Water jet cutting belongs to the typical working condition of ultra-high pressure water jet. The operation of the equipment is accompanied by extremely high water pressure, frequent pressure impact, and pressure pulsation caused by start stop. The connection position of the pipeline is a high-risk point for faults. The pressure transmitter of ordinary flat joint is prone to water leakage and micro leakage under long-term ultra-high pressure impact, and the pressure cannot be maintained, directly causing problems such as decreased cutting accuracy and equipment shutdown for maintenance. Many waterjet equipment manufacturers prioritize the use of conical ultra-high pressure transmitters. Taking the PTL702Z conical ultra-high pressure transmitter from Shanghai Longlv Electronics as an example, this article analyzes the practical application points from the perspectives of sealing principle, working condition adaptation, installation and operation.

1、 Why is cone ultra-high pressure transmitter preferred for waterjet cutting equipment

Metal cone hard seal, suitable for ultra-high pressure pulsation working conditions

The conical structure relies on the precise bonding of inner and outer conical metal surfaces to form a hard seal, which does not rely on rubber sealing rings for pressure bearing. It is different from the flat joint that relies on O-ring gaskets for sealing. Frequent start stop and pressure relief of waterjet equipment can generate sustained pressure shock, and the rubber seal of the flat mouth is prone to compression aging, deformation and failure due to long-term exposure to ultra-high pressure, resulting in micro leakage; The conical metal seal can resist the alternating load caused by pressure pulses. The higher the high pressure, the better the compression effect of the conical surface, forming a self pressure tight sealing effect and reducing the probability of interface leakage.

Anti vibration and anti impact, suitable for complex working conditions in the workshop

The operation of the water jet high-pressure pump will cause continuous mechanical vibration. Ordinary flat mouth connections are affected by vibration, and the threads are prone to slight looseness, causing the sealing gap to increase and gradually leak water. The conical structure thread is only responsible for providing pre tightening force, and the sealing function is independently undertaken by the conical contact surface. The thread and sealing surface functions are separated, and it is not easy to cause sealing failure under vibration environment, ensuring long-term stability of pressure monitoring, avoiding system pressure drop due to leakage, and ensuring dimensional consistency of waterjet cutting.

Reduce sealing damage caused by impurities in the medium

The water jet medium will carry trace abrasives and small impurities. The flat gasket sealing structure makes it easy for impurities to get stuck between the flat sealing end faces, causing the sealing surface to not be tightly pressed and resulting in water leakage. During the tightening and compression process, the conical surface can push out a small amount of impurities to the outside, reducing the situation of particles being trapped in the sealing contact surface and reducing the risk of leakage caused by impurities. It is more suitable for ultra-high pressure water medium environments with trace abrasive particles.

Ensure the authenticity and reliability of pressure measurement

Once there is a slight leak in the transmitter interface, the system pressure will continue to decrease, and the pressure values collected by the sensor will be low and fluctuate, directly interfering with the equipment control system and causing processing defects such as uneven cutting depth and multiple burrs on the cutting surface. Cone sealing reduces leakage hazards, allowing the water pressure data collected by the transmitter to truly feedback the actual working conditions of the pipeline, providing reliable pressure basis for the water jet numerical control system.

2、 How to avoid leakage of ultra-high pressure water jet equipment and conical ultra-high pressure transmitter

Even if the PTL702Z cone sealing structure ultra-high pressure transmitter is selected, if the selection is not matched properly and the installation operation is not standardized, leakage will still occur. Leakage is not only a problem with the product itself, but also crucial for assembly and maintenance of working conditions. By doing the following points well, the risk of leakage can be greatly reduced.

1. Ensure interface pairing and prohibit mixing different sealing forms of connectors

The conical transmitter must be equipped with a conical high-pressure valve seat interface of the same angle and specification. It is strictly prohibited to forcefully screw the conical transmitter into the threaded hole of the flat pipe. Many on-site faults stem from mixed joints, where the conical and flat surfaces cannot fully fit together, only the threads are subjected to force, and the conical sealing does not work at all. When pressurized, water leakage may occur, and in severe cases, the sensor threads and conical surfaces may be damaged. When renovating equipment, priority should be given to replacing pipeline interfaces with ultra-high pressure valve seats that are compatible with conical surfaces.

2. Perform a thorough inspection and cleaning of the sealing surface

Before installation, carefully inspect the conical surface of the transmitter and the inner conical surface of the equipment valve seat to ensure that there are no scratches, bumps, dents, or burrs; Minor scratches on the sealing surface can form a medium leakage channel. At the same time, cleaning the metal debris, scale, abrasive dust inside the interface can cause particles to be trapped between two sets of conical surfaces, which can damage the metal bonding and form micro leakage points, which are easily overlooked on site. During the transportation and installation process, protect the cone surface and do not collide with hard objects.

3. Strictly control the tightening torque and do not forcefully tighten

Cone sealing relies on appropriate pre tightening force to achieve a tight metal fit, not the tighter the tightening, the better. Too low torque, insufficient contact between the conical surfaces, and leakage under high pressure; Excessive torque can damage the sealing contact surface of the conical surface, causing permanent damage. Even if a new transmitter is replaced in the future, it will continue to leak water. Use a torque wrench to operate according to the specifications for ultra-high voltage joints, and do not forcefully tighten with an adjustable wrench. Ensure that the threads are smooth and aligned during installation, and do not forcefully twist the threads with force to prevent thread deviation and unilateral force on the conical surface.

4. Avoid sealing looseness caused by stress and vibration

The vibration of the water jet high-pressure pump will continue to be transmitted to the transmitter position, so try not to subject the transmitter to mechanical stress in the pipeline. The pipeline cannot forcefully pull the sensor to the hole to avoid residual stress during assembly. Operating vibration will transmit stress to the conical sealing position, gradually leading to gap leakage. If conditions permit, a high-pressure buffer transition joint can be added to reduce the direct transmission of pump body vibration to the transmitter body and minimize the repeated impact of alternating stress on the sealing surface.

5. Maintenance of medium water quality to reduce erosion of sealing surfaces

The fine abrasives and hard impurities in the water of the waterjet will gradually wear down the metal sealing surface when the conical surface is washed away at high speed for a long time. Perform front-end water filtration to reduce solid particles in the medium, minimize abrasive erosion on the cone surface, and extend the service life of the seal.

6. Pressure and leak detection before operation, regular inspection and maintenance

After the installation of the transmitter is completed, slowly increase the pressure to low pressure first, and then gradually increase it to the working pressure of the equipment. Conduct a pressure holding test, observe whether there is water seepage or water droplet marks at the conical surface connection, confirm that there is no leakage, and then officially put it into cutting production. Pay attention to the interface position during daily inspections. Every time the equipment is disassembled, inspected, and maintained, check for wear and damage to the conical surface. If scratches appear, promptly deal with the valve seat or transmitter.

3、 Additional precautions

Cone sealing is not absolutely risk-free, it solves the problem of interface connection leakage. If the medium continues to contain a large amount of hard abrasives and exceeds the allowable pressure overload of the equipment for a long time, it will still cause sealing surface loss. In the waterjet system, the conical ultra-high pressure transmitter solves the shortcoming of flat mouth sealing in ultra-high pressure pulsation scenarios, but in order to achieve long-term stability, selection matching, standardized installation, and regular maintenance are all indispensable.