All Gate Valves
All about DAVINCI
RESILIENT SEAT
GATE VALVES
What is a gate valve?
A gate valve is the most common valve for water supply systems. It represents a linear-motion isolation valve and has a function to stop or allow the flow. Gate valves got their name from the closure element sliding into the flow stream to provide shutoff and, therefore, acting like a gate. Gate valves are used to isolate specific areas of the water supply network during maintenance, repair works, new installations, as well as to reroute water flow throughout the pipeline.
Design & parts of a gate valve
A gate valve has a simple design and can be applied in many low pressure-drop services, which makes it one of the most common valves in use today. Gate valves are designed as full-port valves. This means that the valve port is of the same size as the inner diameter of the connecting pipe. Full-bore gate valve passes the fluid flow without any obstructions to a flow and do not cause a pressure drop in a pipeline. This also allows to clean the pipe using a cleaning pig.
A resilient seated gate valve with a non-rising spindle consists of the following parts:
wedge
ductile iron valve body
seating area
stem (spindle)
spindle bearing
bonnet
packing.
The body is the largest element of the gate valve. Since the spindle remains in the valve body during rotation, it allows an economical bonnet construction. The valve bonnet itself is joined to the body with bolts, which allows cleaning and maintenance. As the gate valve closes, the wedge travels down until it presses the valve seat, which would mean a complete shutoff.
During the opening the wedge slides towards the upper part of the valve body.
Gate valve working principle
Gate valves are normally operated by a handwheel, a valve T-key (wrench) or an actuator.
The wheel is attached to a valve stem and transfers rotational energy to it. During the gate valve opening, the rotation of the handwheel turns the threads of the gate stem into the gate and vice versa for closing. This energy moves the gate valve wedge downwards or upwards. In underground gate valve installations, an extension spindle is attached, which allows operation without direct access to the valve itself.
Generally, gate valves are installed in the areas of a pipeline where they will longer remain open or closed, as they generally require sometime to switch between these two positions. However, when the valve needs to be operated quite often or even remotely, motorised gate valves are used
(i.e. equipped with an electric actuator).
Types of Gate Valves
Based on construction, gate valves for water supply systems can generally be divided into the following types:
By wedge: parallel gate valves and wedge gate valves
By seat: metal seat or resilient seated gate valves
By stem: with rising or non-rising stem.
1. Parallel or wedge-shaped gate valves
Parallel slide gate valves feature a flat, parallel-faced gate-like closing element, fitting between two parallel seats. The so-called knife gate valve is a type of parallel gate valves.
Wedge gate valves are so called because of a wedge-shaped gate. The wedge has ribs on both sides and is guided by the slots in the gate valve body.
The wedge guides serve the following purposes:
to transfer the axial loads imposed on the wedge by the medium to the valve body
to enable a low-friction movement of the wedge in radial direction
to prevent the wedge from rotation while travelling between open/closed valve positions (serving as an anti-twist lock).
Most gate valves used in water distribution systems are wedge gate valves.
2. Metal seated or resilient seated gate valves
Wedge gate valves can have metal or resilient seats. In metal seated gate valves, a wedge slides towards a groove in the invert of the gate valve body, which would often trap solids contained in the fluid. For this reason, resilient seated gate valves provide a tighter shut-off and are more preferred in water distribution systems.
In resilient seated gate valves, a wedge, mostly made of ductile iron, is encapsulated in resilient material (elastomer) and therefore provides a tight seal. The seating takes place between the rim of the wedge and the valve body. This does not necessitate a groove at the bottom of the valve. Therefore, resilient seated gate valves can seal around small solids, carried by the water flow. All Hawle gate valves are resilient seated where the valve gate is vulcanized with high-quality elastomer and suitable for application in drinking water supply. For example, in the latest Hawle gate valve model E3 both wedge and the nut are fully coated with elastomer, which allows the highest degree of corrosion protection. We offer a wide variety of connection options for every application.
3. Rising stem or non-rising stem gate valves
The difference of rising to non-rising stems is that they may be either fixed (rising stem) or threaded (non-rising stem) to the gate. In rising stem gate valves, the rotating stem rises as the valve is opened. Some clear disadvantages of the rising-stem valves are:
due to a bulky design they require a greater amount of space when opened as the spindle travels upwards;
they are not suitable for underground or buried installations.
Válvula de Compuerta
Get in Touch
Do you have any question request or comment?
We’d love to hear from you! Fill out this really short form, and we will get right back to you.
¿Tiene alguna pregunta, petición o comentario?
Estaremos encantados de atenderle. Rellene este breve formulario y nos pondremos en contacto con usted lo antes posible.
FAQ
-
What is an FAQ section?An FAQ section can be used to quickly answer common questions about your business like "Where do you ship to?", "What are your opening hours?", or "How can I book a service?".
-
Why do FAQs matter?FAQs are a great way to help site visitors find quick answers to common questions about your business and create a better navigation experience.
-
Where can I add my FAQs?FAQs can be added to any page on your site or to your Wix mobile app, giving access to members on the go.