to 600nb.

Knife Gate Valves

Most knife gate Valves are unidirectional (i.e. designed to flow and seal in one specific direction only) and are rising spindle. A Bi-directional valve will seal in either flow direction. A non rising spindle means you do not have to account for addition height for that spindle to rise allowing the valve to open. A non rising design allows for easier installation in valve pits or where adjacent pipework or structures could foul against the valve. Neither handwheel or spindle rises. The BR-C (data sheet below) has saved many a contractor where pipework design failed to give the valve operation a thought.

A step up from the general purpose knifegate valves are units designed for slurry service. The 6S with its ease of construction is one of if not the best maintance friendly slurry valves on the market. The 6S is for pressures up to 10 Bar comes handwheel operated as standard with various actuation options in sizes from 50nb to 400nb.

Petrochemical – Marine – General Service Gate Valves

Petrochemical Valves are available in Flanged, screwed, socket-weld and buttweld connections. They will conform to international API and ANSI standards most commonly manufactured in Steel and stainless steel. These types of Valves are used across a range of services in the industry and are now also the most popular in general steam applications on boliers and steam distribution lines. The majority of gate valves will have a packed gland however bellows sealed are gaining popularity.

General Industrial Service gate valves can be of Cast iron, Steel, Stainless and Bronze materials. They can be to manufacturers standard or BS / AS local standards. Applications can be plumbing, HVAC, in chemical, water or low pressure steam service. These valves are Flanged or screwed only.

MARINE Valves are specific for that industry manufactured from ASTM B62 and ASTM B148 (Bronze and NI Bronze) materials.

Forged steel valve small bores DN10 to DN50 range Class 800 / 1500 includes flanged ANSI 150 ANSI 300 and ANSI 600

Cast steel Range ANSI 150 to ANSI 1500 flanged valves

Stainless steel quick acting gate valves bronze quick acting gate valves

New to the range of quick acting gate valves are the STAINLESS STEEL body units from 1/2″ DN15 through to 4″ DN100. These units are more suitable for corrosive environments / media or in some HVAC / plumbing applications where brass is not permitted by local by-laws.

Parallel Slide Valves

Parallel Slide Valves offer excellent sealing capabilities far beyond the conventional wedge gate valve due to their discs operating independently to the stem thrust forces. Due to their design they handle temperature variations both hot and cold without binding or sealing issues that normal gate valves suffer from. They initially came about as a result of steam applications in the 1800’s in the UK and are commonly used in the smaller sizes in bronze or steel as boiler blowdown valves with quick acting levers. Nowadays they are also made in the exotic stainless steels for additional pressures and temperatures found in our modern power stations. Sizes 40nb to 300nb are usually handwheel operated while larger sizes and pressure ratings are actuated.

We have these valves out in steam services in Australia installed since the 1970’s still in service without maintenance. If they do need maintenance ever it is usually on the discs which can usually be polished and reinstalled quickly. As an example a standard gate valve would have been replaced 7 times (they are not repairable) over that period. Any “steam man” would install a parallel slide valve as a main steam stop / distribution line or blowdown valve. The higher initial cost over a standard gate valve is insignificant to its reliability and lifespan. We cover the whole range of these valves and cannot recommend them high enough.

For the Nuclear and high pressure Hydrogen service the Hattersley Parallel slide designs come into their own for pressure classes up to #4500. Size ranges vary according to pressure class required but generally 1/2 to 24″.

Parallel Slide Valve – Blowdown Valves

In smaller sizes 11’2″ and 2″ parallel slide valves make excellent boiler blowdown valves. With the box key handle it complied to the boiler code requirements for blowdown operation. These are PN 25 and PN 40 bronze and steel bodies. For Higher pressure ratings like ANSI class 600 the style changes slightly. For pressure classes 900 to 2500 for disc set up is changed to handle the high pressures and body materials of duplex are not uncommon.

Sluice Valves

Sluice Valves are gate valves used in the waterworks industry, traditionally they were bronze metal seated cast iron valves which were epoxy or bituminous painted. The MSG (metal seated gate) are still available as they give excellent service particularly over extended timeframes and or in buried service applications.

The RSG (resilient seated gate) the modern version has a rubber coated wedge that seats against the valve body flow-path unlike the metal wedge valve that sits in its recessed seat. The RSG valves are now a globally mass produced item and inherently cheaper than our traditional locally made metal seated sluice valves. Again with all our resources across our whole valve range we prefer to sell AUSTRALIAN made product giving our clients the options.

MSG and RSG each have their applications however we would recommend installing the RSG valves in areas or service that allows access for repair or replacement. Sluice valves can be PN 16, PN21, PN25 or PN35 rated and predominantly flanged, socket or spigot ended. To confuse matters dependent usually on the state they are installed they can be clockwise or anti-clockwise closing. AS2638 is the usual compliance requirement for sluice valves. Unlike standard gate valves they do not have handwheels, just a cap so you will have to also specify your operation.