A needle valve, a manifold, a pressure gauge valve or a siphon tube may seem like minor components within a plant. However, when it comes to isolating an instrument, carrying out a purge, replacing a pressure gauge or protecting it from high temperatures, their role becomes crucial.
At ZAES, we have been working with this type of application for decades and we know that, when it comes to instrumentation, it is not enough simply to choose a product based on its connection or its nominal pressure.
We need to understand what is actually happening at the site.
Which fluid is circulating?.
At what temperature does it operate?.
What pressure must it withstand?.
What type of instrument do you wish to protect?.
And, above all, what is expected to happen when the time comes to carry out maintenance.
That is why our range of needle valves, manifolds, pressure gauge valves and siphon tubes It is designed to be integrated into industrial instrumentation systems where reliability and safety are non-negotiable.
A needle valve is not simply a small valve
The needle valves They are commonly used to isolate or control the flow of liquids and gases to instruments such as pressure gauges, pressure transmitters or pressure switches.
Its design allows for a gradual and controlled opening, which is particularly useful when you do not want the pressure to reach the instrument all at once.
In a chemical plant, an oil and gas facility, a steam line or a process skid, this small detail can make a big difference.
It also allows the instrument to be isolated when it needs to be tested, replaced or serviced.
ZAES offers a range of needle valve configurations for instrumentation and high-pressure applications, including models capable of operating at pressures of up to 413 bar —6,000 psi— and special editions that can reach 690 bar —10,000 psi—, depending on the design and implementation chosen.
But pressure isn’t the only factor that matters.
The material must also be selected taking into account the fluid, the temperature and the environmental conditions at the installation site.
For this reason, instrumentation valves can be manufactured from a range of materials, including:
AISI 316
AISI 316L
Carbon steel
Monel
Inconel
Hastelloy
Duplex
Super Duplex
Not all installations require special materials, but when corrosion, temperature or the process make it necessary, having a range of alternatives to choose from can be crucial.
Manifolds: simplifying an installation also means making it safer
One of the great advantages of a instrumentation manifold is that it allows several functions to be combined within a single unit.
Insulate.
Balance.
Purge.
Air out.
Calibrate.
All this whilst reducing the number of separate fittings and connections that would otherwise need to be fitted.
And this is important because every additional connection also represents a potential point of leakage.
That is why manifolds are so commonly found around pressure transmitters and, in particular, in systems for differential pressure.
2-valve manifold
A widely used configuration for applications in shut-off and purge, also known internationally as Block & Bleed.
It allows the instrument to be isolated from the process and the trapped pressure to be released before carrying out any work.
It is a simple but very useful solution for maintenance and calibration.
3-valve manifold
The three-valve manifold is commonly used in conjunction with differential pressure gauges.
It usually incorporates two isolation valves and one balancing valve.
Its function is to ensure that both pressure lines operate correctly and to protect the instrument during certain manoeuvres.
5-valve manifold
Where greater control is required, the five-valve manifold provides additional purge or venting functions.
It is common to find this type of configuration in installations where it is necessary to check, calibrate or carry out maintenance on a transmitter without disrupting the system’s operation.
ZAES offers a range of configurations and mounting options to adapt the manifold to the type of installation.
Being able to replace a pressure gauge without disrupting the whole plant
Imagine a very common situation.
A pressure gauge needs to be replaced.
If it is connected directly to the pipework, the technician may find that there is no easy way to isolate it.
The solution involves first installing a pressure gauge valve.
Its function is to create a barrier between the process and the instrument.
It seems like a very simple thing, but it makes maintenance work much easier.
Where the valve also incorporates a bleed or vent function, the operator can release any trapped pressure before removing the pressure gauge.
This improves both the safety of the procedure and the ease of maintenance.
For this reason, pressure gauge valves are a common feature in many industrial installations where instruments need to be checked or replaced periodically.
Steam and high temperatures: that’s where the siphon tube comes into play
Another very common problem arises when the pressure gauge has to measure the pressure of a hot fluid.
The best-known example is steam.
Connecting a pressure gauge directly to a steam line can expose the instrument to excessive temperatures and significantly reduce its service life.
The siphon tube for a pressure gauge introduces a thermal barrier between the process and the instrument.
In a steam system, the condensate remaining inside the siphon creates a barrier that helps prevent the temperature from reaching the pressure gauge mechanism directly.
It is a very simple component.
But it plays a very important role.
In fact, in steam systems, it is common to find set-ups in which the siphon tube works in conjunction with a pressure gauge valve.
This protects the instrument from temperature fluctuations and, at the same time, makes it easier to isolate it for maintenance.
The important thing isn’t selling a single item: it’s understanding the whole picture
In industrial instrumentation, a problem is rarely solved by looking at just one component.
A pressure gauge that vibrates may need a dampener.
One installed over a steam source may require a siphon.
An instrument that needs to be dismantled periodically will require an isolation valve.
A differential transmitter may require a manifold.
And a high-pressure line may require a needle valve specifically designed to withstand such conditions.
In certain installations, a configuration might be as follows:
Process → siphon tube → pressure gauge valve → pressure gauge
In other words:
Process → needle valve → pressure transmitter
And in differential pressure applications:
Process → manifold → differential pressure transmitter
There is no single solution that works for all installations.
The important thing is to select the components correctly, taking into account the actual operating conditions.
When it comes to instrumentation, the details matter
At ZAES, we regularly work on applications involving factors such as:
- high pressures;
- high temperatures;
- steam;
- industrial gases;
- corrosive fluids;
- vibrations;
- beats;
- pressure surges;
- routine maintenance operations;
- drainage and venting;
- instrument calibration;
- differential pressure.
For this reason, before selecting a valve or fitting, we always recommend considering the following together:
fluid + pressure + temperature + material + type of connection + function to be performed by the component.
A product may be perfectly suitable for one application but not for another that appears to be similar.
A global market for industrial instrumentation
The international market for instrumentation valves and fittings includes well-known manufacturers such as WIKA, Ashcroft, Swagelok and other international experts.
They all work on solutions designed to connect, isolate and protect measuring instruments within industrial plants.
ZAES operates within this same market sector as a manufacturer specialising in industrial valves and instrumentation.
Our proposal is based on something we consider to be particularly important:
understand the application before proposing a solution.
Because in this industry, it isn’t always the product with the most features that comes out on top.
It is often the case that the right product wins.
A range designed for industry, maintenance and engineering
ZAES needle valves, manifolds, pressure gauge valves and siphon tubes can be used in a wide range of industrial sectors:
Oil & Gas
Chemical industry
Petrochemicals
Refineries
Energy generation
Steam plants
Water treatment
Engineering and EPC
Machinery manufacturers
Process skids
Industrial gases
Industrial maintenance
High-pressure systems
Every sector has its own specific characteristics, but they all share a common need:
that the instruments work properly and can be maintained safely.
Over 60 years’ experience in manufacturing valves for industry
ZAES has been involved in the design, manufacture and supply of industrial valves for over six decades.
Over this period, the facilities have evolved.
Control systems are becoming increasingly sophisticated.
Transmitters are more accurate.
Automation has come to the fore.
But there is one thing that hasn’t changed:
The instruments still require reliable components to connect them properly to the process.
A needle valve, a manifold or a siphon tube may take up just a few centimetres within an industrial installation.
However, when it comes to working on the instrument, those few centimetres can make maintenance work much easier.
And that is precisely the philosophy with which ZAES continues to develop its range of solutions for industrial instrumentation.
Do you need to choose a needle valve, a manifold or a pressure gauge fitting?
Every application is different.
Before selecting a model, we recommend analysing the actual operating conditions:
fluid, pressure, temperature, materials, connection and required function.
ZAES’s technical and sales team can help you determine the most suitable configuration for your installation.
Metalúrgica ZAES, S.L.
Manufacturer of industrial valves and instrumentation solutions.
English (UK) 
Español 
Español de Chile 
Español de México 
Español de Argentina 
Español de Colombia 
Español de Costa Rica 
Español de Ecuador 
Español de Perú 
Español de República Dominicana 
Español de Uruguay